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Item No. 1 of 24

ACCESSION NO: 0084263 SUBFILE: CRIS
PROJ NO: IOW02463 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED MULTISTATE PROJ NO: NC-157
START: 01 OCT 1996 TERM: 30 SEP 2001 FY: 2001

INVESTIGATOR: Cruse, R. M.; Moore, K. J.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

CROP AND RUMINANT SYSTEMS TO CONSERVE MIDWESTERN UNGLACIATED SOILS AND WATER QUALITY

OBJECTIVES: Evaluate alternative forage production systems in intensive cattle management. 2) Evaluate cattle response to alternative forages. 3) Evaluate forage-grain-cattle management systems that conserve soil and water quality.

APPROACH: Kura clover will be evaluated as a living mulch for corn production. Macronutrient and soil pH requirements of cup-plant will be determined. Yield and composition of stockpiled forages and crop residues for wintering beef cows will be determined. Performance of heifers fed cup-plant will be compared with those fed alfalfa silage. Calf production, reproductive efficiency, forage selection and forage intake by beef cows grazing in year-around systems will be determined. Preferential transport of contaminants under ridge-tillage will be determined. Effects of crop rotation on soil and water quality will be evaluated. Economic analysis of alternative management-intensive grazing systems for beef cattle operations will be developed.

PROGRESS: 1996/10 TO 2001/09
The driftless region is unique and will require unique cropping and animal management systems to maintain fragile soil and water resources. Cropping system trials evaluated production potentials, and in some situations, cropping system impacts on surface runoff water quality. Strip intercropping with corn (Zea mays), soybean (Glycine max), and oat (Avena sativa) resulted in significantly higher crop yields, especially in the corn strip border positions and in oat boarder positions. Overall, total production as evaluated with the land equivalent ratio, increased when averaged across all crops. The system proved quite dynamic in production potential, and year-by-year results were dependent on weather conditions. Under favorable water conditions (adequate rainfall) corn border yields exceeded that in other positions. With a shortage of water, water competition between the small grain and corn in the border position resulted in decreased corn grain yield. Oat yield in the border position, however, was increased. Soybean yields adjacent to corn were decreased relative to strip center positions when rainfall was adequate for optimum production and increased relative to the strip center next to the oat strip. Under water stress, soybeans adjacent to the corn border position yielded comparable to the strip center (and sometimes higher), but yields next to the oat strip were decreased. Water competition between corn and oat existed in drier years, however, competition for nitrogen applied to the corn strip never occurred. Using the basal stalk nitrate test for each row of corn in the corn strip revealed significantly lower stalk nitrate concentrations existed in the border rows relative to the strip center rows. Frequently nitrate concentrations were below sufficiency levels in border rows, even though these rows exhibited the highest corn grain yields. Depleted stalk nitrates were attributed to increased nitrate demand resulting from higher yield potential and not to reduced supply. Economics of the system were compared to that for a conventional corn/soybean rotation. On a land area basis the strip intercropping system was superior. However, with this more complex system less land area could be farmed by a single farmer than if he/she managed a conventional cropping system. Sediment movement in this system as measured with rainfall simulation indicates very favorable soil conservation would result, especially when the rows/strips are planted perpendicular to the slope. Soil loss and water runoff of corn production using a kura clover cover crop was also evaluated. Final analysis of this last study is not complete. However, qualitative evaluation strongly indicates the cover crop system greatly reduced sediment movement in crop plots with slopes of approximately 8 percent.

IMPACT: 1996/10 TO 2001/09
Soil and water resources could be affected very favorably by increased adoption of either the strip intercropping system or corn production using kura clover as a perennial cover crop. This region, with steep slopes and small fields are well suited for either system. Strip intercropping would also permit soybeans to be produced in this area with much less soil and water degradation than typically occurs with conventional systems being used.

PUBLICATIONS: 1996/10 TO 2001/09
1. Ghaffarzadeh M, F Garcia Prechac and RM Cruse. 1997. Tillage Effect on Soil Water Content and Corn Yield in a Strip Intercropping System. Agron. J. 89:893-899.
2. Gilley JE, LA Kramer, RM Cruse and A Hull. 1997. Sediment movement within a strip intercropping system. J. Soil and Water Con. 52:443-447.
3. Mohammadreza G, F Garacia Prechac, RM Cruse and MM Harbur. 1998. Fertilizer and soil nitrogen use by corn and border crops in a strip intercropping system. Agron. J. 90:758-762.
4. Ellsbury MM, DN Exner and RM Cruse RM. 1999. Movement of corn rootworm larvae (Coleoptera: Chrysomelidae) between border rows of soybean and corn in a strip intercropping system. J. Econ. Entomol. 92:207-214.
5. Exner DN, DG Davidson, M Ghaffarzadeh and RM Cruse. 1999. Yields and returns from strip intercropping on six Iowa farms. Amer. J. Alternative Agric. 14(2):69-77.
6. Harbur MM, M Ghaffarzadeh and RM Cruse. 2000. Corn (Zea Mays L.) yield response to N fertilizer in conventional and alternative rotations. J. Iowa Acad. Sci. 107:42-45.
7. Wright SR, DD Buhler, KA Kohler and RM Cruse. 2000. Weed seedbanks and seedling emergence in a two and three crop narrow strip intercropping/rotation system. J. Iowa Acad. Sci. 107(1):10-15.
8. Cruse RM, R Mier and CW Mize. 2001. Surface residue effects on erosion of thawing soils. Soil Sci. Soc. Amer. J. 65:178-184.
9. Ghaffarzadeh M, F Garcia Prechac, RM Cruse and MM Harbur. 2001. Tillage effect on soil water content and soybean yields in a strip intercropping system. J. Iowa Acad. Sci. 108:19-23.
10. Exner DN and RM Cruse. 2001. Profitability of crop rotations in Iowa in a stress environment. J. Iowa Acad. Sci. Accepted.
11. Brummer EC and KJ Moore. 2001. A simple method to increase alfalfa yields in the establishment year. p. 21-22. IN Leopold Center Progress Report, Volume 10, Leopold Center for Sustainable Agriculture, Ames, IA.
12. Harmoney KR, KJ Moore, EC Brummer, CL Burras and JR George. 2001. Spatial legume composition and diversity across seeded landscapes. Agron. J. 93:992-1000.
13. Mitchell RB, DD Redfearn, LE Moser, KJ Moore, RJ Grant and BH Kirch. 1998. Tiller demographics and leaf area index of four perennial grasses. Agron. J. 90:47-53.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 2 of 24

ACCESSION NO: 0092242 SUBFILE: CRIS
PROJ NO: IOW02666 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: REVISED MULTISTATE PROJ NO: NC-174
START: 01 OCT 1998 TERM: 30 SEP 2003 FY: 2002

INVESTIGATOR: Fenton, T. E.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

MANAGEMENT OF ERODED SOILS FOR ENHANCEMENT OF PRODUCTIVITY AND ENVIRONMENTAL QUALITY

OBJECTIVES: 1. Determine erosional and landscape impacts on soil processes and properties. 2. Assess management effects on eroded soil productivity and quality of soil, air and water resources.

APPROACH: 1) Rates of topsoil formation will be documented by measuring the organic carbon content, soil color, and topsoil thickness differences between cropping systems, amendments, soil and water management treatments and check plots. Depth and concentration of fly ash, magnetic susceptibility, and Ce137 will be used to identify erosional sediments. 2) The more promising management alternatives for a soil based on previous research and simulation modeling, will be field tested to determine the yield potential, time required for productivity maintenance and/or economic efficiency. Specific soil parameters and threshold values will be suggested for both surface and subsoil layers. Changes in the surface layer properties that appear to affect productivity under a high level of management include: erosion phase, porosity, bulk density, aggregation, organic C, infiltration, texture, and coarse fragments. Minor and major reductions in inherent soil productivity will be considered as a basis for setting threshold values for measurable and observable soil properties or conditions based on current methods of technology and research. Threshold values will be determined by correlating soil properties with yields obtained from research fields as well as from simulation models. The threshold values will serve as an indicator of reduced productivity capacity.

PROGRESS: 2002/01 TO 2002/12
Factor analysis was used to characterize the relationship between soil and terrain properties of a 16 ha field in central Iowa. Based on the factor loadings of the 20 variables included in the analysis, four factors were characterized as the soil texture and organic matter factor, the pH and Fe factor, the shoulder position factor, and the closed depression factor. These factors were then used in a stepwise regression analysis to describe corn and soybean yields in wet and dry years. The analysis showed that closed depressions and pH were more important in the wet years and that soil texture and shoulder landscape positions were more important in the dry years. Additionally, the soil pH factor was relatively more important for soybean yields than for corn yields. A statewide index of organic carbon content to a depth of 1 meter for the major soil map units in the state is being developed. Existing organic carbon data is being used. Bulk density (1/3 bar) values are calculated based on limited existing data and a prediction model utilizing particle size and soil strength. Analyses of soil properties influencing EM-38 readings are continuing. In a study of hillslope-vegetative zones in restored wetlands on the Des Moines Lobe soils on upland prairie-backslopes produced the highest microbial biomass C for each depth interval. Highest microbial biomass C was from 0-15 cm in all vegetative-slope areas. Highest variability in microbial biomass C was on the upland prairie-backslopes. Soils in the sedge wetlands have the lowest percentage microbial biomass C, suggesting presence of more stable organic fractions due to past erosion/deposition in these areas. Vegetative zone accounted for 52% of the total variability in total C, whereas soil depth accounted for 74% of the total variability in biomass C. Microbial biomass C was significantly related with total C for each vegetative-slope element. Particle size distribution was significantly correlated with microbial biomass and total C in the sedge wetland zones. Restoration, using microbial biomass and total C as indicators, is positively influencing the soil quality in these restored hillslopes.

IMPACT: 2002/01 TO 2002/12
Factors affecting yield variability in wet and dry years were shown to be different. Producers need to be aware of soil properties within their fields and the response of these properties to varying weather conditions. Amount of nitrogen fertilizer required for crops, especially corn, is highly sensitive to the weather-soil properties interactions and producers need to be aware of this fact and make necessary adjustments in nitrogen rates both from an economic and environmental point of view. A better understanding of organic carbon status of soil map units and the influence of landscape position and vegetative type on restored wetland was achieved. Data collected in this study contribute to a better understanding of the rate of change in soil properties and vegetation types in restored wetlands. Managers of restored wetlands, both public and private, can make better decisions when they understand the dynamic and interactions of soil, vegetation, and landscapes.

PUBLICATIONS: 2002/01 TO 2002/12
1. Kaspar TC, TS Colvin, DB Jaynes, DL Karlen, DE James, DW Meek, D Pulido, D and H Butler. 2002. Estimating corn yield using six years of yield data and terrain attributes. IN P.C. Robert et al. (ed.) Proc. of the Fifth Intl. Conf. on Precision Agriculture and Other Resource Management, Bloomington, MN. 16-19 July 2000. [CD-ROM].
2. Brevik EC and TE Fenton 2002. The relative influence of soil water content, clay, temperature, and carbonate minerals on soil electrical conductivity readings taken with an EM-38 along a mollisol catena in central Iowa. Soil Survey Horizons 43(1):9-13.
3. Brevik EC, I Kovda and TE Fenton. 2002. Soil changes beneath white pines over 75 years in central Iowa. Soil Sci. Soc. of Amer. Annual Meeting Abstracts. Published on CD-ROM.
4. Brevik EC and TE Fenton. 2002. The influence of water, clay, temperature, and carbonate minerals on soil electrical conductivity readings taken with an EM-38 in central Iowa. Georgia J. Sci. 60(1):43.
5. Kaspar TC, TB Parkin, CA Cambardella, DL Karlen and YS Jung. 2000. Using the weight-loss-on-ignition method to measure spatial variability of soil carbon. Agron. Abstr. p. 317.
6. Kaspar T, T Parkin, C Cambardella, D Karlen and M Tomer. 2001. Spatial and temporal variability of soil carbon. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
7. Kaspar TC, TS Colvin, DB Jaynes and DL Karlen. 2002. Corn response to nitrogen across landscape positions. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
8. Moran LP and TE Fenton. 2002. Microbial C biomass variability in restored prairie-wetland complexes in the Des Moines Lobe, IA. Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
9. Moran LP and TE Fenton. 2002. Soils and hydrology of restored prairie-wetland complexes in central Iowa: Gordon's Marsh. Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
10. Parkin TB and TC Kaspar. 2000. Response of soil respiration to rainfall and temperature. Agron. Abstr., p. 246-247.
11. Parkin TB and TC Kaspar. 2001. Temporal variability of soil respiration. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
12. Parkin TB and TC Kaspar. 2002. Impact of sampling frequency on CO2 flux estimation. In Annual Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 3 of 24

ACCESSION NO: 0157160 SUBFILE: CRIS
PROJ NO: IOW03094 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 NOV 1996 TERM: 31 DEC 2000 FY: 2000

INVESTIGATOR: Killorn, R. J.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

EFFECT OF NITROGEN SOIL FERTILITY MANAGEMENT ON CROP PRODUCTION AND GROUND WATER QUALITY

OBJECTIVES: a) Study the long-term effects of different methods of N fertility management onthe quantity and distribution of nitrate (NO3-N) in the root zone. b) Study the long-term effects of different methods of N fertility management on crop yield. c) Use the results of objectives 1 and 2 to estimate the effects of different methods of N fertility management on the potential for ground water contamination.

APPROACH: a) Long-term replicated field experiments will be established to study the effect of N rate, time and method of applications, fertilizer material, and nitrification inhibitors on the quantity and distribution of nitrate and ammonium in the rootzone of corn. b) Determine yield and uptake of N by corn grain and stover using the experiments described in a. c) Use the data obtained in a and b to calculate N budgets and estimate the N available for movement to groundwater.

PROGRESS: 1996/11 TO 2000/12
A ten-year N study terminated in 2000. N fertilizer was applied at rates of 0 to 180 kg/ha in 45 kg/ha increments where corn followed soybean and from 0 to 225 kg/ha in 56 kg/ha increments in continuous corn. Treatments were a factorial arrangement of N rates and two rates of nitrapyrin (0 and 0.56 kg/ha ai.). Corn grain yields increased with N rate in both crop rotations every year but one. Corn in the corn-soybean rotation did not respond to application of nitrapyrin but continuous corn grain yields increased an average of 1255 kg/ha in 1996 and decreased an average of 1004 in 1999. Simple economic analyses show that at this site use of nitrapyrin decreased simple profit $79/ha in continuous corn and by the annual cost of the nytraprin in corn after soybean. A study of the effects of Zn application on corn grain yields was conducted at 11 sites over three years. Treatments were paired with and without Zn. Zn was applied at planting 5 cm below and 5 cm to the side of the seed a rate of 5.6 kg/ha to field-length strips. Soils were sampled extensively and analyzed for % organic matter, pH, P, K, and Zn. Yields were measured in paired treatments where soil characteristics were similar. The most common result was no response to Zn addition. However, there were several sites/soil combinations where addition of Zn resulted in yield decreases ranging from 270 kg/ha to 2009 kg/ha. The negative responses occurred where soil test Zn was greater than 0.8 ppm (DTPA exraction) or on soils with low soil test Zn and pH's greater than 7.0. These results suggest that, at this time, there is little value in applying Zn in this way to corn in Iowa and in fact there will be sites within fields where the result of Zn application will decrease yields.

IMPACT: 1996/11 TO 2000/12
These studies suggest that application of nitrapyrin does not result in corn grain yield increases in many years in Iowa. Producers can increase profits by realizing that application of nitrapyrin to corn after soybean is not profitable. Application of nitrapyrin to continuous corn will not produce profitable yield increases in the long term. Application of Zn when soil tests are high does not result in yield increases and may result in yield decreases. This information will increase producer profitability by reducing input costs.

