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Item No. 1 of 9ACCESSION NO: 0170088 SUBFILE: CRIS
INVESTIGATOR: Schultz, R. C.; Isenhart, T. M.; Raich, J. W.; Simpkins, W. W.
IOWA STATE UNIVERSITY
AMES, IOWA 50011
IMPROVING SOIL AND WATER QUALITY WITH A MULTI-SPECIES RIPARIAN BUFFER STRIP
OBJECTIVES: 9501579. Our specific project objectives are: 1) to demonstrate the effectiveness of a constructed multi-species riparian buffer strip system (CMRPBS) in retaining and/or transforming nitrate in vadose zone and shallow ground waters; 2) to evaluate mechanisms of nitrate retention and transformation within the CMRBS by: a) assessing rates of denitrification and the potential for denitrification as affected by vegetation and soil properties, b) assessing the importance of plant immobilization of nitrogen in different vegetation types, and c) assessing the importance and potential of microbial immobilization of nitrate. 3) to quantify soil quality parameters potentially regulating water movement, microbial activities, and overall rates of nitrate transformation, and to investigate their relationships to vegetation cover.
APPROACH: These goals will be achieved through intensive sampling and experimental approaches focused on artificial buffer strips in central Iowa. These sites have been the focus of research by the Iowa State Agroforestry Research Team for the past four years and background data on water and agricultural chemical fluxes, and on rates of plant establishment in the buffer strips, provides a valuable information base upon which we will build. We will measure rates of denitrification, potential denitrification activity, N immobilization in above-and belowground plant materials, potential rates of microbial nitrate immobilization, and soil quality characteristics (Bulk density, infiltration rates, rooting depths, organic matter contents, C:N ratios) in each of three replicates of each of three transects in each of two different types of streamside buffer strips. The CMRBs consists of fast-growing trees placed closest to the stream, then several rows of shrubs, and a wide strip of native grasses established next to the agricultural field. This 20 m-wide buffer strip is being compared to a cool season grass buffer strip of the same width. Study results will be integrated using the soil-plant ecosystem model CENTURY.
PROGRESS: 1995/09 TO 1999/08
A sixteen-meter-wide multi-species riparian buffer was planted in 1990 consisting of 5 rows of trees adjacent to the stream, 2 rows of shrubs adjacent to the trees and a 7-meter-wide strip of native warm-season grass between the shrubs and cropfield. Seven years after establishment the buffer removed 95% of the sediment, 94% of total-N, 85% of nitrate nitrogen, 91% of total-P and 80% of phosphate phosphorus from surface runoff. Total soil carbon increases since the buffer establishment were 123% under trees, 85% under switchgrass and 61% under cool-season grasses. Particulate organic matter showed similar increases. Fine root and microbial biomass were three times higher in buffer soil than in crop soil. As a result, soil respiration rates were twice as high in the buffer soil as in the crop soil. Soil infiltration rates under the buffer were four times as high as in crop soils. Nitrate in the soil water of the unsaturated zone was reduced by up to 90% as it crossed through the buffer. Four years after establishment, denitrification rates in the soil under trees were significantly higher than in crop soil, but rates under switchgrass were not different from the crop soil. After seven years the denitrification rates under both trees and switchgrass were more than four times higher than in the crop soil and not significantly different from those in soil under cool-season grass. Removal of nitrate from the groundwater depends on the hydrogeologic setting of the aquifer. In this project, 10-15% of the nitrate was removed from the groundwater, mainly near the water table. In thinner aquifers, up to 90% of the nitrate might be removed. Nitrate removal seems limited by available carbon in the groundwater, and work has been started to assess the production of dissolved organic carbon under different plant communities. People in the Bear Creek watershed 1) want clean surface and ground water, 2) perceive that multi-species riparian buffers are acceptable and functional best management practices (BMPs), and 3) are willing to pay for improvements in surface water quality. Landowners in the Bear Creek watershed rated the 1993 surface water quality at a 6.0 (on a 0 to 10 water quality ladder scale with 10 representing best quality for human use). They wanted to improve the surface water quality to 8.3. This represents an improvement of over 30%. To achieve this improvement they perceive that > 50% reductions in sediment, fertilizer and herbicide pollutants are required. In 1993, landowners (farmers and non-farmers) were willing to pay ~ $48 per year to improve surface water quality. A 1997 focus group of farmers indicated a willingness to pay (WTP) of $25 per year to improve surface water quality. Bear Creek landowners believe that a mix of upland (field) BMPs and riparian buffers will improve water quality the most. Considering the Bear Creek watershed and a 20-year WTP present value (@5% and $48 per year) of $610,000, a 10 to 20 m wide buffer could be placed along the entire stream on both sides. Such a buffer would provide additional non-market goods and services such as hunting and aesthetics, which are highly valued by landowners.