PUBLICATIONS: 1996/11 TO 2000/12
1. Valverde FJ. 1997. Nitrapyrin: Effect on nitrate leaching and corn yields at two Iowa locations. M.S. Thesis. Iowa State Univ., Ames. 75 pp.
2. Hernancez JD. 1999. Zinc and phosphorus nutrition of corn and soybean when by-products are applied: A greedhouse study. M.S. Thesis. Iowa State Univ., Ames. 64 pp.
3. Bickel AD. 2000. Corn response to zinc in Iowa. M.S. Thesis. Iowa State Univ., Ames. 54 pp.
4. Buah SSJ, Polito TA and Killorn R. 1999. No-tillage corn hybrid response to starter fertilizer. J. Prod. Agric. 12:676-680.
5. Buah SSJ, Polito TA and Killorn R. 2000. No-tillage soybean response to banded and broadcast and direct and residual fertilizer phosphorus and potassium applications. Agron. J. 92:657-662.
6. Buah S, Polito TA and Killorn R. 2000. No-tillage corn response to placement of fertilizer nitrogen, phosphorus, and potassium. Commun. Soil Sci. Plant Anal 31:3121-3133.
7. Killorn R. 1999. Effect of frequency of swine manure application on the yield of corn and soybean. pp. 161-163. IN 1998 Swine Res. Rpt. AS-640, Iowa State Univ.
8. Diericks AM and Killorn R. 1999. The effect of zinc sulfate in different corn hybrids grown in samd culture. Agron. Abst. p. 261.
9. Quesada JP, Killorn R and Dierickx AM. 2000. Response of corn grown in two crop rotations to different N rates and nitrapyrin. Agron. Abst. p. 274.
10. Dierickx AM and Killorn R. 2000. Spatial analysis of corn response to zinc in Iowa. Agron. Abst. p. 275.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 4 of 24

ACCESSION NO: 0163429 SUBFILE: CRIS
PROJ NO: IOW03233 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 DEC 1993 TERM: 30 NOV 1999 FY: 2000

INVESTIGATOR: Mallarino, A. P.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

MAINTAINING OPTIMAL PHOSPHORUS AND POTASSIUM FERTILITY IN SOILS UNDER CONSERVATION TILLAGE

OBJECTIVES: The overall objectives of the proposed research is to identify cost-effective methods to maintain P and K fertility in soils under conservation tillage. Specific objectives are to study the effect of different residue management systems on P and K cycling in soils, to identify effective tools to assess P and K fertility, to identify cost effective methods of fertilizer application for maintaining available P and K levels in soils.

APPROACH: At least four long-term trials will be established at locations having distinct soil types, and corn and soybeans will be grown in rotation. Treatments will be various combinations of two tillage systems (no-till and chisel-disk), three fertilizer placements (broadcast, side-banded, and deep-banded), and three rates of P or K fertilizers. At least 10 complementary on-farm trials having similar fertilizer treatments will be established on farmers' cornfields having long histories of ridge-till or no-till systems. Soil samples will be collected periodically from various depths, and will be analyzed for available P and K by various methods. Grain and young plants will be collected and analyzed for P and K content. Soil moisture and temperature for selected treatments will be determined at early growth stages of the crops.

PROGRESS: 1993/12 TO 1999/11
The rapid increase in farmers' adoption of new technologies such as precision agriculture tools and no-till management has generated numerous questions about currently recommended fertilization practices. The objectives of this project were to develop environmentally sound and cost-effective P and K management practices for Iowa corn and soybean grain crops, with especial attention to fields managed with conservation tillage. Twenty long-term trials and about 100 one-year field trials were established since 1994 for corn and soybeans managed with chisel-disk, ridge-till, or no-tillage. The trials included several P and K rates applied broadcast, deep-banded, and banded with the planter. Some on-farm trials used precision agriculture technologies such as yield monitors and variable rate fertilization, manuring, or liming. These trials were established on research farms and on growers' fields. Parallel studies on growers' fields assessed spatial variability of P and K in soils and plants using precision agriculture technologies such as global positioning systems, geographical information systems, and various soil sampling procedures. Data collected were grain yields, plant weights at early growth stages (V5 to V6), and nutrient content of soil and young plants. The results showed significant yield advantage for K deep-banding in many trials for all the tillage systems evaluated, even in some high-testing soils. The P placements seldom influenced grain yield compared with broadcast fertilization, although the banded P increased early growth and reduced the accumulation of P near the soil surface. Responses to starter fertilization always increased corn early growth but increased grain yield only when soil P tests were below soil tests deemed optimum to maximize economic yields. Responses to K placement were poorly related with soil tests or stratification and seemed related with limited moisture in topsoils during early summer. Variable-rate fertilization, liming, or manuring (the latter based on soil-test P levels) did not affect yields but usually reduced the amount of material applied and avoided nutrient applications in parts of the fields that already tested high. A major issue not yet fully solved or understood is the identification of cost-effective intensive soil sampling strategies for best use of the variable rate technology. The results suggest that deep application of K fertilizer could improve fertilizer use efficiency and the economics of fertilizer usage. Variable rate P fertilization and banded (deep or shallow) P placements had little impact in grain yield, usually increased the cost of fertilization, but reduced P loading to soils already testing high and reduced P concentrations near the soil surface of all soils. The new technologies can without doubt improve the efficiency of fertilization and reduce the harmful impact of fertilization on water supplies. However, use of these technologies not always results in greater economic benefits for producers in the short term. Further research is needed to maximize the economic benefit of fertilization and manuring practices that reduce nutrient contamination of water supplies.

IMPACT: 1993/12 TO 1999/11
The project identified P and K application methods that improve fertilizer use efficiency, increase adoption of conservation tillage, and reduce nutrient contamination of water supplies. It also showed that although new precision agriculture technologies can definitely improve fertilizer management, producers have to be very selective and use them carefully to increase farm profitability.

PUBLICATIONS: 1993/12 TO 1999/11
1. Borges, R. and Mallarino, A.P. 2000. Grain yield, early growth, and nutrient uptake of no-till soybean as affected by the phosphorus and potassium placement. Agron. J. 92 (In press).
2. Haq, M.U. and Mallarino, A.P. 2000. Evaluation of soybean yield and nutrient composition as affected y early season foliar fertilization. Agron. J. 92 (In press).
3. Mallarino, A.P. 1999. Alternatives for P and K management: A role for deep banding and starter. pp. 247-253. In: The Integrated Crop Management Conf. Proc. Dec. 1-2, 1999. Iowa State Univ. Extension. Ames.
4. Mallarino, A.P. 1999. Effective use of precision agriculture for improved management of phosphorus, potassium, and lime. pp. 12-13. In: Integrated crop management. IC-482 (Special Precision Ad. Edition). Iowa State Univ. Extension.
5. Mallarino, A.P. 1999. Extracting phosphorus in calcareous soils with the Mehlich III. pp. 7. In: The soil plant analyst. Soil and Plant Analysis Council.
6. Mallarino, A.P. 1999. Phosphorus and potassium management for cost-effective soybean production. pp. 251-258. In: World Soybean Research Conf. VI. Proc. Aug. 4-7, 1999. Chicago, IL.
7. Mallarino, A.P. 1999. Soil phosphorus testing for crop production and environmental purposes. pp. 185-192. In: The Integrated Crop Management Conf. Proc. Dec. 1-2, 1999. Iowa State Univ. Extension. Ames.
8. Atia, A. and Mallarino, A.P. 1999. Soil testing for phosphorus in manured soils. In: Manure Management '99. Proc. June 22-25, 1999. Saskatoon, SK, Canada.
9. Mallarino, A.P. and Sawyer, J. 1999. Interpreting Mehlich-3 Soil Test Results. pp. 11-13. In: The Integrated Crop Management Newsletter. Iowa State Univ. Extension IC-482(2).
10. Mallarino, A.P. and Wittry, D. 1999. Challenges for making intensive soil sampling and VRT pay. Ongoing Iowa studies with phosphorus. pp. 104-109. In: North Central Extension-Industry Soil Fertility Conference. Proceedings. Vol. 15. St. Louis, MO.
11. Mallarino, A.P., Bordoli, J.M. and Borges, R. 1999. Phosphorus and potassium placement effects on early growth and nutrient uptake of no-till corn and relationships with grain yield. Agron. J. 91:37-45.
12. Mallarino, A.P., Oyarzabal, E.S. and Hinz, P.N. 1999. Interpreting within-field relationships between crop yields and soil and plant variables using factor analysis. Precision Agric. 1:15-26.
13. Mallarino, A.P. 1998. The Olsen, Bray-1, and Mehlich-3 P tests: Correlations and field calibration for corn in Iowa soils. Special Workshop. Oct. 18, 1998. ASA Annual Meetings. Baltimore, MD.
14. Borges, R. and Mallarino, A.P. 1998. Significance of spatially variable soil phosphorus and potassium for early growth and nutrient content of no-till corn and soybean. Communic. Soil Sci. Plant Anal. 29:2589-2605.
15. Haq, M.U. and Mallarino, A.P. 1998. Foliar fertilization of soybean at early vegetative stages. Agron. J. 90:763-769.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 5 of 24

ACCESSION NO: 0165477 SUBFILE: CRIS
PROJ NO: IOW03278 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 AUG 1994 TERM: 31 JUL 1999 FY: 1999

INVESTIGATOR: Anderson, C. E.

PERFORMING INSTITUTION:
AGRI & BIOSYSTEMS ENGINEERING
IOWA STATE UNIVERSITY
AMES, IOWA 50011

EVALUATION OF AGRICULTURAL CHEMICAL MANAGEMENT OPTIONS USING SIMULATION MODELS

OBJECTIVES: 1) To evaluate existing chemical simulation models with emphasis on FMBWQ, PRZM-2, and GLEAMS using Iowa field water quality data from the MSEA experimental sites. 2) To develop improved simulation components for chemical adsorption and degradation, preferential flow, and transport of chemicals in subsurface drainage water. 3) To use these models to simulate best management practices for water quality protection.

APPROACH: The Field Moisture Balance Water Quality Model (FMBWQ) has a modular structure and includes functions for tillage, subsurface drainage crop cover and chemical application methods. The primary focus will be on FMBWQ. Components from PRZM-2 and GLEAMS will be incorporated into FMBWQ and tested against the performance of PRZM-2 and GLEAMS using data from the Iowa MSEA and other data from Iowa research sites. New components for chemical fate processes will be developed and tested against the field data. Test runs will be made using soil and chemical parameters over a range representative of Iowa conditions. Different chemical use and management scenarios including tillage, and the timing, rates and methods of chemical application will be simulated. An evaluation will be made of the significance of the results to decision makers.

PROGRESS: 1994/08 TO 1999/07
The impact of crop production on water quality is a major concern in American society. Field testing of chemicals to measure water quality impacts is both time-consuming and expensive, and is itself a source of environmental pollution. Computer models based on field and laboratory research data can be used to predict impacts without polluting the environment, and can also save time and money. Model testing and validation must be done for many combinations of chemical, soil, climate and management systems. The Field Moisture Balance Water Quality (FMBWQ) model was developed by scientists at Iowa State University to study the fate of agricultural chemicals in the environment. The model was developed to simulate the movement of chemicals in fields with artificial subsurface drainage. The model shows improved ability to simulate chemical flows from drained fields.

IMPACT: 1994/08 TO 1999/07
The improved ability to predict the fate of chemicals in artificially drained fields will allow development of management systems which will reduce the adverse impacts of agricultural chemicals on water quality in the Midwestern US.

PUBLICATIONS: 1994/08 TO 1999/07
No publications reported this period

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 6 of 24

ACCESSION NO: 0166266 SUBFILE: CRIS
PROJ NO: IOW03287 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: REVISED MULTISTATE PROJ NO: W-188
START: 01 OCT 1999 TERM: 30 SEP 2004 FY: 2002

INVESTIGATOR: Horton, R.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

CHARACTERIZATION OF FLOW AND TRANSPORT PROCESSES IN SOILS AT DIFFERENT SCALES

OBJECTIVES: 1. To study relationships between flow and transport properties or processes and the spatial and temperal scales at which these are observed. 2. To develop and evaluate instrumentation and methods of analysis for characterization of flow and transport at different scales.

APPROACH: 1. Field distributions of hydraulic properties and solute transport properties will be measured. The measured flow and transport properties will be used to predict chemical leaching to tile drains. 2. Develop heap pulse probe methods to determine soil water content and soil water velocity. Develop a thermo-TDR probe for simultaneous determination of soil water content and bulk density.

NON-TECHNICAL SUMMARY: Because soil properties vary with time and location it is difficult to measure soil water movement and chemical leaching in agricultural fields. A rapid and accurate method for measuring water and chemical leaching will be developed.

PROGRESS: 2002/01 TO 2002/12
Heat pulse sensors have been proposed as promising tools for measuring water fluxes in soil. We have developed a simple theoretical relationship between water flux and the natural log of the ratio of the temperature increase downstream from a line heat source to the temperature increase upstream from a line heat source. To test this simple relationship we performed heat pulse measurements in packed columns of sand, sandy loam, and silt loam subjected to a wide range of water flow rates. Our heat pulse probes consist of three 4 cm stainless steel needles embedded in a waterproof epoxy body. The needles contain resistance heaters and thermocouples. The probes are connected to an external datalogger and power supply. To measure the water flux, a 15 s heat pulse is generated at the middle needle using the power supply and the resistance heater, and the temperature increases at the needles 6 mm upstream and downstream from the heater are recorded using the thermocouples and datalogger. Water fluxes estimated by the heat pulse method are compared with the measured water flux out of the bottom of the columns. In initial tests the heat pulse method provided accurate measurements of water fluxes from 0.5 to 25 cm per hour in sand. For this same range of fluxes, the heat pulse method tended to underestimate the water flux in the sandy loam and silt loam, particularly at the higher flow rates. Laboratory experiments and data analysis are ongoing.

IMPACT: 2002/01 TO 2002/12
New data have been obtained indicating that heat pulses can be used to measure water flow in sand. Because water flow affects leaching of chemicals, this new technique will lead to better measurements and management of chemical leaching through soil.

PUBLICATIONS: 2002/01 TO 2002/12
1. Bachmann J, R Horton, SA Grant and RR van der Ploeg. 2002. Temperature dependence of water retention curves for wettable and water repellent soils. Soil Sci. Soc. Am. J. 66:44-52.
2. Ella VB, SW Melvin, RS Kanwar, LC Jones and R Horton. 2002. Inverse three-dimensional groundwater modeling using the finite-difference method for recharge estimation in a glacial till aquitard. Trans. ASAE 45(3):703B715.
3. Ewing RP and R Horton. 2002. Diffusion in sparsely connected porespaces: Temporal and spatial scaling. Water Resour. Res. 38:10.1029/2002WR001412.
4. Hermsmeyer D, R Diekmann, RR van der Ploeg and R Horton. 2002. Physical properties of a soil substitute derived from an aluminum recycling by-product. J. Hazard. Mater. 95:107-124.
5. Hermsmeyer D, J Ilsemann, J Bachmann, RR van der Ploeg and R Horton. 2002. Model calculations of water dynamics in lysimeters filled with granular wastes. J. Plant Nutr. Soil Sci. 165:339-346.
6. Hermsmeyer D, RR van der Ploeg, R Horton and J Bachmann. 2002. Lysimeter study of water and salt dynamics in a saline metallurgical waste. J. Plant Nutr. Soil Sci. 165:211-219.
7. Ilsemann J, RR van der Ploeg, R Horton and J Bachmann. 2002. Laboratory method for determining immobile water content and mass exchange coefficient. J. Plant Nutr. Soil Sci. 165:332-338.
8. Lee J, LS Hundal, R Horton and ML Thompson. 2002. Sorption and transport behavior of Naphthalene in an aggregated soil. J. Environ. Qual. 31:1716-1721.
9. Shangguan Z, M Shao, R Horton, T Lei, L Qin and J Ma. 2002. A model for regional optimal allocation of irrigation water resources under deficit irrigation and its applications. Agric. Water Manage. 52:139-154.
10. Wang Q, R Horton and J Lee. 2002. A simple model relating soil water characteristic curve and soil solute breakthrough curve. Soil Sci. 167:436-443.
11. Wang Q, R Horton and M Shao. 2002. Effective raindrop kinetic energy influence on soil potassium transport into runoff. Soil Sci. 167:369-376.
12. Wang Q, R Horton and M Shao. 2002. Horizontal infiltration method for determining Brooks-Corey model parameters. Soil Sci. Soc. Am. J. 66:1733-1740.
13. Wang Q, TE Ochsner and R Horton. 2002. Mathematical analysis of heat pulse signals for soil water flux determination. Water Resour. Res. 38:10.1029/2001WR1089.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 7 of 24

ACCESSION NO: 0169181 SUBFILE: CRIS
PROJ NO: IOW03338 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: REVISED MULTISTATE PROJ NO: NC-218
START: 01 OCT 2001 TERM: 30 SEP 2006 FY: 2002

INVESTIGATOR: Tabatabai, M. A.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

ASSESSING NITROGEN MINERALIZATION AND OTHER DIAGNOSTIC CRITERIA TO REFINE NITROGEN RATES FOR CROPS AND MINIMIZE LOSSES

OBJECTIVES: 1. Develop and evaluate rapid tests for N mineralization capacity across the various soils and climatic regimes of the region and determine the feasibility and most appropriate conditions for use of these tests. 2. Conduct fundamental work to enhance current understanding of the role of active C and N pools in cropping systems and to predict net N mineralization as influenced by C sequestration management.

APPROACH: Soil samples from the participating states in the region will be provided to my laboratory for assay of arylamidase activity in soils and for characterization of organic N pools by determination of potential N mineralization and microbial biomass Nitrogen and Carbon. Nitrogen and Carbon mineralization in soils under different tillage and residue management systems will be assessed.

NON-TECHNICAL SUMMARY: Nitrate enrichment of ground water and surface waters and their impact on drinking water quality and hypoxia in the Gulf of Mexico are important water quality issues. Nitrogen use in cropping systems in the North Central Region is one of the major sources of nitrate entering natural waters. This work is focused on better understanding the role of the active carbon and nitrogen pools in nitrogen mineralization and carbon sequestration in soils under different cropping systems. This should allow more accurate recommendations of nitrogen for crop production.

PROGRESS: 2002/01 TO 2002/12
The enzyme B-glucosaminidase (EC 3.2.1.30) is involved in C and N cycling in soils. The effects of crop rotations and N fertilization on B-glucosaminidase activity and its relationship to N mineralization were studied in soils of two long-term field experiments involving different cropping systems at the Northeast Research Center (NERC) and Clarion-Webster Research Center (CWRC) in Iowa that were initiated in 1978 and 1954, respectively. Surface soil samples (0-15 cm) were taken in 1996 and 1997 in corn (Zea mays L.), soybean (Glycine max (L) Merr.), oats (Avena sativa L.), or meadow (alfalfa) (Medicago sativa L.) plots that received 0 or 180 kg N/ha before corn and an annual application of 20 kg P and 56 kg K/ha. The B-glucosaminidase activity in the soils was assayed at optimal pH (acetate buffer, pH 5.5); microbial biomass C (Cmic) and N (Nmic) were determined by chloroform-fumigation methods; N mineralization was studied in leaching columns under aerobic conditions at 30C for 24 weeks. The activities of B-glucosaminidase were significantly affected by crop rotation (p < 0.001) and N fertilization (p ranging from 0.05 to 0.001). Generally, the highest enzyme activity was obtained in soils under 4-year corn-oats-meadow rotations taken under meadow, and the lowest continuous mono-cropping systems. The activity of this enzyme was significantly correlated with Corg (r ranging from 0.42** to 0.76***), Norg (ranged from not significant at one site one year to r = 0.76***), Cmic (r ranging from 0.44** to 0.71***), and Nmic (r ranging from 0.33* to 0.76***) in soils, and with cumulative N mineralized (r > 0.84*** and r > 0.79*** at the NERC and CWRC sites, respectively). The results suggest that B-glucosaminidase plays a major role in N mineralization in soils and is affected by cropping systems; i.e., ecosystem function and health.

IMPACT: 2002/01 TO 2002/12
Cropping systems impact a key enzyme involved in N mineralization. B-Glucsoaminidase activity can be used to predict N mineralization in soils.

PUBLICATIONS: 2002/01 TO 2002/12
1. Acosta-Martinez V and MA Tabatabai. 2002. Inhibition of arylamidase activity in soils by toluene. Soil Biol. Biochem 34:229-237.
2. Ekenler M and MA Tabatabai. 2002. Effects of trace elements on B-glucosaminidase activity in soils. Soil Biol. Biochem. 34:1829-1832.
3. Lacorbiniere-Jn-Baptiste M. 2002. Nutrient-enriched mixtures of exogenous humic substances as organic fertilizers. M.S. Thesis. Iowa State Univ., Ames. 108 p.
4. Dodor DE. 2002. Enzyme activities in soils as affected by long-term cropping systems. Ph.D Dissertation. Iowa State Univ., Ames. 268 p.
5. Dodor DE and MA Tabatabai. 2002. Effects of cropping systems and microbial biomass on arylamidase activity in soils. Biol. Fetil. Soils 35:253-261.
6. Ekenler M. 2002. Enzyme activities in soils as affected by management practices. Ph.D Dissertation, Iowa State Univ., Ames. 280 p.
7. Ekenler M and MA Tabatabai. 2002. B-Glucosaminidase activity of soils: effect of cropping systems and its relationship to nitrogen mineralization. Biol Fertil Soils 36:307-376.
8. Ekenler M and MA Tabatabai. 2002. Liming and tillage effects of the activities of fifteen enzymes in soils. Agron. Abstr. (on CD)
9. Ekenler M and MA Tabatabai. 2002. B-Glucosaminidase activity and nitrogen mineralization in soils under different cropping systems. Agron. Abstr. (on CD)
10. Tabatabai MA, AM Garcia-Manzanedo and V Acosta-Martinez. 2002. Substrate specificity of arylamidase in soils. Soil Biol. Biochem. 34:103-110.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 8 of 24

ACCESSION NO: 0169987 SUBFILE: CRIS
PROJ NO: IOW03351 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 NOV 1995 TERM: 31 OCT 2000 FY: 2000

INVESTIGATOR: Blackmer, A. M.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

OPTIMIZING NITROGEN MANAGEMENT FOR CORN

OBJECTIVES: Develop methodology by which new and emerging technologies can be used to formulate and continuously refine N-fertilizer recommendations for corn that meaningfully address variations due to seasons, fields, positions within fields, times of application, and methods of application.

APPROACH: Studies will be conducted on fields of many cooperating corn producers. Nitrogenfertilizer treatments will be applied to replicated plots or strips at various rates and times by using various methods. Soil samples will be collected for analysis in late spring. Some analyses will involve laboratory incubation studies of N mineralization, immobilization, and turnover in samples collected at sites where field observations are being made. Spatial patterns in N status will be characterized by aerial photography. Nitrogen status at the end of the season will be evaluated by sampling and testing cornstalks at selected sites. Yields of grain will be measured by hand-picking of small plots and(or) by combines equipped with yield monitors and positioning systems. Geographic information systems will be used to establish spatial relationships among observations made within fields. All information will be analyzed in aggregate within appropriate categories to determine how optimal rates of fertilization vary with known soil characteristics and management history as well as weather conditions before fertilizers were applied.

PROGRESS: 1995/11 TO 2000/10
Studies were conducted to develop methodology by which new and emerging technologies can be used to formulate and refine N fertilizer recommendations that address variability due to weather, fields, positions within fields, time of application, and method of application. Strip-plot trials were conducted on farmer's fields at more than 50 sites that covered a total of more than 500 ha. Each site had received fall-applied N as manure or anhydrous ammonia. Each trial included applying extra fertilizer N at various rates in replicated and randomized strips in Spring, remote sensing to characterize spatial patterns in soil color and canopy reflectance, tissue testing to characterize end-of-season stalk nitrate concentrations, and measuring yields with on-the-go-yield monitors on combines. Differential global positioning systems were used to record points of data collection, and geographic information systems were used to establish relationships among the various levels of data collected. The results provide compelling evidence that substantial amounts of the fall-applied N were lost before corn crops were 30 cm tall. The results also showed that in-season fertilization was an effective way to reduce N losses to the environment and increase profits for farmers. Results show that in-season fertilization after silking is an effective way to rescue yields after large losses of fertilizer N occur. Together with similar observations made on previous years, the results show a need to avoid N management guidelines that ignore the important effects of weather, methods of N application, and time of application. The late-spring test for soil nitrate was shown to be an effective tool for adjusting N fertilization practices for weather. On-farm trials with precision farming technologies were shown to be an effective and efficient way to evaluate and improve N management practices.

IMPACT: 1995/11 TO 2000/10
Farmers, fertilizer dealers, and the popular press have shown great interest in learning more about the results of these studies. The information gathered, however, has had little effect on government programs focusing on required nutrient management plans that ignore time of application and weather as factors affecting N losses from soils, N fertilizer needs, and profits for producers.

PUBLICATIONS: 1995/11 TO 2000/10
Balkcom KS. 2000. Early season losses of fertilizer nitrogen during corn production. Ph.D. Dissertation. Iowa State Univ., Ames. 81 pp.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 9 of 24

ACCESSION NO: 0170503 SUBFILE: CRIS
PROJ NO: IOW03356 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 02 JAN 1996 TERM: 30 NOV 2001 FY: 2002

INVESTIGATOR: Batchelor, W. D.

PERFORMING INSTITUTION:
AGRI & BIOSYSTEMS ENGINEERING
IOWA STATE UNIVERSITY
AMES, IOWA 50011

EVALUATION OF MODELS TO PREDICT CROP GROWTH IN AGRICULTURAL SYSTEMS

OBJECTIVES: The goal of this project is to adapt soybean and corn crop growth models to Iowaagronomic and climatic conditions. The objectives are to (1) collect baseline data to validate biomass components of process-oriented crop growth models for different agronomic, environmental, and management conditions in Iowa, and (2) develop new model components to improve predictions of plant growth.

APPROACH: Objective 1 will be achieved by collecting soybean and corn growth data from three research farms representing different soil types and environmental conditions in Iowa. Different varieties and hybrids will be planted for 5 years and crop growth and development will be measured periodically throughout the season. The data will be used to test the crop model predictions of growth and development. Limitations in model predictions will be evaluated. Objective 2 will be achieved by developing new model components to improve predicted crop growth in cases where the model performed poorly in objective 1. This will include development of new components based on theoretical analysis of crop growth and incorporating existing process level models into the soybean and corn models.

PROGRESS: 1996/01 TO 2001/11
This project has satisfied the primary objective of developing datasets to test and improve corn and soybean models in Iowa. Baseline datasets for corn and soybeans were collected during the period 1995-2001. Many improvements to both CROPGRO and CERES-Maize were made to improve predictions of growth and development processes. These models have been used as a tool to analyze research data and assess the impact of management decisions on crop production.

IMPACT: 1996/01 TO 2001/11
Techniques developed in this project have help determine causes of spatial yield variability, and the break-even costs associated with moving from single rate to variable rate management.

PUBLICATIONS: 1996/01 TO 2001/11
1. Bootlink HWG, JJ Stoorvogel, BJ Van Alphen, R Vargas, WD Batchelor and JO Paz. 2001. Tools for optimizing management of spatially-variable fields. Ag Systems 70(2-3):445-476.
2. Lizaso JI, WD Batchelor and N Boedhram. 2001. Alternate approach to improve kernel number calculation in CERES-Maize. Trans. of the ASAE 4(4):1011-1018.
3. Irmak A, JW Jones, WD Batchelor and JO Paz. 2001. Estimating spatially variable soil properties for application of crop models in precision agriculture. Trans. of the ASAE 44(5):1343-1353.
4. Seidl MS, WD Batchelor, JB Fallick and JO Paz. 2001. GIS-crop model based decision support system to evaluate corn and soybean prescriptions. Applied Engineering in Agriculture 17(5):80-87.
5. Paz JO, WD Batchelor, GL Tylka and RG Hartzler. 2001. A modeling approach to quantify the effects of spatial soybean yield limiting factors. Trans. of the ASAE 44(5):1329-1334.
6. Paz JO, WD Batchelor and GL Tylka. 2001. Method to use crop growth models to estimate potential return for variable-rate management in soybeans. Trans. of the ASAE 44(5):1335-1341
7. Boedhram N, TJ Arkebauer and WD Batchelor. 2001. Season-long Characterization of Vertical Distribution of Leaf Area in Corn. Agronomy Journal 93(6):1235-1242.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 10 of 24

ACCESSION NO: 0177030 SUBFILE: CRIS
PROJ NO: IOW03516 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 15 NOV 1997 TERM: 14 NOV 2002 FY: 2002

INVESTIGATOR: Carriquiry, A. L.

PERFORMING INSTITUTION:
STATISTICS
IOWA STATE UNIVERSITY
AMES, IOWA 50011

A BAYESIAN DECISION MODEL FOR NUTRIENT APPLICATION RATES

OBJECTIVES: Develop a decision model to guide fertilizer application rates with and without information from a soil test. Formulate the decision problem in a fully Bayesian framework, to properly account for all uncertainties. Generalize the usual production function model by expressing it as a changepoint regression with an independent variable that is subject to measurement error. Investigate modeling approaches that would allow incorporation of a physical decay model for nitrates in the soil.

APPROACH: Build upon the simple decision model presented by Babcock, Carriquiry, and Stern (Applied Statistics, 1996) to include measurement error in the production function, as well as measurement error and a model for the decay of nitrates in the soil in the expressions for expected profit. Estimation of all marginal posterior distributions of interest will be carried out using Markov chain Monte Carlo methods. The Gibbs sampler will be used whenever possible; else, a Metropolis algorithm will be applied. In order to address sources of variation in expected profit, such as year-to-year and location-to-location variability, the decision model will be built using a hierarchical structure.

PROGRESS: 1997/11 TO 2002/11
During the final phase of this project, we extended our original model, and formulated it in multi-layer hierarchical form, that permits incorporating covariate information at several levels of the model. For example, in the first level, crop output depends on inputs such as nutrients and the efficiency with which those are used. In the second level, the efficiency in the use of inputs may depend on factors such as distance of the firm from the closest metropolitan area, education of firm manager, and other non-production factors. In parallel, we worked on the problem of drawing inference about a single input but controlling for other input used in production. To this end, we derived expressions for estimating technical efficiency associated to only one input at the firm level, and proposed methods to estimate the corresponding parameters.

IMPACT: 1997/11 TO 2002/11
The family of models considered, and the estimation approach developed in this project have wide application. Similar approaches can be used to assess efficiency in the use of any input to any production process at the firm level. The possibility of focusing on a single input while accounting for the rest in the model permits investigating whether one input is more strongly associated to efficiency of production (or lack thereof) than the remaining inputs.

PUBLICATIONS: 1997/11 TO 2002/11
1. Leonidas A, AL Carriquiry, J Zhao and XB Yang. 2003. Impact of management practices on regional prevalence of soybean Sclerotinia stem rot in the north-central region of the United States and on farmers' decisions under uncertainty. Plant Disease. In press.
2. Carriquiry AL. 2003. Estimation of usual intake distributions of nutrients and foods. Journal of Nutrition. In press.
3. Fernandez S, R Fernando and AL Carriquiry. 2001. An algorithm to sample marker genotypes in a pedigree with loops. Case Studies in Bayesian Statistics, Vol. V, Gatsonis, C. et al. (eds.). Lecture Notes in Statistics, Springer-Verlag. 309-328.
4. Carriquiry AL and M Daniels. 2001. Adjusting for measurement error of a dietary risk factor in age-related maculopathy. ISBA 2000 Proceedings: Bayesian Methods with Applications to Science, Policy, and Official Statistics. Italy: European Communities Press. 51-61.
5. Fernandez SA, RL Fernando and AL Carriquiry. 2001. An algorithm to sample unobservable genotypes in complex pedigrees. ISBA 2000 Proceedings: Bayesian Methods with Applications to Science, Policy, and Official Statistics. Italy: European Communities Press. 125-135.
6. Daniels MJ and AL Carriquiry. 2002. Computing the posterior distribution of individual level usual intakes with application to diseases models. Research in Official Statistics 1:67-81.
7. Carriquiry AL and SM Nusser. 2003. An alternative approach to analyze food consumption data. (Invited discussion.) Journal of the American Statistical Association. In press.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 11 of 24

ACCESSION NO: 0180789 SUBFILE: CRIS
PROJ NO: IOW03563 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 DEC 1998 TERM: 31 DEC 2000

INVESTIGATOR: Loynachan, T. E.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

BRADYRHIZOBIAL AND MYCORRHIZAE INVOLVEMENT WITH SUSTAINED FIELD PRODUCTIVITY OF SOYBEAN

OBJECTIVES: (1) To determine the range of N2-fixation efficiency of Bradyrhizobium in Iowa soils associated with soybean, distribution of strains, and evaluate methods of quickly assessing strain identification and distribution in specific soils; and (2) to determine the range of P-supplying ability of endomycorrhizal fungi in Iowa soils associated with soybean, distribution of strains, and evaluate methods of quickly assessing strain identification and distribution in specific soils.

APPROACH: The working hypothesis of this research is that edaphic factors active in individual soil sites have resulted in development over time of site-specific bradyrhizobia and mycorrhizal fungi. Soils sampled will be (i) characteristic of Iowa soils, (ii) well characterized for chemical, physical, and selected biolkogical properties, and (iii) show a wide range of edaphic conditions thought important in providing selection pressure for bradyrhizobia and mycorrhizal fungi. Field samples will be collected when soybean is at the R1-R3 growth stage. The dominant bradyrhizobia from each site will be characterized by phage typing and further characterized for efficiency in N2 fixation in the greenhouse. Additionally, the mycorrhizal fungi will be characterized by FAME analyses (procedures ro be worked out) and their efficiency for increased P availability to plants evaluated in the greenhouse. After greenhouse testing, dominant bacterial and fungal species will be correlated with specific soil traits and with the presence of the other co-symbiont, and their overall efficiencies in N2-fixing and P-providing proficiency will be correlated with soil traits. Further greenhouse testing will evaluate interactions of efficient strains in combination.