IMPACT: 1995/09 TO 1999/08
Buffers developed in this project have served as a template for the NRCS Riparian Forest Buffer Conservation Standard - 392 that is being applied along streams nationwide. The research has demonstrated that the buffers can significantly reduce non-point source pollution from cropfields and pastures. Landowners value these buffers and have shown strong support for their installation.
PUBLICATIONS: 1995/09 TO 1999/08
1. Johnston, D.A. 1998. Hydrogeology and geology of three restored riparian buffers near Roland, Iowa. M.S. Thesis. Iowa State University.
2. Andress, R.J. 1999. Fate and transport of nitrate in groundwater within a riparian buffer in the Bear Creek watershed. M.S. Thesis. Iowa State University.
3. Lee, K.H. 1999. Effectiveness of a multi-species riparian buffer system for sediment and nutrient removal. Ph.D. Dissertation. Iowa State University.
4. Lee, K.H., Isenhart, T.M., Schultz, R.C. and Mickelson, S.K. 1999. Nutrient and sediment removal by switchgrass and cool-season grass filter strips in Central Iowa, USA. Agroforestry Systems 44:121-132.
5. Marquez, C.O., Cambardella, C.A., Isenhart, T.M., and Schultz, R.C. 1999. Assessing soil quality in a riparian buffer by testing organic matter fractions in central Iowa, USA. Agroforestry Systems 44:133-140
6. Pickle, J. 1999. Microbial nitrate immobilization in a multi-species riparian buffer. M.S. Thesis. Iowa State University.
7. Szymanski, M. and Colletti, J. 1999. Combining the socio-economic-cultural implications of community owned agroforetry: the Winnebago Tribe of Nebraska. Agroforestry Systems 44:227-239.
8. Tufekcioglu, A., Raich, J.W., Isenhart, T.M., and Schultz, R.C. 1999. Root biomass, soil respiration, and root distribution in crop fields and riparian buffer zones. Agroforestry Systems 44:163-174.
9. Schultz, R.C., Isenhart, T.M., Colletti, J.P., and Marquez, C.O. 2000. Integrated riparian management systems to protect water quality. Chapter 7 in B. Rietveld and G. Garrett (eds.) Agroforestry: An integrated Science and Practice. American Society of Agronomy, Inc., Madison, WI. USA (In press).
Name: Good, C.
Item No. 2 of 9ACCESSION NO: 0175554 SUBFILE: CRIS
INVESTIGATOR: Harrison, R. L.
IOWA STATE UNIVERSITY
AMES, IOWA 50011
THE BASEMENT MEMBRANE AS A BARRIER TO BACULOVIRUS DISSEMINATION IN THE HOST
OBJECTIVES: 9702936. The objectives of the proposed research are (1) to evaluate the extent to which insect basement membranes inhibit the infection of host insect tissues by baculoviruses, and (2) to determine if degradation of the basement membranes will enhance the pesticidal potential of baculoviruses.
APPROACH: Recombinant Autographa californica MNPV baculoviruses will be constructed which express genes encoding proteases that degrade basement membrane proteins. To determine if enhancement of systemic infection occurs with the expression of basement membrane-degrading proteases, larvae of the tobacco budworm, Heliothis virescens, will be infected with wild-type and protease-expressing viruses and systemic infection will be measured both by in vitro and in vivo methods. I will then construct a recombinant virus which expresses both the insect-selective scorpion toxin AaIT and the protease which promotes the highest level of systemic infection in H. virescens larvae. The insecticidal efficacies of this virus and of wild-type virus and viruses that express the protease or AaIT alone will then be measured by bioassay and determination of the extent of feeding damage caused by infected larvae.