PROGRESS: 1998/12 TO 2000/12
This project evaluated the synergistic relationships among soybean, beneficial mycorrhizal fungi, and beneficial bradyrhizobial bacteria. The working hypothesis of the research was that edaphic factors developed at specific locations over time have altered the types of organisms present in the soil. The first portion of the study showed that mycorrhizal spores survive in the field in higher numbers under corn than under soybean, and that more poorly drained soils have higher spore numbers than better-drained soils. This may be a fungal response to lower soil aeration, resulting in the fungi converting from a vegetative mode to a survival or reproductive mode. In earlier work, soil pH was adjusted to three levels (pH 5.5, 7.0, and 8.2) with three soil moisture potentials (-7.5, -33.3, and -100 kPa) in factorial combination. Mycorrhizal fungi responded differently under these stress conditions. Root colonization by G. etunicatum was the highest at soil pH 5.5 and decreased with increasing pH. In contrast, percentage root colonization of G. mosseae was the highest at pH 8.2 and decreased significantly with decreasing soil pH. Of the two species, G. etunicatum showed higher colonization and greater plant growth at each pH-moisture combination. Work this year evaluated in the greenhouse nitrogen-fixation efficiency of field isolates compared with a standard rhizobial inoculant and a nitrogen control where N was provided in inorganic form. The field isolates were separated based on FAME analyses. Differences in field isolates in their ability to fix nitrogen were observed. Some strains were as good as the commercial inoculant, whereas others were less effective than the commercial inoculant. Overall, this study showed that considerable variation exists in field isolates and that soil conditions may well be determinant factors in N and P nutrition in Iowa fields for soybean growth provided by bradyrhizobial bacteria and mycorrhizal fungi.

IMPACT: 1998/12 TO 2000/12
Beneficial biological systems have evolved with time, before human manipulation, to provide two of the three major macronutrients to growing plants. Enhanced P availability is provided by beneficial fungi and enhanced N is provided to legumes by nitrogen-fixing bacteria. This study indicates that there is considerable specificity of fungal-plant and bacterial-plant interactions. For reduced input in systems of long-term agricultural sustainability, a better understanding of these biological partners is critically needed. Recognizing that differences exist is the first step in attempts to manipulate the soil environmental system to maximum biological benefits. Manipulation may be through altering soil conditions or breeding for soybean plants that favor specific microorganisms.

PUBLICATIONS: 1998/12 TO 2000/12
Loynachan TE. 2000. Mycorrhizae and their role towards natural resource management. p. 70. Conference Proceedings: International Conference on Managing Natural Resources for Sustainable Agricultural Production in the 21st Century, New Delhi (invited).

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 12 of 24

ACCESSION NO: 0184123 SUBFILE: CRIS
PROJ NO: IOW03801 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 SEP 1999 TERM: 31 AUG 2004 FY: 2002

INVESTIGATOR: Delate, K. M.; Domoto, P. A.; Nonnecke, G. R.; Christians, N. E.

PERFORMING INSTITUTION:
HORTICULTURE
IOWA STATE UNIVERSITY
AMES, IOWA 50011

IMPROVING THE SUSTAINABILITY OF IOWA'S HORTICULTURAL AND AGRONOMIC CROPS

OBJECTIVES: (1) Enhance Iowa's environmental quality through the development of sustainable/organic horticultural and agronomic crop systems (2) Increase the percentage of value-added products through improved sustainable/organic production and postharvest techniques (3) Improve the sustainable/organic agricultural knowledge base of key agricultural professionals by providing research-based information in public training sessions (4) Promote alternative agricultural markets by analyzing alternative marketing strategies for the Iowa producer.

APPROACH: Research on sustainable/organic production practices for horticultural and agronomic crops lags far behind what producers require for full participation in the marketplace. Before new sustainable production or postharvest practices can be recommended, these methods must be thoroughly evaluated under Iowa environmental conditions. The general procedures for the Sustainable/Organic Agriculture research program include the following: (1) Establish plots/greenhouses dedicated to sustainable/organic research; (2) Implement production and management regimes, examining crop rotations, soil media, soil amendments, pest management, and postharvest practices; (3) Evaluate the biological and economic outcomes of the different systems; and (4) Conduct research on alternative markets for value-added products. Several projects have been initiated to develop recommendations, including the "Long-Term Effects of Organic and Conventional Grain/Forage Production" project to examine the agroecological and economic performance of conventional and organic systems, using required practices for certified organic production. Also in their second year are the following projects: "Tillage Effects on Organic Grain Production," "Alternative Soil Amendments/Media for Organic Horticultural Crops," "Organic Fruit Production and Value-Added Products," "Value-Added Research and Demonstration Sites." Experiments have been initiated to evaluate four tillage methods in combination with two planting methods for organic soybean production following Conservation Reserve Program (CRP) land. Two on-farm trials will complement the experiment station trial. Included in the fruit studies are experiments conducted to monitor differences in plant performance and yield in treated vs. untreated sections of the orchard, using mulches, traps, and other methods approved for certified organic apple production. Postharvest comparisons for nutritional quality and microbial load will be conducted on organic vs. conventional apple cider. To evaluate sustainable production systems for June-bearing and day-neutral strawberries, replicated field experiments will be established to compare 1) conventional systems, 2) best-management practices, 3) organically grown with processed manure; and 4) organically grown with corn gluten meal. In order to increase interest and supply of organic value-added products in Iowa, we have established two sites to provide a demonstration of organic soybean and herb growing methods, economics, and yields. Investigations into alternative markets streams, including co-operatives, have been explored. We will also utilize new and promising technologies by preparing and serving various value-added soy and herb products at Field Days held at the demonstration sites.

NON-TECHNICAL SUMMARY: Iowans remain concerned about profitability, the environment, and the quality of life associated with agriculture. This project addresses the need for research-based information for sustainable/organic systems. Indicators of success will include numbers of producers adopting practices to improve or protect soil/water quality; percentage reduction of harmful contaminants in Iowa waters; and numbers of producers and acres in certified organic production.

PROGRESS: 2002/01 TO 2002/12
In fifteen grain, vegetable, fruit, and turfgrass research projects across Iowa, research results have identified that crops fertilized with approved soil amendments yield similar results as conventional fertilizers and promote soil health parameters, including organic carbon pools and microbial biomass. Organic rotations at the Neely-Kinyon Long-Term Agroecological Research site, which included corn-soybean-oats-alfalfa, produced equivalent yields to conventional corn/soybean rotations, and organic yields exceeded conventional when corn and soybean crops followed two years of alfalfa. Soil quality (in terms of organic matter carbon) remained high in the organic system after plowing and secondary tillage events. Economic analysis determined a greater return with organic crops that utilize less off-farm inputs, even when organic premium prices were excluded. Sustainable fruit and vegetable production systems for Iowa that utilize corn gluten meal for weed control and scab-resistant apple cultivars have been developed. High-quality, organic day-neutral strawberries were produced using compost and corn gluten meal. In conditions of low disease pressure, effects from applications of biological disease control treatments (Bacillus subtilis and Trichoderma harzianum) were not significant. Interest in commercial grape plantings, including organic grapes, continues to increase in Iowa. Experiments were established in 2002 to identify which grape cultivars and management system (using various weed management options) will provide the most optimum yield and quality. With vineyard establishment costs in excess of $4,000 per acre, the identification of adapted grape cultivars will allow growers to avoid significant losses associated with planting non-adapted cultivars. Effective pest management practices will be necessary for continued viability of organic agriculture. Kaolin clay products were effective in controlling grape leafhoppers in organic grapes. Pest insects were controlled in organic squash, destined for the organic baby food market, through the use of floating row covers. Alternative woolen mat, flax straw mat, and oat straw mulch treatments for organic herb production (St. John's Wort and catnip) controlled weed populations below hand-weeded plots. Catnip yields were enhanced with mulch treatments and bioactive constituents (nepetalactone and hypericin) remained high. Results demonstrated that the use of soil amendments, such as zeolite clinoptilolite with fertilizer, may enhance turf quality. Efforts have resulted in a significant increase in agronomic and horticultural operations farmed or maintained without potentially polluting levels of nitrates and synthetic pesticides. Longer crop rotations, which included small grains and legumes, provide yield stability, improved plant protection, enhanced soil health and economic benefits, compared to conventional systems with shorter corn/soybean rotations and greater off-farm inputs. Premium prices for certified organic crops, averaging 200% above conventional prices, have increased the economic base of Iowa's farm families.

IMPACT: 2002/01 TO 2002/12
Efforts have resulted in a significant increase in agronomic and horticultural operations farmed or maintained without potentially polluting levels of nitrates and synthetic pesticides. Longer crop rotations, which included small grains and legumes, provided greater yields while maintaining soil health. This rotation also resulted in economic returns three times the returns from to conventional systems with shorter corn/soybean rotations and greater off-farm inputs. Insect pest populations were maintained below economic threshold levels without the use of synthetic controls, relying instead on existing natural enemies (parasitic wasps and predacious insects) to further lower costs of production by 10%.

PUBLICATIONS: 2002/01 TO 2002/12
1. Delate K. 2002. Using an agroecological approach to farming systems research. HortTechnology 12(3):345-354.
2. Delate K, C Cambardella and D Karlen. 2002. Transition Strategies for Post-CRP Certified Organic Grain Production. Published 28 August 2002. Crop Management www.plantmanagementnetwork.org/pub/cm/research/postcrp/
3. Delate K and V Lawson. 2002. Effect of Soil Amendments and Cover Crops on Growth and Productivity of Peppers under Organic Management. Biol. Ag. and Horticulture 21(1).
4. Friedrich H, K Delate, P Domoto and G Nonnecke. 2002. Effect of Organic Pest Management Techniques on Apple Productivity and Quality. Biol. Ag. and Horticulture 21(1).
5. Delate KM and C Cambardella. 2002. Organic Farming Initiative/Long-Term Agroecological Research in Iowa-Fourth Year Report. Leopold Center for Sustainable Agriculture Annual Report, Iowa State University, Ames, IA.
6. Delate K, C Cambardella and J Secor. 2002. Feasibility of Organic Soybean Production following CRP land. Iowa State University. McNay Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
7. Delate K and L Rossiter. 2002. Organic Corn Variety Trials. Iowa State University Allee Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
8. Delate K and C Rossiter. 2002. Organic Demonstration Garden Results. Iowa State University Allee Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
9. Delate KM and C Cambardella. 2002. Comparison of fourth year organic and conventional rotations at the Neely-Kinyon Long-Term Agroecological Research (LTAR) site. Iowa State University Armstrong Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
10. Delate K and K VanDee. 2002. Comparison of Organic Corn, Soybean and Barley Varieties, Iowa State University Crawfordsville Research and Demonstration Farm Progress Report, Iowa State University, Ames, IA.
11. Delate KM and C Cambardella. 2002. Evaluation of Edamame Soybean Varieties-Neely-Kinyon Farm, Iowa State University Armstrong Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
12. Delate KM and C Cambardella. 2002. Evaluation of Tofu Soybean Varieties-Neely-Kinyon Farm, Iowa State University Armstrong Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
13. Delate KM and C Cambardella. 2002. Organic Sweet Corn Pest Management Trials-Neely-Kinyon Farm, Iowa State University Armstrong Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
14. Delate KM and C Cambardella. 2002. Open-Pollinated Corn Variety Trial-Neely-Kinyon Farm, Iowa State University Armstrong Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
15. Delate KM and C Cambardella. 2002. Compost Rate Study-Neely-Kinyon Farm, Iowa State University Armstrong Research and Demonstration Farm Progress Report, College of Agriculture, Iowa State University, Ames, IA.
16. Dilley CA, GR Nonnecke and NE Christians. 2002. Corn-based Extracts to Manage Weeds and Provide Nitrogen in Matted-row Strawberry Culture. HortSci. 37(7):1053-1056.
17. Reicher ZJ, GA Hardebeck, FF Yelverton, NE Christians, B Bingaman and J Turner. 2002. Tolerance to Quinclorac by Seedling Creeping Bentgrass HortSci. 37(1):210-213.
18. Nonnecke GR and NE Christians. 2002. Effects of source, rate and particle size of corn gluten meal on weed and strawberry growth and development. Proc. Of the 5th N. Amer. Strawberry Conf. p. 124-128.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu
URL: http://www.ag.iastate.edu/iaexp/projects/cp/IOW03801.html

Item No. 13 of 24

ACCESSION NO: 0185428 SUBFILE: CRIS
PROJ NO: IOW03903 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 JUL 2001 TERM: 30 JUN 2006 FY: 2002

INVESTIGATOR: Thompson, M. L.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

SUSTAINABLE AND ENVIRONMENTALLY SAFE MANAGEMENT OF SOIL RESOURCES

OBJECTIVES: 1. To improve nutrient management guidelines to increase input effectiveness and decrease environmental risks. 2. To determine the impact of microbial symbionts on soybean growth and the impacts of soil management on microbial biomass, enzyme activity, and biological diversity in soils. 3. To develop a more complete data base of soil resources that will improve predictions of the spatial variability of soil properties and processes and to document the short-term and long-term impacts of soil management on soil quality. 4. To identify and quantify the fundamental processes that determine the fate and transport of metals and pesticides once they are applied to the soil or where they occur in contaminated soils.

APPROACH: Work for this project is described and being performed under the following projects IOW04003, IOW04103, IOW04203 and IOW04303.

NON-TECHNICAL SUMMARY: Recommendations about soil management depend on knowledge of nutrient uptake, the role of microorganisms in making nutrients available to plants, the impacts of soil erosion, and the mobility of chemicals applied to the soil. We hope to improve recommendations for crop nutrient applications, learn how soil management impacts microbial activity, improve predictions of spatial variability of soil and improve models that predict transport of chemicals in soil.

PROGRESS: 2002/01 TO 2002/12
This is an administrative project. All progress is reported under projects IOW04003, IOW04103, IOW04203, and IOW04303.

PUBLICATIONS: 2002/01 TO 2002/12
No publications reported this period

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 14 of 24

ACCESSION NO: 0188836 SUBFILE: CRIS
PROJ NO: IOW04003 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 JUL 2001 TERM: 30 JUN 2006 FY: 2002

INVESTIGATOR: Killorn, R. J.; Al-Kaisi, M.; Blackmer, A. M.; Henning, S. J.; Mallarino, A. M.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

SUSTAINABLE AND ENVIRONMENTALLY SAFE MANAGEMENT OF SOIL RESOURCES: NUTRIENT MANAGEMENT

OBJECTIVES: To improve nutrient management guidelines to increase input effectiveness and decrease environmental risks. Sub-objectives are: 1. Determine the transformations and movements of agronomic crop nutrients in soils. 2. Improve methods to assess the availability of nutrients to agronomic crops. 3. Determine sufficiency levels of nutrients in agronomic plants and develop guidelines to help producers attain those levels in crops. 4. Identify toxicity problems for agronomic crops in soils and develop recommendations to avoid or correct the problems. 5. Identify methods of applying nutrients to maximize benefits and minimize costs.

APPROACH: 1. Collect soil and plant samples periodically during the growing season from fertilizer and biosolids rate studies to find nutrient content and to determine sufficiency levels. 2. Collect soil and soil-water samples from different soil depths from studies to monitor the movement of plant nutrients, especially nitrate and phosphate. 3. Investigate new methods to assess nutrient availability in soils. 4. Explore the use of remote sensing techniques to assess nutrient availability. 5. Use laboratory and field studies to determine toxic concentrations of various elements commonly found in soils. 6. Study different methods of nutrient application including, but not limited to, different soil placements and foliar application. 7. Use the data generated from the studies to formulate or refine soil fertility management recommendations to reflect economically and environmentally sound practices. Additional Investigators: Polito TA, Sawyer JE, Batchelor WD.

NON-TECHNICAL SUMMARY: Poor management of nutrients can result in soil degradation by nutrient depletion or accumulation of unwanted substances in the soil. Excessive applications of plant nutrients can result in contamination of water supplies. Nonrenewable resources are consumed during the manufacture and delivery of fertilizers. This project will provide crop producers with objective, current, and reliable information about the merits of various nutrient management practices.

PROGRESS: 2002/01 TO 2002/12
This year's research suggests that soil pH is an important factor affecting the rate at which fall-applied N is nitrified and, therefore, the susceptibility of this N to loss during spring rainfall. Neither corn yield nor N-uptake was consistently affected by addition of nitrapyrin to spring-applied anhydrous ammonia in either continuous corn or a corn-soybean rotation in a ten-year study. Differences in the amount of NH4 and NO3 remaining in the soil following harvest were not affected by addition of nitrapyrin in the study. Numerous field studies and subsequent laboratory analyses suggest that the Mehlich 3 soil P extractant works well for predicting P fertilizer needs but, if ICP is used to measure the P in the extracts, more P is found than if a colorimetric method is used. This strongly suggests that field calibration of the Mehlich 3-ICP analysis methodology is required. Evaluation of variable-rate fertilizer application showed that while this management method usually does not result in increased crop yields it does reduce the amount of fertilizer material applied on a field basis.