PROGRESS: 1997/08 TO 2000/12
The goal of this project was to optimize the pesticidal potential of baculoviruses by targeting the host basement membrane, which is a potential barrier to secondary infection of host tissues. We produced recombinant clones of the baculovirus Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV) that expressed one of three genes for proteases that degrade basement membrane proteins. One of these viruses (AcMLF9.ScathL) killed Heliothis virescens larvae significantly faster than wild-type AcMNPV in survival time bioassays. This virus also killed larvae significantly faster than recombinant AcMNPV expresssing the AaIT and LqhIT2 scorpion toxins. To determine if simultaneous expression of a protease and a scorpion toxin within the host would have an additive or synergistic effect on speed of kill, survival time bioassays were set up in which neonate H. virescens were infected with mixtures of protease viruses and AcMLF9.LqhIT2, a recombinant virus that expresses the LqhIT2 scorpion toxin. The mixed infections resulted in survival times that were not significantly different than that achieved with either AcMLF9.LqhIT2 by itself or (in those cases where the mixed infection included AcMLF9.ScathL) AcMLF9.ScathL by itself. Feeding damage assays were carried out to assess the reduction in feeding by virus-infected larvae caused by expression of ScathL. H. virescens neonates infected with AcMLF9.ScathL consumed significantly less lettuce than larvae infected with wild-type AcMNPV. Although AcMLF9.ScathL kills H. virescens significantly faster than AcMLF9.LqhIT2, no signicant difference in the amount of feeding by H. virescens larvae infected with these two viruses was observed. AcMLF9.ScathL caused extensive premature cuticular melanization in 5th instar Heliothis virescens and also some melanization of internal tissues. A considerable amount of fragmentation of internal tissues was also observed in larvae infected with AcMLF9.ScathL. These observations are consistent with destruction of host basement membranes by the expressed proteases, followed by the melanotic encapsulation of tissues that have a damaged or missing basement membrane (a phenonomenon previously observed in the fruit fly, Drosophila melanogaster) and the reduction of tissue integrity. Currently, recombinant baculoviruses that express scorpion toxins are considered to have greatest potential for deployment as pest control agents. The results from our studies suggest that viruses that express basement membrane-degrading proteases may function better than toxin-expressing viruses for control of insect pests. Although some observations suggest that the basement membrane is being degraded in insects infected with AcMLF9.ScathL, there is no direct evidence for this at this time. The precise mechanism by which ScathL reduces survival time of infected larvae is also currently unknown.
IMPACT: 1997/08 TO 2000/12
With the execution of the Food Quality Protection Act, growers are faced with the loss of a number of chemical insecticides. In addition, public anxiety about genetically modified crops may result in a reassessment of the use of plants engineered with insect resistance genes. Therefore, there is an urgent need for additional insect control measures. Baculoviruses are environmentally safe alternatives to chemical insecticides that can fill this need. However, the utility of baculoviruses as control agents is hindered by the amount of time after infection that is required to kill or incapacitate infected insects. The work described above is part of an effort to improve the insecticidal activity of baculoviruses by accelerating their speed of kill with a class of enzymes that break down barriers to the progression of viral infection. The results so far indicate that the use of these enzymes can significantly improve baculovirus speed of kill. The success of this effort will pave the way for the widespread use of baculoviruses to control lepidopteran pests, which in turn will reduce the growers dependence on chemical insecticides and provide a viable alternative to transgenic crops.
PUBLICATIONS: 1997/08 TO 2000/12
1. Harrison, R.L. and B.C. Bonning. 2001. Use of proteases to improve the insecticidal activity of baculoviruses. Biological Control 20, in press.
2. PATENTS/INVENTIONS: Harrison, R.L. and B.C. Bonning. 2000. Basement membrane degrading proteases as insect toxins and methods of use for same. Filed July 12, 2000. Serial No. 09/614,789.
Name: Good, C.
Item No. 3 of 9ACCESSION NO: 0175854 SUBFILE: CRIS
INVESTIGATOR: Thornburg, R. W.
BIOCHEMISTRY, BIOPHYSICS AND MOLECULAR BIOLOGY
IOWA STATE UNIVERSITY
AMES, IOWA 50011
SELECTION OF MUTATIONS IN UNDEFINED, COMPLEX BIOCHEMICAL PATHWAYS
OBJECTIVES: 95000801. The objective of this work is to understand the mechanismsthat control the wound-response in plants. To accomplish this, we have chosen a genetic approach to characterize Arabidopsis thaliana plants unable to respond to wounding. Plants will be selected on fluorocytosine by failure to express a wound-inducible selectable marker.
APPROACH: We will examine an alternative negative selection scheme based upon cytidine deaminase. For these studies we will: A) contstruct a reverse selectable marker in which the wound-inducible pin2 promoter is linked with the E. coli codA gene (pin2-codA). B) transform Arabidopsis thaliana pin2-codA construct and select for plants which grow in the presence of fluorocytosine. C) characterize plants with respect to wound-induction and expression of the selectable marker gene.
PROGRESS: 1997/09 TO 1999/08
The cytosine deaminase coding sequence was linked with the pin2 promoter and terminator to form the construct pRT349. Arabidopsis plants were transformed. Plants with multiple copies of the transgene were selected. Plants were characterized for expression of cytosine deaminase. The pin2-codA transgene was expressed analogously to the pin2 gene in potato plants. We next developed a seedling expression system, thereby completing the goals of objective one of our previous proposal. We next demonstrated the proof of principle, that fluorocytosine is not toxic to plants, that fluorouracil is toxic to plants and that expression of cytosine deaminase in the presence of fluorocytosine is toxic to plants. Next we bulked seed from our transgenic plants and mutagenized them. M2 seed were collected and plated on selective media. Four plants survived the two rounds of screening and each had lost the wound-inducible cytosine deaminase activity, thereby completing the goals of our second experimental objective.
IMPACT: 1997/09 TO 1999/08
Every year farmers use millions of pounds of lethal insecticides in combating plant herbivores and other pests. The strategy we are using is designed to understand the molecular mechanisms that plants naturally use to successfully defend themselves against insect attack. Our strategy is designed to produce mutant plants that have lost the ability to respond to insect attack. By characterizing these mutants we expect to learn how plant defenses naturally function. The goal is to replace the use of lethal insecticides with methods to defend plants with their own natural defenses.
PUBLICATIONS: 1997/09 TO 1999/08
1. Santoso, D. and Thornburg, R.W. (1998) UMP synthase is transcriptionally regulated during pyrimidine starvation in Nicotiana plumbaginifolia. Plant Physiol. 116:815-821.
2. Zhou, L. Lacroute, F. and Thornburg, R.W. (1998) Cloning, Expression in Escherichia coli, and Characterization of Arabidopsis thaliana UMP/CMP Kinase. Plant Physiol. 117:245-254.
3. Weers, B. and Thornburg, R.W. (1998) Characterization of the cDNA and gene encoding the Arabidopsis thaliana. AMP kinase (AF082882). Plant Physiol. 118:711.
4. Zhou, L. and Thornburg, R.W. (1998) Site Specific mutagenesis of conserved residues in the phosphate binding loop of the Arabidopsis UMP/CMP kinase alter ATP and UMP binding. Arch. Biochem. Biophys. 358:297-302
5. Thornburg, R.W., Park, S., Caviedes, M., Santoso, D. and Zhou, L. (1998) Selection of mutants in complex, undefined biochemical pathways: Application of new technology to the wound-induction pathway in plants. Proceedings of the International Symposium on the Future and Development towards the 21st Century. Taegu University November 27-28, 1998 pp. 81-97.
6. Weers, B. and Thornburg, R.W. (1998) Characterization of the cDNA and gene encoding the Arabidopsis thaliana. GDP-mannose pyrophosphorylase (AF076484). Plant Physiol. 118:1101.
7. Zhou, L. and Thornburg, R.W. (1999) Wound-inducible genes in plants in Inducible Gene Expression in Plants. Reynolds, P, Ed. CAB International, Wallingford, UK 127-167.
8. Weers, B. and Thornburg, R.W. (1999) Characterization of the cDNA and gene encoding an Arabidopsis thaliana. Uracil Phosphoribosyltransferase (AF116860). Plant Physiol. 119:1567.
9. Kafer, C. and Thornburg, R.W. (1999) Pyrimidine Metabolism in Plants. Paths to Pyrimidines. 5:7-19.
Name: Good, C.
Item No. 4 of 9ACCESSION NO: 0176951 SUBFILE: CRIS
INVESTIGATOR: Tim, U. S.; Kanwar, R. S.; Batchelor, W.; Babcock, B. A.; Mallarino, A.