IMPACT: 2002/01 TO 2002/12
Crop producers must pay attention to soil pH when applying N in the fall. Failure to do so will reduce the effectiveness of the N, increasing N lost from fields, which can contaminate Iowa's ground and surface water. Iowa farmers should not add nitrapyrin to spring applied anhydrous ammonia. This finding will reduce farmers' costs of production. Field calibration of the Mehlich 3-ICP soil P analysis method will result in rational P fertilizer recommendations and help insure that crop producers apply P to fields where it is required. Recognition of the strengths and weakness of the use of variable-rate fertilizer application will insure that Iowa crop producers' perception of use of this system is realistic and allow them to make informed decisions about the use of the methodology.

PUBLICATIONS: 2002/01 TO 2002/12
1. Zhang J. 2002. Remote sensing of nitrogen deficiencies in cornfields. Ph.D. Disseration. Iowa State Univ,. Ames.
2. Blackmer AM. 2002. Understanding the end-of-season test for cornstalk nitrate. p. 65-71. Proc. of the 14th annual integrated crop management conference. Iowa State Univ., Ames
3. Blackmer AM. 2002. Early season losses of nitrogen form Iowa cornfields. p. 61-73. Proc. of the 14th annual integrated crop management conference. Iowa State Univ., Ames
4. Rakshit S, JE Sawyer, JP Lundvall, DW Barker and AP Mallarino. 2002. Liquid swine manure nitrogen utilization project. In Agronomy Abstracts, ASA, Madison, WI.
5. Sawyer JE, ER Loria, DW Barker and JC Lorimor. 2002. Use of anaerobic digested swine manure in corn production. In Agronomy Abstracts, ASA, Madison, WI.
6. Loria ER, JE Sawyer and JC Lorimor. 2002. Comparison of phosphorus and nitrogen from raw and anaerobic digested swine manure. In Agronomy Abstracts, ASA, Madison, WI.
7. Barbazan M, A Mallarino and J Sawyer. 2002. Liquid swine manure phosphorus utilization in corn-soybean production. In Agronomy Abstracts, ASA, Madison, WI.
8. Barbazan MM, AP Mallarino, A Atia and JE Sawyer. 2001. Evaluation of phosphorus availability in manured soils by soil testing and plant analysis. In Agronomy Abstracts, ASA, Madison, WI.
9. Loria ER. 2002. Use of anaerobically digested swine manure in corn production. M.S. Thesis. Iowa State Univ., Ames.
10. Atia AM and AP Mallarino. 2002. Agronomic and environmental phosphorus testing for soils receiving swine manure. Soil Sci. Soc. Am. J. 66:1696-1705.
11. Bermudez M and AP Mallarino. 2002. Yield and early growth responses to starter fertilizer in no-till corn. Agron. J. 94:1024-1033.
12. Bianchini AA and AP Mallarino. 2002. Soil sampling alternatives and variable-rate liming for a soybean-corn rotation. Agron. J. 94:1355-1366.
13. Mallarino AP, BM Stewart, JL Baker, JA Downing and JE Sawyer. 2002. Phosphorus indexing for cropland: Overview and basic concepts of the Iowa phosphorus index. J. Soil Water Conserv. 57:440-447.
14. Lorimor J, AP Mallarino, JE Sawyer and J Creswell. 2002. Manure resources. Nutrient Management Information Sheet No. 3. Iowa State Univ. Extension.
15. Mallarino AP, JE Sawyer and J Creswell. 2002. Phosphorus application. Nutrient Management Information Sheet No. 2. Iowa State Univ. Extension.
16. Mallarino AP, JE Sawyer and J Creswell. 2002. Soil testing. Nutrient Management Information Sheet No. 1. Iowa State Univ. Extension.
17. Mallarino AP, JE Sawyer, B Stewart and J Creswell. 2002. Nutrient management plan. Nutrient Management Information Sheet No. 8. Iowa State Univ. Extension.
18. Sawyer JE and AP Mallarino. 2002. Corn leaf potassium deficiency symptoms. In The Integrated Crop Management Newsletter. IC-488(15). Iowa State Univ. Extension.
19. Sawyer JE, AP Mallarino, R Killorn and SK Barnhart. 2002. General guide for crop nutrient recommendations in Iowa. Publ. Pm-1688 (Rev.). Iowa State Univ. Extension.
20. Klatt JG, AP Mallarino and BL Allen. 2002. Relationships between soil phosphorus and phosphorus in surface runoff and subsurface drainage. An overview of ongoing research. p. 183-189. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 17. Des Moines, IA.
21. Mallarino AP, DJ Wittry and PA Barbagelata. 2002. Iowa soil-test field calibration research update: Potassium and the Mehlich-3 ICP phosphorus test. p. 29-39. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 17. Des Moines, IA.
22. Wittry DJ and AP Mallarino. 2002. Use of variable-rate technology for agronomic and environmental phosphorus-based liquid swine manure management. In P.C. Robert et al. (ed.). Sixth Intl. Conf. on Site-Specific Management for Agricultural Systems. Proceedings. CD-ROM. ASA, CSSA, SSSA, Madison, WI.
23. Allen BL, AP Mallarino, JG Klatt, JL Baker and M Camara. 2002. Soil and runoff phosphorus relationships for five typical Iowa soils. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
24. Barbazan MM, AP Mallarino and JE Sawyer. 2002. Liquid swine manure phosphorus utilization in corn-soybean rotations. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
25. Bermudez M, AP Mallarino and DJ Wittry. 2002. Grain yield and soil-test spatial variability under uniform or variable-rate phosphorus and potassium fertilization. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
26. Kaiser DE, AP Mallarino and M Bermudez. 2002. Influence of broadcast and in-the-furrow starter phosphorus and potassium fertilization on corn grain yield, early growth, and nutrient uptake. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
27. Karlen DL, EG Hurley, SS Andrews, MD Duffy, AP Mallarino and CA Cambardella. 2002. Does soil quality show an economic benefit for long-term crop rotations? Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
28. Klatt JG, AP Mallarino, JL Baker, JC Lorimor, RS Kanwar and CH Pedersen. 2002. Phosphorus in soil and tile water as affected by fertilizer and manure applications to artificially drained Iowa fields. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
29. Mallarino AP. 2002. Using variable-rate technology and the phosphorus index for agronomic and environmental phosphorus management at a field level. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
30. Rakshit S, JE Sawyer, JP Lundvall, DW Barker and AP Mallarino. 2002. Liquid swine manure nitrogen utilization project. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
31. Sawchik J, AP Mallarino, M Bermudez and DJ Wittry. 2002. Relating soil tests and within-field yield response to phosphorus and potassium using various sampling strategies. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
32. Wittry DJ, AP Mallarino and P Barbagelata. 2002. Ammonium acetate, Mehlich-3, and sodium tetraphenyl-boron soil potassium tests for corn and soybean. Agron. Abs. CD-ROM. ASA-CSSA-SSSA, Madison, WI.
33. Henriquez C and R Killorn. 2002. Variations in Soil P Forms Under Sugar Cane After Organic and Inorganic P Fertilization. Agron. Abs. ASA-CSSA-SSSA, Madison, WI.
34. Hernandez J and R Killorn. 2002. The Effect of Swine Manure and Biosolid Application on the Interaction of Phosphorus and Molybdenum in Iowa Soils. Agron. Abs. ASA-CSSA-SSSA, Madison, WI.
35. Jensen K and R Killorn. 2002. Effect of Reformulated Nitrapyrin upon Corn Grain Yields in Iowa. Agron. Abs. ASA-CSSA-SSSA, Madison, WI.
36. Quesada JP. 2002. Response of corn yield in two crop rotations to different nitrogen rates and nitrapyrin: A 10-year study. M.S. Thesis. Iowa State Univ., Ames.
37. Henriquez C. 2002. Assessing soil phosphorus status under different agronomic land use. Ph.D. dissertation. Iowa State Univ., Ames.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 15 of 24

ACCESSION NO: 0188837 SUBFILE: CRIS
PROJ NO: IOW04103 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 JUL 2001 TERM: 30 JUN 2006 FY: 2002

INVESTIGATOR: Halverson, L. J.; Loynachan, T. E.; Tabatabai, M. A.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

SUSTAINABLE AND ENVIRONMENTALLY SAFE MANAGEMENT OF SOIL RESOURCES: SOIL BIOLOGY

OBJECTIVES: To determine the impact of microbial symbionts on soybean growth and the impacts of soil management on microbial biomass, enzyme activity, and biological diversity in soils. Sub-objectives are: 1. Assess the impact of Bradyrhizobium japonicum in Iowa soils on soybean growth, the distribution of strains, and rapid methods for strain identification. 2. Assess effects of tillage and residue management practices on temporal and spatial variability of enzyme activities in soils. 3. Assess effects of management practices on the organismal and genetic diversity of microorganisms in Iowa soils. 4. Quantify effects of water deprivation on soil bacteria and identify stress-response mechanisms.

APPROACH: 1. Use long-term field experiments in Iowa to measure the effects of soil management, including tillage, residue placement, fertilizer application, crop rotations, and liming on the activities of 15 enzymes involved in N, S, and P mineralization and organic matter decomposition. 2. Quantify the effects of trace elements and heavy metals on the activities of key enzymes in soils. 3. Use greenhouse studies (where fungal variables can be controlled) to determine the efficacy of AM fungi isolated from Iowa soils. 4. Determine which soil isolates of AM fungi are most effective in providing P to growing plants by assessing their diversity using fatty acid methyl ester techniques. 5. Assess the nitrogen-fixing abilities of microbial field isolates in soybean monoculture on two divergent-background cultivars in the greenhouse.

NON-TECHNICAL SUMMARY: Activities of soil microorganisms are key to the transformation of carbon, nitrogen, phosphorus, and sulfur in soils and to nutrient uptake by plants. This research explores the regulation of soil enzymes, the impact of nitrogen fixing bacteria on soybean growth, the ways in which soil fungi impact plant uptake of phosphorus, and the response of microbial communities in soil to environmental stress.

PROGRESS: 2002/01 TO 2002/12
Substantial progress has been made in the soil biology component of the project, particularly in furthering our understanding of how cropping systems influence nutrient cycling, the availability of nutrients to bacteria in soil and the rhizosphere at microbially-releveant scales, the diversity of arbuscular mycorrhizal fungi associataed with soybean roots, and the properties of bacterial surface growth under unsaturated conditions. In the area of nutrient cycling, we have made signficant advances in our understanding of how the activity of various soil enzymes (B-glucosamindase and B-hexominidase) are influenced by cropping systems and how their activity affects N-mineralization in two Iowa soils that are part of long-term cropping systems studies. The findings indicate that cropping systems and N-fertilization strongly influences these transformations and may influence carbon and nitrogen cycling in Iowa soils and hence long-term crop productivity. We have made dramatic advances in developing genetic tools that allow us to evaluate the bioavailability of nutrients and/or organic pollutants to bacteria in soil or the rhizosphere. These genetic systems allow us to quantify the availability of a compound to a bacterium or to assess whether a nutrient was transiently available (ephemeral) or available at low levels. These tools will facilitate development of better models on the activity of individual microbes and for exploring a habitat or specific stimulus at microbially relevant scales. We are currently developing techniques to optimally recover arbuscular mycorrhizal DNA from plant roots to characterize their diversity in Iowa soils and to mass-produce inocula from single spore cultures. Optimization of these techniques is essential if we are to develop a better understanding of how mycorrhizal diversity and their symbiotic association with plants influences crop productivity as well as rhizobial interactions with leguminous plants. We have explored the ultrastructural properties of unsaturated Pseudomonas putida biofilms to better our understanding of how reduced water availability influences bacterial growth and their metabolic activities. Biofilm development under unsaturated conditions is a dynamic process that appears to require intercellulalar communication to coordinate the activities of the members of the microcolony. There appear to distinct fates for individual cells that influence their survival in the community and this apparent programmed cell death probably requires cel-cell communication to co-ordinate the death of members since they die in a non-random fashion. Further work is needed to determine whether death is caused by exposure to toxic metabolites or some environmental signal indicating the community is best served by the sacrifice of certain members, possibly to improve nutrient acquisition or to serve as site for deposition of toxic metabolites. We are also making continued progress on identifying and characterizing the functional properties of genes that are induced under desiccating conditions.

IMPACT: 2002/01 TO 2002/12
The results of these studies are contributing greatly to our ability to better predict how management practices influence nitrogen mineralization processes and to reduce undesirable losses of nitrogen that could potentially contaminate ground and surface waters. Furthermore, this information will contribute to a better understanding of the interrelationships between nitrogen mineralization processes and carbon sequestration. The new genetic tools that we have developed will aid the research community interested in furthering our understanding of habitat conditions, bioavailability, or bacterial gene expression at microbially-relevant scales, which is important for furthering our understanding of how environmental factors influence nutrient transformations, organic pollutant biodegradation, or adaptive responses to environmental stresses. Our findings on the effects of water deprivation on the ultrastructural properties and behavior of individual cells within unsaturated biofilms and the mechanisms they employ to adapt to water deficits will further our understanding of how to improve the activities of indigenous bacteria or those introduced into the environment for beneficial purposes.

PUBLICATIONS: 2002/01 TO 2002/12
1. Casavant NC, GA Beattie, GJ Phillips and LJ Halverson. 2002. A site-specific recombination-based genetic system for reporting transient or low-level gene expression. Applied and Environmental Microbiology 68:3588-3596.
2. Dodor DE. 2002. Enzyme activities in soils as affected by long-term cropping systems. Ph.D. Dissertation. Iowa State Univ., Ames. 268 p.
3. Dodor DE and MA Tabatabai. 2002. Cropping systems and microbial biomass effects on arylamidase activity in soils. Biol. Fertil. Soils 35:253-261.
4. Ekenler M. 2002. Enzyme activities in soils as affected by management practices. Ph.D. Dissertation. Iowa State Univ., Ames. 280 p.
5. Ekenler M and MA Tabatabai. 2002. Effects of trace elements on b-glucosaminidase activity in soils. Soil Biol. Biochem. 34:1829-1832.
6. Ekenler M and MA Tabatabai. 2002. b-Glucosaminidase activity in soils; effect of cropping systems and its relationship to nitrogen mineralization. Boil. Fertil. Soils 36:367-376.
7. Klose S and MA Tabatabai. 2002. Response of amidohydrolases in soils to chloroform fumigation. J. Plant Nutr. Soil Sci. 165:125-132.
8. Klose S and MA Tabatabai. 2002. Response of phosphomonoesterases in soils to chloroform fumigation. J. Plant Nutr. Soil Sci. 165:1429-1434.
9. Klose S and MA Tabatabai. 2002. Response of glycosidases in soils to chloroform fumigation. Biol. Fertil. Soils 35:262-269.
10. LaCorbiniere-Jn-Baptiste M. 2002. Nutrient-enriched mixtures of exogenic humic substances as organic fertilizers. M.S. Thesis. Iowa State Univ., Ames. 108 p.
11. Merrill LS and LJ Halverson. 2002. Seasonal variation in microbial communities and malodor indicator compound concentrations in various types of swine manure storage systems. J. of Environ. Quality 31:2074-2085.
12. Stiner L and LJ Halverson. 2002. Development and characterization of a green fluorescent protein-based bacterial biosensor for bioavailable toluene and related compounds. Applied and Environmental Microbiology 68:1962-1971.
13. Tabatabai MA and WA Dick. 2002. Soil enzymes: research and development in measuring activities. p 567-596. IN: RG Burns and RP Dick (eds.) Enzymes in the Environment: Activity, Ecology, and Applications. Marcel Dekker, New York.
14. Tabatabai MA. 2002. Soil enzymes. 5:2899-2910. IN: The Encyclopedia of Environmental Microbiology. G. Bitton (ed.), Wiley.
15. Ekenler M and MA Tabatabai. 2002. Liming and tillage effects on the activities of fifteen enzymes in soils. Annual Meetings of the Soil Sci. Soc Am., Indianapolis (on CD).
16. Ekenler M and MA Tabatabai. 2002. b-Glucosaminidase activity and nitrogen mineralization in soils under different cropping systems. Annual Meetings of the Soil Sci. Soc Am., Indianapolis (on CD).
17. Halverson L. 2002. Biofilm development in terrestrial habitats. Am. Phytopathological Soc. Annual Meeting. Milwaukee WI.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 16 of 24

ACCESSION NO: 0188839 SUBFILE: CRIS
PROJ NO: IOW04303 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 JUL 2001 TERM: 30 JUN 2006 FY: 2002

INVESTIGATOR: Thompson, M. L.; Horton, R.; Tabatabai, M. A.

PERFORMING INSTITUTION:
AGRONOMY
IOWA STATE UNIVERSITY
AMES, IOWA 50011

SUSTAINABLE AND ENVIRONMENTALLY SAFE MANAGEMENT OF SOIL RESOURCES: FATE AND TRANSPORT OF CHEMICALS IN SOILS

OBJECTIVES: To identify and quantify the fundamental processes that determine the fate and transport of metals and pesticides once they are applied to the soil or where they occur in contaminated soils. Sub-objectives are: 1. Determine how surfactant molecules affect sorption, mobility, and persistence of pesticides in soil. 2. Determine the mineralogical and microenvironmental contexts of lead, nickel, copper, and zinc in the solid and liquid phases of metals-contaminated soils. 3. Determine the impacts of soil chemical properties (e.g., pH, free Fe and Al oxides, organic C) and physical properties (e.g., particle size distribution) on sorption of oxyanions by soils. 4. Develop laboratory and field techniques that can quantify transport properties of soil.

APPROACH: 1. Quantify the impact of concentration of co-applied surfactants on the biodegradability of atrazine applied to soil. 2. Measure the abundance and chemical forms of trace metals in abandoned mine spoil to estimate the mobility and potential availability of the metals to plants. 3. Identify the minerals that control plant-available forms of zinc and lead in mine spoil. 4. Determine the binding constants for lead and copper with fulvic acids derived from biosolids that are land-applied. 5. Determine the impact of complexation with dissolved organic matter on mobility of trace metals in soil material. 6. Conduct batch sorption experiments with anions such as phosphate and selenate using a suite of soils with a wide range of chemical, physical, and mineralogical properties. 7. Test an in situ sensor to monitor soil water content, water potential, and concentration of organic chemicals in soils with a wide range of chemical and physical properties. 8. Using both batch and soil column techniques, identify the chemical and physical regulators of sorption and transport of hydrophobic organic chemicals in aggregated soils. 9. Test a mathematical model for evaluating pollutant movement in sparsely interconnected pore spaces to understand how diffusion rates into and out of these materials differ from those in more porous materials. 10. Test a mathematical model that comprehensively describes fate and transport of hydrophobic organic chemicals in unsaturated, nonisothermal, salty soil.

NON-TECHNICAL SUMMARY: When pesticides and metals enter the soil they are affected by three major processes: i) immobilization by complexation and/or sorption at soil mineral surfaces, ii) mobility in soil water, or iii) transformation by biological or abiotic reactions. This project focuses on the chemical fate and physical mobility of pesticides, cationic metals, and anionic metals in soils.

PROGRESS: 2002/01 TO 2002/12
Investigations continued into effects of low pore connectivity on diffusive transport. Such limiting connectivity can be seen in fracture networks (e.g., aggregate interiors and cracking clay soils) and rock matrices (e.g., sand grains and gravel aquifer material). We examined how tortuosity and porosity scale with both size and connectivity. Percolation theory predicts a mean cluster radius of gyration that scales with the medium's proximity to the percolation threshold. When the sample size is greater than this radius, then the radius can be used to determine the size of any edge effect in pore accessibility. When the sample is smaller than the radius, the whole sample is effectively edge. This edge effect scaling of accessible porosity was evident in simulated media, and a similar edge effect was seen in calculations of tortuosity. The simulation results suggested a way to estimate tortuosity, and thereby diffusivity, based upon the proximity to the percolation threshold. Using this new approach, predicted and simulated diffusivities compared well. The present work strictly applies only to random media. Future work will evaluate the influence of soil structure. An alkaline hydrolysis method for assessing the potentially hydrolysable organic N pool in soils was developed. It involves determination of the ammonium-N produced by steam distillation of 1 g of field-moist soil with 20 ml of 1M KOH, NaOH, or LiOH or PO4-B3O7 buffer (pH = 11.8). The cumulative amounts of N hydrolyzed followed exponential curves that could be fitted to either hyperbolic or first-order equation. The kinetic parameters of the hyperbolic equation, Nmax (maximum hydrolyzable or mineralizable N) and Kt (time required to hydrolyze one-half of Nmax) were calculated by linear regression of the transformed data, and those of first-order equation, No (potentially mineralizable N), k (hydrolysable rate constant), and t1/2 (time required to hydrolyze one-half of No) by non-linear least square method. The fate and transport of many chemicals in soils depends greatly on the amount and quality of soil organic matter. The spatial distribution of organic matter therefore has an enormous impact on transport in both surface and subsurface soil horizons. Uncertainties in estimates of carbon distribution vary with the technique and the scale of the data used to make the estimate. Because the costs of collecting and analyzing soil samples are substantial, it is imperative to identify the most cost-effective protocols. The choice of optimal spatial scales on which organic matter distributions can be estimated must balance the uncertainty of estimating soil organic carbon contents against the costs of making such estimates.

IMPACT: 2002/01 TO 2002/12
In this project, we are exploring the best ways to predict the fate of chemicals that are applied to soils. To improve our predictions of how fast chemicals can move in soils even when soil water is not moving, we have developed new ways to estimate the complex pathways of soil pores. Some chemicals in soils can be broken down by microorganisms if there is enough nitrogen. To predict better how much soil nitrogen is available to microorganisms, we have improved a laboratory method that is based on how fast ammonium can be produced in a soil sample under controlled conditions. Finally, movement of chemicals in soils depends in part on the quantity and quality of soil organic matter. To predict better the spatial variability of soil organic matter and thus improve predictions of chemical movement, we have begun a project to determine how far apart from one another soil samples should be collected to maximize information gained but still minimize the sampling cost.

PUBLICATIONS: 2002/01 TO 2002/12
1. Acosta-Martinez V and MA Tabatabai. 2001. Inhibition of arylamidase activity in soils by toluene. Soil Biol. Biochem. 34:229-237.
2. Al-Jabri SA, R Horton, DB Jaynes and A Gaur. 2002. Field determination of soil hydraulic and chemical transport properties. Soil Sci. 167:353-368.
3. Al-Jabri SA, R Horton and DB Jaynes. 2002. A point-source method for rapid simultaneous estimation of soil hydraulic and chemical transport properties. Soil Sci. Soc. Am. J. 66:12-18.
4. Bachmann J, R Horton, SA Grant and RR van der Ploeg. 2002. Temperature dependence of water retention curves for wettable and water repellent soils. Soil Sci. Soc. Am. J. 66:44-52.
5. Dodor DE. 2002. Enzyme activities in soils as affected by long-term cropping systems. Ph.D. dissertation. Iowa State Univ., Ames. 268 p.
6. Dodor DE and MA Tabatabai. 2002. Cropping systems and microbial biomass effects on arylamidase activity in soils. Biol. Fertil. Soils 35:253-261.
7. Ekenler M. 2002. Enzyme activities in soils as affected by management practices. Ph.D. dissertation. Iowa State Univ., Ames. 280 p.
8. Ekenler M and MA Tabatabai. 2002. B-Glucosaminidase activity in soils; effect of cropping systems and its relationship to nitrogen mineralization. Boil. Fertil. Soils 36:367-376.
9. Ekenler M and MA Tabatabai. 2002. Effects of trace elements on B-glucosaminidase activity in soils. Soil Biol. Biochem. 34:1829-1832.
10. Ekenler M and MA Tabatabai. 2002. Liming and tillage effects on the activities of fifteen enzymes in soils. Annual Meetings of the Soil Sci. Soc Am., Indianapolis (on CD).
11. Ekenler M and MA Tabatabai. 2002. B-Glucosaminidase activity and nitrogen mineralization in soils under different cropping systems. Annual Meetings of the Soil Sci. Soc Am., Indianapolis (on CD).
12. Ella VB, SW Melvin, RS Kanwar, LC Jones and R Horton. 2002. Inverse three-dimensional groundwater modeling using the finite-difference method for recharge estimation in a glacial till aquitard. Trans. ASAE 45(3):703-715.
13. Ewing RP and R Horton. 2002. Diffusion in sparsely connected porespaces: Temporal and spatial scaling. Water Resour. Res. 38(12) doi 10.1029/2002WR001412.
14. Hermsmeyer D, J Ilsemann, J Bachmann, RR van der Ploeg and R Horton. 2002. Model calculations of water dynamics in lysimeters filled with granular wastes. J. Plant Nutr. Soil Sci. 165:339-346.
15. Hermsmeyer D, R Diekmann, RR van der Ploeg and R Horton. 2002. Physical properties of a soil substitute derived from an aluminum recycling by-product. J. Hazard. Mater. 95:107-124.
16. Hermsmeyer D, RR van der Ploeg, R Horton and J Bachmann. 2002. Lysimeter study of water and salt dynamics in a saline metallurgical waste. J. Plant Nutr. Soil Sci. 165:211-219.
17. Ilsemann J, RR van der Ploeg, R Horton and J Bachmann. 2002. Laboratory method for determining immobile water content and mass exchange coefficient. J. Plant Nutr. Soil Sci. 165:332-338.
18. Klose S and MA Tabatabai. 2002. Response of amidohydrolases in soils to chloroform fumigation. J. Plant Nutr. Soil Sci. 165:125-132.
19. Klose S and MA Tabatabai. 2002. Response of glycosidases in soils to chloroform fumigation. Biol. Fertil. Soils 35:262-269.
20. Klose S and MA Tabatabai. 2002. Response of phosphomonoesterases in soils to chloroform fumigation. J. Plant Nutr. Soil Sci. 165:1429-1434.
21. LaCorbiniere-Jn-Baptiste M. 2002. Nutrient-enriched mixtures of exogenic humic substances as organic fertilizers. MS thesis. Iowa State Univ., Ames. 108 p.
22. Lee J, LS Hundal, R Horton and ML Thompson. 2002. Sorption and transport behavior of Naphthalene in an aggregated soil. J. Environ. Qual. 31:1716-1721.
23. Lee J, R Horton and DB Jaynes. 2002. The feasibility of shallow time domain reflectometry probes to describe solute transport through undisturbed soil cores. Soil Sci. Soc. Am. J. 66:53-57.
24. Mao J-D, LS Hundal, ML Thompson and K Schmidt-Rohr. 2002. Correlation of poly(methylene)-rich aliphatic domains in humic substances with sorption of a nonpolar organic contaminant, phenanthrene. Environ. Sci. Technol. 36:929-936.
25. Shangguan Z, M Shao, R Horton, T Lei, L Qin and J Ma. 2002. A model for regional optimal allocation of irrigation water resources under deficit irrigation and its applications. Agric. Water Manage. 52:139-154.
26. Tabatabai MA. 2002. Soil enzymes. 5:2899-2910. In: The Encyclopedia of Environmental Microbiology. G. Bitton (ed.), Wiley.
27. Tabatabai MA, A Garcia-Manzanedo and V Acosta-Martinez. 2001. Substrate specificity of arylamidase in soils. Soil Biol. Bochem. 34:103-110.
28. Tabatabai MA and WA Dick. 2001. Soil enzymes: research and development in measuring activities. p 567-596. IN: RG Burns and RP Dick (eds.) Enzymes in the Environment: Activity, Ecology, and Applications. Marcel Dekker, New York.
29. Thompson ML and L Ukrainczyk. 2002. Micas. p. 431-466. IN: JB Dixon and Darrell Schulze (ed.) Soil Mineralogy with Environmental Applications. Soil Sci. Soc. Am. Book Ser. 7. Madison, WI.
30. Thompson M, R Conant, W Dick, A Dobermann, M Ransom and J Stuth. 2002. Estimating stocks of soil organic carbon at multiple scales. Soil Sci. Soc. Am. Annual Meeting (Indianapolis, Nov. 2002) Abstracts.
31. Wang Q, R Horton and J Lee. 2002. A simple model relating soil water characteristic curve and soil solute breakthrough curve. Soil Sci. 167:436-443.
32. Wang Q, R Horton and M Shao. 2002. Effective raindrop kinetic energy influence on soil potassium transport into runoff. Soil Sci. 167:369-376.
33. Wang Q, R Horton and M Shao. 2002. Horizontal infiltration method for determining Brooks-Corey model parameters. Soil Sci. Soc. Am. J. 2002:66:1733-1740.
34. Wang Q, TE Ochsner and R Horton. 2002. Mathematical analysis of heat pulse signals for soil water flux determination. Water Resour. Res. 38:10.1029/2001WR1089.

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 17 of 24

ACCESSION NO: 0188361 SUBFILE: CRIS
PROJ NO: IOW06548 AGENCY: CSREES IOW
PROJ TYPE: HATCH PROJ STATUS: NEW MULTISTATE PROJ NO: NC-230
START: 01 OCT 2000 TERM: 30 SEP 2005 FY: 2002

INVESTIGATOR: Isenhart, T. M.; Schultz, R. C.; Menzel, B. W.; Kelly, J. M.; Mickelson, S. K.

PERFORMING INSTITUTION:
NATURAL RESOURCE ECOLOGY & MANAGEMENT
IOWA STATE UNIVERSITY
AMES, IOWA 50011

INTEGRATING BIOPHYSICAL FUNCTIONS OF RIPARIAN SYSTEMS WITH MANAGEMENT PRACTICES AND POLICIES

OBJECTIVES: The unifying objectives of this project are to provide an integrated process-based approach to understanding biophysical function within riparian zones and to determine effective riparian management practices for increasing or sustaining on-site and downstream water quality. We will explicitly address three major themes; biophysical, social, and integration of the biophysical and social components. We will initiate long-term studies to determine changes in riparian function over time, including the response time required for restored buffers to become functionally equivalent with established buffers. These objectives will culminate with our goal, that is to answer the question: What riparian management and policies will provide improved on-site practices and accumulative human benefits and protect downstream water quality while "remaining consistent" with our need to use and develop land and water resources? Specifically, the objectives of this project are to: 1. Assess biophysical functions of riparian management as they relate to management practices for increasing or sustaining on-site and downstream water quality. 2. Evaluate alternative riparian management systems in terms of cost effectiveness, water quality benefits, and adoption by land managers. 3. Develop integrated tools needed for land management and policy development, to select and enhance adoption of preferred riparian management systems.

APPROACH: Ongoing projects within the North Central Region provide the opportunity to examine the effects of riparian management practices on on-site benefits and water quality parameters. These projects will allow us to: a) examine biophysical functions of riparian management areas and land manager adoption in forest, grassland, and agricultural settings within the context of natural variation in riparian characteristics within the watershed, b) examine potential ecoregion differences in riparian areas by including watersheds that differ in geomorphic setting, stream physical characteristics, land use, and land management perception, and c) explicitly examine scale issues in riparian management by comparing site-level and landscape contributions to riparian outcomes. Specific approaches will include a regional inventory of riparian environmental conditions utilizing Gap Analysis Project (GAP) land use and vegetation databases. Gap Analysis is conducted by combining the distribution of natural vegetation with the predicted distribution of vertebrates and vegetation types as indicators of biodiversity. Sites will be stratified according to ecoregion, drainage area, etc. and data will be verified on the ground at selected riparian sites both within and nearby selected watersheds by assessing their condition with standardized protocol. To achieve the goal of collecting consistent, integrated data examining regional patterns in riparian function, project personnel will facilitate planning and coordination across current projects, sharing of equipment, pooling of data, data analysis, and summarization of findings with teams led by cooperators from MN, SD, NE, and MN. Current monitoring efforts will also be expanded to assess a consistent and a potentially broader array of on-site variables and the effects of riparian vegetation manipulation on these variables. As an integrating tool, project cooperators will involve, test, and modify as appropriate the Riparian Ecosystem Management Model. This model is specifically being developed by USDA-ARS to evaluate management alternatives in riparian areas for mitigating nonpoint source pollution. An additional goal of the project is to identify programs to enhance adoption of riparian management systems. Project cooperators will use adoption studies to help identify impediments and needed incentives in a given geographic location. These studies will compare producer willingness to adopt to water user willingness to pay (WTP) for a locally-based riparian management program. The comparison of adoption and WTP studies will result in the identification of a feasible program, including the size and composition of buffer strips and the nature of cost sharing requirements.

NON-TECHNICAL SUMMARY: The serious environmental and economic consequences of degraded riparian conditions have become prominent land management issues in the North Central Region. This project will advance our understanding of biophysical function within riparian zones of the North Central Region and determine effective management practices for increasing or sustaining on-site and downstream water quality.

PROGRESS: 2001/01 TO 2001/12
Ongoing projects within Iowa and Missouri provide the opportunity to examine the effects of riparian management practices on on-site benefits and water quality parameters. These projects are allowing us to: a) examine biophysical functions of riparian management areas and land manager adoption in forest, grassland, and agricultural settings within the context of natural variation in riparian characteristics within the watershed, b) examine potential ecoregion differences in riparian areas by including watersheds that differ in geomorphic setting, stream physical characteristics, land use, and land management perception, and c) explicitly examine scale issues in riparian management by comparing site-level and landscape contributions to riparian outcomes. One research focus area is the Bear Creek Watershed in Central Iowa, where riparian buffer has been re-established on over 11 km of stream length since 1990. One component of this research is to determine the effectiveness of an established multi-species buffer in trapping sediment, nitrogen, and phosphorus from cropland runoff. Results during natural rainfall events demonstrate that a 16.3 m wide switchgrass/woody buffer removed 97% of the sediment, 94% of the nitrate-nitrogen, 91% of the total phosphorus, and 80% of the phosphate-phosphorus. Results from groundwater investigations suggest that the water quality benefits of buffers are most dependent on geology, groundwater residence time and geochemical environment. A second research focus area is three watersheds that drain into the Mark Twain Reservoir in Monroe County, Missouri. The goal of this project is to assess the ability of riparian zones under various land-use practices to reduce non-point source pollutants. Study locations compared riparian zone processes under cropfields, pasture and forest. Intensive initial soil coring was conducted to characterize the alluvial soils and identify sampling plots at each treatment site. Soil quality characterization studies are presently being conducted on these sites, using soil aggregation, organic C, microbial biomass, and denitrification as major parameters of quality. In addition surface runoff and infiltration studies will be conducted in each of the treatment areas. As a component of this project, an investigation was conducted of the attitudes of financial professionals regarding water quality and riparian buffers using surveys, focus groups, and individual contacts. Conclusions drawn were that the professionals perceive that the main impediment to the adoption of buffer practices was financial, and that their relatively low knowledge level of buffers seems to be associated with their disinterest in discussing buffers with clients.

IMPACT: 2001/01 TO 2001/12
This research demonstrates that riparian buffers re-established on previously cropped or pastured land have tremendous potential to remediate nonpoint source pollution in agricultural ecosystems. The research also provides insight into the geomorphic, hydrologic, and biologic factors controlling the effectiveness of streamside buffers. This information is being used to improve the performance of buffers in the field and help realize the promise of conservation buffer technology.

PUBLICATIONS: 2001/01 TO 2001/12
No publications reported this period

PROJECT CONTACT:

Name: Good, C.
Phone: 515-294-4544
Fax: 515-294-2909
Email: cgood@iastate.edu

Item No. 18 of 24

ACCESSION NO: 0164317 SUBFILE: CRIS
PROJ NO: NEB-10-124 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 JAN 1994 TERM: 31 DEC 1998 FY: 1999

INVESTIGATOR: Supalla, R. J.; Allen, J. C.

PERFORMING INSTITUTION:
AGRICULTURAL ECONOMICS
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

ECONOMIC ANALYSIS OF FARM MANAGEMENT & PUBLIC POLICY ALTERNATIVES FOR IMPROVING GROUNDWATER QUALITY

OBJECTIVES: Evaluate the farm level consequences of alternative technologies and management practices for reducing groundwater pollution from irrigated agriculture. Analyze the adoption behavior of irrigated products with respect to the use of best mangement practices (BMP's) for improving water quality. Evaluate public policy alternatives for improving groundwater quality.

APPROACH: A systems approach is used to assess the economic and environmental tradeoffs associated with alternative management strategies for reducing nitrate contamination of groundwater. Farm level management alternatives will be evaluated to determine best management practices (BMP's). The types of alternatives to be considered include: crop rotations; amount, timing and method of nitrogen application; amount, timing and method of water applications; and crop monitoring technologies. Public policies for encouraging the adoption of best management practices will also be evaluated, including educational programs, incentives and direct regulations.

NON-TECHNICAL SUMMARY: Nitrate pollution of groundwater is an important environmental problem in Nebraska. This project is focused on finding least cost methods of reducing nitrate pollution of groundwater from irrigated agriculture.

PROGRESS: 1994/01 TO 1998/12
This project addressed management options for reducing nitrate pollution of groundwater, using the Central Platte valley of Nebraska as a case study area. The first major finding was that not all producers were maximizing profits and over 80 percent of producers in the region expressed a willingness to voluntarily incorporate environmental considerations in their production decisions even if it significantly reduced profits. Also, several production practices were identified which if adopted by producers would be win-win, i.e., they would increase profits and improve environmental quality. The presence of a strong environmental ethic among producers and the existence of win-win opportunities was unexpected and suggests that it may be possible to improve environmental quality through education programs without the use of conventional command and control or incentive strategies. Another major finding was that the BMP's for reducing nitrate pollution of groundwater in irrigated regions depended substantially on the current quality of the water. When irrigation water contained less than 15 mg/l of nitrate nitrogen, sprinkler irrigation with minimal water applied was the preferred management option, both economically and environmentally. With high nitrate water, however, the best economic option was well managed gravity irrigation, and the best environmental option was sprinkler irrigation applying more water than what was needed to meet evapotranspiration requirements. Precision farming, or Variable Rate Application Technology (VRAT), was evaluated as a management tool for implementing those BMP's which call for more precise management of the nitrogen and/or water input. Simulation results for several hypothetical fields that consisted of different proportions of three soils (Hord, Valentine and Platte Associations) found that VRAT increased corn yield by 9 to 26 percent, decreased water applied by 1 to 6 percent, decreased nitrogen applied by up to 22 percent and decreased nitrogen leached by up to 44 percent. Economic results suggest that producers could afford to pay from $9 to $26 per acre per year for VRAT technology and still be as well off financially as they would be using conventional practices. Estimates of the elasticity of demand for nitrogen suggest that own price elasticity has fallen from greater than -1.0 to less than -0.2, as producers have become more environmentally concerned and education programs to improve management have intensified. At an elasticity level of -0.2, it wold cost over $1.00 per pound to reduce leaching at the current use level margin. In contrast, the adoption of Best Management Practices (BMP's) was found to reduce nitrate leached at a cost of from less than zero (win-win situation ) to about $0.50 per pound. A contingent valuation and an averting cost study of willingness to pay for improved water quality in Nebraska was also conducted. Contingent valuation results indicated that consumers were willing to pay an average of $9.50 per household per month to reduce nitrate pollution to levels below the public health standard.

IMPACT: 1994/01 TO 1998/12
The primary payoffs from this research are improved water quality and increased economic returns to agriculture. These gains result from the adoption of the improved nitrogen and water management practices. Available evidence for nitrogen management indicates that irrigated producers on the average apply at least 50 pounds per acre of excess N. If only 10 percent of irrigators are induced by this research (and related programs) to reduce excess applied N by only 25 pounds per acre, it would mean an annual reduction in pollution of 10,000 tons of nitrate nitrogen and an increase in net economic returns of $3,000,000 per year.

PUBLICATIONS: 1994/01 TO 1998/12
1. Supalla, R. J., R. A. Selley, S. Bredeweg and D. G. Watts. 1995. "Factors Affecting Adoption of Practices to Improve Water Quality." Journal of Soil and Water Conservation, Jan./Feb.
2. Supalla, R. J., W. M. Miller and B. Julianno. 1996. "Linkages Between Technology Adoption Behavior in Agriculture and Environmental Policy." The Sixth International Symposium on Social and Resource Management, Pennsylvania State University, University Park, PA.
3. Supalla, R. J., S. Ahmad and R. A. Selley. 1996. "Policy Implications of Win-Win Opportunities for Improving Groundwater Quality in Irrigated Areas." Abstract, AJAE, Vo. 78, No. 5.
4. Khan, M. A. and R. J. Supalla. 1997. "Elasticity of Demand for Nitrogen: Implications for Environmental Policy." Selected Paper, Southern Agricultural Economics Association Annual Meeting, Birmingham, Alabama, February 1-5.
5. Ahmad, S. and R. J. Supalla. 1997. "Potential Economic and Environmental Returns to Variable Rate Application of Nitrogen." Selected Paper, Southern Agricultural Economics Association Annual Meeting, Birmingham, Alabama, February 1-5.
6. Ahmad, S., R. A. Selley and R. J. Supalla. 1997. "Policy Alternatives for Improving Groundwater Quality in Irrigated Areas." Selected Paper, Western Agricultural Economics Association Annual Meeting, Reno, Nevada, July 13-16.
7. Ahmad, S., R. J. Supalla and W. M. Miller. 1997. "Precision Farming for Profits and Environmental Quality: Problems and Opportunities." Poster Paper, American Agricultural Economics Association Annual Meeting, Toronto, Canada, July 27-30.
8. Juliano, B. D. 1997. "Factors Affecting Nitrogen Management Practices of Corn Producers in Nebraska." Unpublished M.S. Thesis, University of Nebraska-Lincoln.
9. Sukharomana, R. "Willingness to Pay for Water Quality Improvement: Differences Between Contingent Valuation and Averting Expenditure Methods." Unpublished Ph.D. Thesis, University of Nebraska-Lincoln, 1998.
10. Sukharomana, R. and R. J. Supalla. 1998. "Effect of Risk Perception on Willingness to Pay for Improved Water Quality." Abstract, AJAE, Vol. 80, No. 5.
11. Supalla, R. J. and S. Ahmad. 1998. "An Economic Analysis of Precision Farming as a Tool to Improve Profits and Environmental Quality." Abstract, AJAE, Vol. 80, No. 5.

PROJECT CONTACT:

Name: Supalla, R. J.
Phone: 402-472-1792
Fax: 402-472-3460
Email: rsupalla@unlnotes.unl.edu

Item No. 19 of 24

ACCESSION NO: 0133601 SUBFILE: CRIS
PROJ NO: NEB-12-173 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 05 JAN 1993 TERM: 31 DEC 1998 FY: 1999

INVESTIGATOR: Frank, K. D.; Denning, J. L.

PERFORMING INSTITUTION:
AGRONOMY
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

EVALUATING PLANT NUTRIENT NEEDS AND PRODUCT QUALITY

OBJECTIVES: 1. To cooperate with various ARD projects by providing chemical, physical & biological analyses of soil, plant & water samples. 2. Improve correlation & calibrations of soil testing methods currently available with crop response to lime & fertilizer treatment of a range of Nebraska soils. 3. Investigate & adapt new sample preparation procedures & new analytical techniques for water, plant & soil analyses. 4. Develop & update equations from correlation of NIRS analyses with wet chemistry forage & grain quality procedures.

APPROACH: 1. Maintain & operate a laboratory facility to service research projects needingelemental chemical analyses of soil, plant, water & grain & forage quality by NIRS & PSA of soils. 2. Cooperate with other research projects that generate field or greenhouse data for correlating or calibrating soil test methods with crop response or nutrient uptake. Analyze & use data from soil survey samples to refine soil test interpretation on basis of nutrient contribution of subsoil. 3. Develop & maintain NIRS equations for forage quality parameters using data from cooperating ARD & ARS projects for running both research & public samples. NIRS scans from selected research & commercial samples are equated to data from wet chemistry procedures by regression. 4. The accuracy of elemental analyses of forages & grain by NIRS/NIRT will be studied by comparing with EDXRF results.

NON-TECHNICAL SUMMARY: Rapid and accurate analysis of plant and soil nutrients is important for efficient use of nutrient resources in crop production. This project evaluated old and new methods of soil and plant analysis for accuracy and environmentally friendly methods.

PROGRESS: 1993/01 TO 1998/12
The main accomplishments during the life of this project were: 1) developed and/or improved N, P, K. Zn, S and lime recommendations for corn, wheat, sorghum, alfalfa, soybeans and pastures. 2) adapted Near-infrared Spectrometry (NIR) techniques to determine IVDMD, Crude Protein, NDF, ADF, and DM values for legume and grass hays, corn silage and feed grains. 3) Adapt NIR-T methods for predicting protein, oil, moisture, wet mill starch, and total starch for corn. 4) NIR-R and NIR-T to predict oil, protein and moisture for soybeans. 5) Develop the use of X-ray fluorescence to replace chemical digestion methods to determine, P, K, S, Cl, Mg, Mn, Zn, Fe, Cu and other minerals for plant, soil and organic amendments with success in most situations. Work is still underway to improve precision of determining, e.g., P in a mixed matrix (soil and manure mixture typical of open feedlots). 6) Investigations are underway to develop calibration and correlation equations to determine concentration of nutrients in liquid and dry fertilizers. 7) developed methods to replace chemical determination of easily oxidizable Carbon in soil by combustion (carbon/N analyzer). This involved destruction of excess lime in calcareous soils. 8) On-going collaboration with Super Critical Fluid Equipment Manufacture (ISCO) in developing extraction methods for oil and fat from grains (canola, corn, soybeans/meal and hydrocarbons from soil.) Also "energy packages" were developed for silages, haylages, and total mixed rations. Samples of canola, high oil corn and soybeans and sorghum from diverse areas are utilized to improve oil prediction equations by NIR-R and NIR-T. 9) Member of initial NIR forage analysis consortium to improve the precision of forage analysis values by NIR. 10) Collaborated with other land grant laboratories in developing North American proficiency testing program (soil and plant material). 11) Provided guidance to NE Dept of Agriculture to maintain accuracy in the NE soil and plant analysis check program for all laboratories operating in the state. 12) Cooperative study with commercial laboratories to a) develop correlation between ICP Sulfur and Ion Chromatograph determination of sulfate-S for soils; b) develop extraction techniques using Bray and Kurtz 1 to simultaneously determine Nitrate-N and phosphate-P by flow injection analysis (FIA). Continued refinement of methods for NIR-R, NIR-T and SFE will continue under normal laboratory.

PUBLICATIONS: 1993/01 TO 1998/12
No publications reported this period

PROJECT CONTACT:

Name: Cassman, K. G.
Phone: 402-472-1555
Fax: 402-472-7904
Email: kcassman1@unl.edu

Item No. 20 of 24

ACCESSION NO: 0155682 SUBFILE: CRIS
PROJ NO: NEB-12-209 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: REVISED
START: 01 OCT 2001 TERM: 31 AUG 2006 FY: 2002

INVESTIGATOR: Spalding, R. F.

PERFORMING INSTITUTION:
AGRONOMY
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

PROCEDURES FOR ASSESSING IMPACTS OF NONPOINT AGRICHEMICALS ON GROUNDWATER

OBJECTIVES: The impacts of farm scale conversions to improved herbicide management alternatives on shallow groung water quality wil be investigated at the sprinkler-irrigated MSEA site and at furrow irrigated fields in Nebraska. Changes in herbicide loading to shallow ground water will be evaluated using systems of multilevel samplers and ground water dating. Impacts of runoff and infiltration through grassed buffer strips will be investigated at the farm scale paired watersheds on the water quality in Clear Creek and on shallow ground water beneath the biffered areas. The paired watersheds will allow for comparability between herbicide loss in runoff transported through the buffered and non-buffered row cropped fields. Seven sutomatic ISCO samplers are installed at strategic points in the stream to allow for runoff monitoring of sediment, nitrate, ammonia and herbicides and their transformation products. Chemical infiltration beneath the strips will be detected with lysimeters and multilevel samplers.

APPROACH: Demonstrate performance of amended biodenitrification at a municipal well field in Wahoo, Nebraska. Multilevel samplers will be monitored to determine the degree of treatment within the denitrification zone.

NON-TECHNICAL SUMMARY: Irrigation management impacts ground and surface water quality. Ground water nitrate can be treated by in situ denitrification. This project examines the impact of management alternatives on ground water and surface water quality. This project devlops in situ aquifer methods to remediate ground water nitrate concentrations.

PROGRESS: 2001/10 TO 2002/09
Two manuscripts are now in press that may change researchers' approaches to understanding non point pesticide contamination in shallow aquifers. The data indicate that past reliance on vulnerability models using soil permeability (type), depth to ground water and irrigation to delineate areas vulnerable to pesticide contamination is oversimplified. Results from the four year monitoring study at the NE-MSEA indicate peak pesticide loading to the shallow ground water occurs prior to irrigation after intense storms in specific locations on and off cultivated fields. Recharge areas occurred in field ditches and low spots and especially in road ditches which normally surround each section. N-15 analysis of nitrate in groundwater beneath cropland fertilized with animal and meat processing lagoon wastes indicate that both heterotrophic and dissimilatory nitrate reduction to ammonia occurred. Results of the in situ biodenitrification project at Wahoo, NE municipal well field indicate that the pilot treatment was successful. Two manuscripts describing the fate and transport of ethanol and MTBE in ground water are in the final stages of polishing before submission.

IMPACT: 2001/10 TO 2002/09
A re-evaluation of the dominant mechanisms for pesticide contamination of shallow ground water is needed. Natural attenuation of nitrate occurred in areas where excessive waste applications occurred and appears responsible for keeping average ground water nitrate concentrations close to compliance levels. The successful in situ treatment of nitrate contaminated ground water at the Wahoo well field indicates that the method will provide an economic alternative for municipalities. The only available alternatives are very expensive above ground treatments.

PUBLICATIONS: 2001/10 TO 2002/09
1. Spalding,R.F., Snow, D.D., and Exner, M.E. 2002. Acetamides and their transformation products in ground water beneath Nebrsaksa's Management Systems Evaluation Area. p. 125-128. In T. Albanis (ed) Proceedings of the 2nd Europeon Conference on pesticide and related organic micropolutatants in the environment. University of Ioannina, Corfu, Greece, Sept. 26-29.
2. Exner,M.E., Harrell D., Larsen, P.L.. Romary C., and Spalding, R.F. 2002. A quality assessed database for pesticides in ground water. p.87-92.In T. Albanis (ed) Proceedings of the 2nd Europeon Conference on pesticide and related organic micropolutatants in the environment. University of Ioannina, Corfu, Greece, Sept. 26-29.
3. Snow, D.D., Cassada D.A., Monson S.J., Zhu J., and Spalding R.F. 2002. Trace analysis of tetracycline and macrolide antibiotics using solid phase extraction and liquid chromatography tandem mass spectrometry. In: Abstracts of Papers, 223rd ACS National Meeting, April 7-11. Orlando, FL.

PROJECT CONTACT:

Name: Spalding, R. F.
Phone: 402-472-8214
Fax: 402-472-9599
Email: rspalding@unl.edu

Item No. 21 of 24

ACCESSION NO: 0159768 SUBFILE: CRIS
PROJ NO: NEB-12-228 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 NOV 1992 TERM: 30 APR 1998 FY: 1999

INVESTIGATOR: Sander, D. H.

PERFORMING INSTITUTION:
AGRONOMY
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

INCREASING FERTILIZER EFFICIENCY FOR GRAIN CROPS

OBJECTIVES: 1. Increase efficiency of N and P fertilizer through improved methods of applications. 2. Improve fertilizer recommendations based on soil tests by improved soil sampling & by quantifying corn N uptake in relative to time of N application & degree of N deficiency. 3. Determine reserve capacity of Nebraska soils to supply P before yield response to fertilizer P can be effected.

APPROACH: Fertilizer efficiency will be improved by studying various methods of application in field experiments. Approaches for P will involve manipulating soil-fertilizer contact and root-fertilizer contact to maximize fertilizer uptake. Nitrogen fertilizer efficiency will be improved by studying the effect of delayed soil sampling time on the accuracy of soil test prediction of N need and by evaluating the quantitative effect of time of N application on yield increases under various degrees of N deficiency. Greenhouse and laboratory studies will be used to evaluate the long-term ability of Nebraska soils to supply P.

PROGRESS: 1992/11 TO 1998/04
Two long-term experiments were established in 1996 and 1997 to determine the fertilizer N equivalency and N mineralization of various rates of biosolids obtained from the City of Lincoln's waste treatment plant. One experiment is on continuous irrigated corn and the other on continuous dryland grain sorghum. Rates of biosolids are being applied each year to new plat areas and residual N effects determined from previous applications. N mineralization is being determined from in situ mineralization cans located in the experimental area. Soil moisture and temperature are being monitored. Data generally indicates that for irrigated corn the rate of biosolids that produced maximum yield the first year would produce 83 and 66% of maximum one and two years after applied. The biosolids rate that produced maximum yield the first year for dry land sorghum resulted in 89 and 77% of maximum one and two years after applied. At these rates the biosolids would be half as affective 1.4 years after application for irrigated corn and 1.9 years after application for dry land sorghum.

PUBLICATIONS: 1992/11 TO 1998/04
1. Sander, D.H., and B Eghball. 1999. Planting date and phosphorus fertilizer placement effects on winter wheat. Agron. J. 91:707-712.
2. Binder, D.L., and D.H. Sander. 1998. Border row effect on corn grain response to sidedressed nitrogen fertilizer. Commun. Soil Sci. Plant Anal. 29 (9&10):1349-1354.


Item No. 22 of 24

ACCESSION NO: 0168886 SUBFILE: CRIS
PROJ NO: NEB-12-244 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 05 JUL 1995 TERM: 30 JUN 2000 FY: 2001

INVESTIGATOR: Powers, W. L.

PERFORMING INSTITUTION:
AGRONOMY
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

SOIL PHYSICAL RELATIONSHIPS FOR BEST MANAGEMENT PRACTICES TOPROTECT WATER QUALITY

OBJECTIVES: A. Establish criteria for selecting best management practices (BMPs) based on soil physical relationships which affect surface and ground water quality. B. Determine the effect of present BMPs on soil physical relationships which affect surface and ground water quality.

APPROACH: To achieve objective A, the LEACHM (Leaching Estimation and Chemistry Model) will be used to develop and evaluate remediation practices (based primarily on soil physical relationships) for soils contaminated with munitions (TNT, RDX, etc). This same model along with others will be used to select irrigation regimes for turf grass. A simple technique using a sieving technique will be used to quantify the shape of soil aggregates which can effect fate and transport of agrichemicals. To achieve objective B, the effect of long-term best management practices (BMPs) for applying animal and municipal by-products to soil will be examined in light of their influence on the K factor of the Revised Universal Soil Loss equation (RUSLE) and on soil physical properties such as infiltration rate (permeability), pore size distribution, bulk density, and dry aggregate size distribution.

NON-TECHNICAL SUMMARY: NA

PROGRESS: 1995/07 TO 2000/06
The purpose of this project was to establish soil physical relationships for selecting BMPs and to examine the effect of present BMPs on soil physical relationships. This project consisted of the following four field studies: (1) Alternative production system effect on the K-factor of the Revised Universal Soil Loss Equation; (2) Soil quality assessment after weed-control tillage in a no-till wheat-fallow cropping system; (3) Soil condition as influenced by cropping and tillage systems in the Central High Plains; and (4) Spatial characterization of soil physical properties in irrigation furrows. Study (1) indicated that alternative production systems do affect the K-factor of some soil series and can reduce soil erodibility and erosion. Study (2) showed that occasional tillage with the moldboard plow in a reduced or no tillage management system for wheat will help control winter annual grass weeds without destroying the soil physical benefits of conservation tillage. Study (3) showed that the type and frequency of tillage and cropping systems do affect some soil physical properties. Water infiltration rates were affected as conventional-till (CT) systems tended to have slower intake rates than reduced-till (RT) and no-till (NT) systems. Bulk density under CT systems was greater than that under NT systems. Study (4) showed that the saturated hydraulic conductivity, bulk density, and penetrometer resistance differ significantly among each furrow in an eight-row equipment pass. However, this repeating pattern for penetrometer resistance was not significant below the six-inch soil depth.

IMPACT: 1995/07 TO 2000/06
Study (1): Alternative production systems do affect the K-factor of some soil series and should be taken into consideration when developing conservation plans. Study (2): Because occasional plowing (every 5-6 yrs or so) to control annual grasses has no detrimental long-term effect on the physical quality of soils, the adoption of this relatively inexpensive practice for no-till systems could improve the economic return from land in the High Plains of the United States. Study (3): Although the soil physical properties evaluated varied with tillage/cropping system, no one system seems superior in all aspects. Thus High Plains producers can use any of the evaluated systems as best management practices. However, soil physical properties should be monitored on an ongoing basis. Study (4): Field measurements from this study should be useful in furrow-irrigation simulation models to find environmentally favorable and less expensive water management options.

PUBLICATIONS: 1995/07 TO 2000/06
1. Kessavalou, A., J.W. Doran, W.L. Powers, T.A. Kettler, and J.H. Qian. 1996. Bromide and nitrogen-15 tracers of nitrate leaching under irrigated corn in central Nebraska. Journal of Environmental Quality. 25:1008-1014.
2. Woodbury, B.L., S.D. Comfort, and W.L. Powers. 1996. An automated sampling system for large soil column transport studies. Transactions of the American Society of Agricultural Engineers. 39:2163-2166.
3. Aslan, M., J. Skopp, and W.L. Powers. 1998. Modified proportional model for time-dependent sieving. Soil Science. 163:472-481.
4. Powers, W.L., M.L. House, R.D. Tejral, and D.E. Eisenhauer. 1999. A simultaneous data collection system for several soil water release curves. Applied Engineering in Agriculture. 15:477-481.
5. Krishnan, G., G.L. Horst, S. Darnell, and W.L. Powers. 1999. Growth and development of smooth bromegrass and tall fescue in TNT-contaminated soil. Environmental Pollution. 101:1-8.
6. Kettler, T.A., D.J. Lyon, J.W. Doran, W.L. Powers, and W.W. Stroup. 2000. Soil quality assessment after weed-control tillage in a no-till wheat-fallow cropping system. Soil Science Society of America Journal. 63:339-346.
7. House, M.L., W.L. Powers, D.E. Eisenhauer, D.B. Marx, and D. Fekersillassie. 2001. Spatial analysis of machine-wheel traffic effects on soil physical properties. Soil Science Society of America Journal. 64:Sept-Oct.

PROJECT CONTACT:

Name: Powers, W. L.
Phone: 402--472--1529
Fax: 402-472-7904
Email: wpowers@unlnotes.unl.edu

Item No. 23 of 24

ACCESSION NO: 0164320 SUBFILE: CRIS
PROJ NO: NEB-42-020 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 18 MAR 1994 TERM: 30 NOV 1999 FY: 2000

INVESTIGATOR: Kranz, W. L.

PERFORMING INSTITUTION:
NORTHEAST RES & EXTENSION CNTR
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

EFFECTS OF PREPLANT TILLAGE AND NITROGEN APPLICATION METHOD ON NITRATE LEACHING

OBJECTIVES: 1. Ascertain the influence of preplant tillage on total nitrogen leaching loss &loss via preferential flow pathways. 2. Determine the impact of nitrogen application method of leaching loss. 3. Evaluate the interaction between preplant tillage and nitrogen application for soil leaching loss. 4. Examine the distribution & continuity of preferential flow pathways using image analysis.

APPROACH: Large undisturbed soil monoliths (1 cubic meter) were excavated from field plotswith 15 years of tillage history. Soil monliths were obtained from 3 replications of 3 tillage treatments-moldboard plow + harrow, chisel, & ridgetill. Conservative tracers will be used to simulate nitrogen applied with water, surface broadcast, & slot + compaction. A rainfall simulator will apply water at a 25 mm/hr rate during 2 events. Event 1 will simulate 10 year storm for central Iowa and Event 2 will bring the total water applied to near 1.5 pore volumes. Soil water content will be monitored at 15, 20, 35, 65, and 90 cm below the soil surface using time domain reflectometry. Minitensiometers will be placed adjacent to the TDR waveguides. Readings will be recorded at 15 minute intervals throughout the simulation events. Leachate samples will be collected from a 54 cm square area on the bottom of the monolith using fiberglass wick extractors. Wick extractors will be placed in a 6 x 6 grid arrangement. Following simulation runs the soil will be disected at 10 cm intervals for video imate analysis of macropores.

NON-TECHNICAL SUMMARY: Corn producers use some preplant tillage and nitrogen fertilizer application method combinations that may contribute to nitrate leaching losses. The purpose of this project is to determine which combination of preplant tillage and nitrogen fertilizer application method minimizes nitrate leaching losses from cropland. If successful, producers can use practices that limit contamination of groundwater and surface water.

PROGRESS: 1994/03 TO 1999/11
Nitrogen application was simulated by applying conservative tracers to one meter cubic soil blocks removed from plot areas with 15 years of tillage and cropping history. Tracers were applied to simulate surface broadcast, slot with surface compaction, and with water. A fiberglass wick extraction system was used to collect leachate in a 6 x 6 square grid arrangement. Data analysis suggested that low level surface compaction was not sufficient to direct water around a tracer application zone. Water flow may need to be directed away from the application zone by mounding or doming soil over the application zone in addition to compaction over the area. Because the slot applied tracer was concentrated in a narrow band, leaching loss curves indicated greater losses directly below the application zone regardless where the greatest water losses were recorded. This means that water was not directed around the zone of application effectively. For broadcast applications, nitrate-nitrogen loss was determined by water collections at each grid cell for each water application. After block collection procedures were completed, it was determined that the field area contained soils from three mapping units. These soils have slightly different profiles that may have impacted leaching loss results.

IMPACT: 1994/03 TO 1999/11
For these soil conditions, a) Substantial soil compaction will be necessary to direct infiltrating water around a zone of chemical application. Soil mounding or doming may also be required. b) Variation in small-scale soil properties mask the impact of cultural practices even after 15 years of consistent treatments. c) Additional research is needed to verify the true impact of nitrogen application methods on nitrogen leaching.

PUBLICATIONS: 1994/03 TO 1999/11
No publications reported this period

PROJECT CONTACT:

Name: Kranz, W. L.
Phone: 402-370-4012
Fax: 402-370-4010
Email: wkranz1@unl.edu
URL: http://www.ianr.unl.edu/ianr/nerec/Bill Kranz.htm

Item No. 24 of 24

ACCESSION NO: 0164811 SUBFILE: CRIS
PROJ NO: NEB-48-023 AGENCY: CSREES NEB
PROJ TYPE: HATCH PROJ STATUS: TERMINATED
START: 01 JUN 1994 TERM: 31 MAY 2000 FY: 2000

INVESTIGATOR: Selley, R.

PERFORMING INSTITUTION:
SOUTH CENTRAL RES & EXT CENTER
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583

FORMULATION OF NITROGEN FERTILIZATION RECOMMENDATIONS TO MAXIMIZE ECONOMIC AND ENVIRONMENTAL GOALS

OBJECTIVES: 1. Provide guidance on how to formulate statewide recommendations considering producer and social objectives. 2. Study producer response to recommendations, focusing upon behavioral patterns and producer characteristics, and their influence on producer acceptance. 3. Estimate the cost of collection of site specific information, the cost of recommendation errors due to lack of site specific information, and the cost of adjusting application rates within and between sites. 4. Rank additional information that could potentially lead to refinement in nitrogen fertilization recommendations, e.g. should we be asking for past N levels, whether the land is dryland or irrigated, the type of irrigation.

APPROACH: The objectives of this project will be pursued using data from central Nebraska.It is intended to develop procedures that could be applied to a larger study area such as the State of Nebraska. Producer response to N fertilization recommendations will be studied by identifying patterns of behavior using reports of soil tests and fertilizer application rate submitted to the Central Platte NRD. Obj. 2 will be further pursued through group focus interviews and/or a survey questionnaire. Obj. 3 will be pursued with interviews of producers and dealers to determine sampling and applications costs and to develop budgets to summarize those costs. Obj. 4 will involve using EPIC, a crop simulation model for estimating N leaching and yields.

NON-TECHNICAL SUMMARY: Nitrogen fertilization of crops is profit motivated but has the risk of contamination of ground and surface water. This project seeks to identify procedures for making nitrogen fertilization recommendations that will result in application rates that balance profit and environmental risk.

PROGRESS: 1994/06 TO 2000/05
It was demonstrated that practices designed to protect and improve the groundwater should be evaluated in terms of their net impact upon the ground water. Under irrigation this means determining, for example, nitrate leaching less the nitrate removed from the aquifer through pumping. When recognizing the influence of the nitrate level in the ground water it follows that best management practices may differ depending on the level of nitrate in the ground water. It was also shown that simulating a single point in a gravity irrigated field to evaluate net nitrate leaching can lead to erroneous results. Contrary to expectations, simulation results indicate pumping in excess of crop needs using a gravity irrigation system may be most attractive economically and environmentally when the nitrate levels in the ground water are high. Irrigating for crop needs with a center pivot system is attractive when ground water nitrate levels are low. Also contrary to expectations, a corn-soybean rotation is not always superior environmentally to continuous corn evaluated based on net nitate leaching. It was found in the Central Platte river valley producers typically apply more nitrogen than is recommended when the recommendation is relatively low. However, environmentally concerned, well educated, well informed and younger producers were more likely to apply nitrogen near recommended levels.

IMPACT: 1994/06 TO 2000/05
The major impact of this research has been upon the methods used in evaluating production practices. As these procedures are implemented, best management practices will have to be formulated for the situation, both the environment, the level of understanding on the part of producers and their willingness to bear risk.

PUBLICATIONS: 1994/06 TO 2000/05
1. Zara,P, R.Selley,et.al. 1994. Simulating N Leaching in Furrow Irrigated Corn, Irrig Science. Vol 15, No 4, Dec.
2. Supalla,R, R.Selley,et.al. 1995. Analysis of Factors Affecting the Adoption of Nitrogen Management Practices fot Improving Water Quality. J. of Soil and Water Conservation. Jan-Feb.
3. Selley. R. and P. Wilson. 1997. Risk Research and Public Outreach: A Tale of Two Cultures?. J of Agricultural and Resource Economics, 22(2):222-232.
4. J. Cahoon, R.Selley, et. al. 1999. Corn yield Response to Tillage with Furrow Irrigation. J of Production Ag, Vol 12, No2, Apr-Jun.

PROJECT CONTACT:

Name: Selley, R. A.
Phone: 402-762-3535
Fax: 402-762-4422
Email: RSelley1@unl.edu