AGRI & BIOSYSTEMS ENGINEERING
IOWA STATE UNIVERSITY
AMES, IOWA 50011
INTEGRATED ASSESSMENT OF ENVIRONMENTAL AND ECONOMIC IMPLICATION OF PRECISION FARMING ON CROP PRODUCTION
OBJECTIVES: 9703966. Our research goals will be evaluated by the following specific aims: to collect data for evaluating the effects of variable rate application of fertilizer and atrazine herbicide on water quality; to develop methods to quantify the spatial distribution of cup yields and the impact of variable rate application on chemical losses to surface and groundwater; to evaluate the economic consequences of precision-farming and variable rate technology so that farmers can make informed management decisions.
APPROACH: This study will collect soil and water quality data at the Northeast Research Farm in Nashua to facilitate determination of variable rate application of nitrogen (N) and atrazine on leaching and runoff losses, uptake of N, and crop yields. Methods will be developed to characterize the spatial distribution of crop yields and the quantitative assessment, the Root Zone Water Quality model will be linked with a GIS to enable characterization and display of the spatial distribution of crop yield and chemical losses under site-specific chemical management. The study will also develop trade-off frontiers and measure the economic inputs to more site-specific and precise management, net farm returns change, and the need to identify the critical amounts of variability that justify a given level of investement invariable rate technology increases. Overall, the approaches used and data collected in this project will make a significant contribution to improved understanding of the economic and egronomic, and water quality benefits of precision farming.
PROGRESS: 1997/11 TO 2002/11
In this project, a systems approach was used to evaluate the agronomic, environmental, and economic implications of precision agriculture. A comprehensive problem-solving and decision-support system that improves analyses, simulation and visualization of field-scale impacts of precision agriculture practices (e.g, variable rate nutrient and pesticide management) on environmental quality and productivity has been developed and tested. The system combines biophysical modeling provided by RZWQM and CEREES-Maize models, (RZWQM 98), S-PLUS, and ArcView GIS. Components of the system have been validated and AgLink for Windows SSToolbox and many other programs. The problem solving environment decision support system also features an economic analysis component that provides risk-based estimates and trade-offs of effects of variable rate nutrient application on productivity and profitability of the farm operations. The problem-solving environment/decision support system is used to assess different options for implementing site-specific and nutrient and pesticide management practices. The modeling environment has been used to assess different combinations of climate, landscape, and management regimes on the agronomic and environmental benefits of precision agriculture.
IMPACT: 1997/11 TO 2002/11
The significance of this research to production agriculture is threefold. First, it enables us to move beyond the lumped treatment of ecological processes in agricultural fields and creates an integrated approach needed to facilitate the evolution towards site-specific management of crop production inputs. Second, it addresses the research needs articulated in the 1997 National Research Council on the scientific basis of precision agriculture. Third, the integrated decision support system significantly improves the use of computer models and the evaluation of "What if" scenarios to elucidate the optimal combination of soil, crops chemicals, terrain, and weather that enhances farm productivity and reduces off-site environmental impacts on a site-specific basis.
PUBLICATIONS: 1997/11 TO 2002/11
1. Tim US and X Wang. 1999. Integrated Spatial Decision Support System for Precision Resource Management. Proceeding of Conference on Geosolutions: Integrated Our World, GIS '99, March 1-4, Vancouver, BC, Canada.
2. Wang X and US Tim. 2003. Mining Factor Effects on Spatial Structure of Corn Yield. Journal of Agricultural, Biological and Environmental Statistics (in press).
3. Wang X and US Tim. 2003. Evaluating the environmental and agronomic implications of variable rate nitrogen management. Transactions of the ASAE (in press).
4. Tim US. 2003. Precision Agriculture and Water Quality. Encyclopedia of Agricultural, Food and Biological Engineering. New York, NY: Marcel Dekker, Inc.
5. Warnemuende EA and RS Kanwar. 2002. Effects of swine manure application on bacterial quality of leachate from intact soil columns. Transactions of the American Society of Agricultural Engineers 45(6):1849-1857
6. Bakhsh A, RS Kanwar, TB Bailey, CA Camberdella, DL Karlen and TS Colvin. 2002. Cropping systems effects on NO3-N loss with subsurface drainage water. TRANSACTIONS of the American Society of Agricultural Engineers 45(6):1789-1797.
7. Chung S, PW Gassman, R Gu and RS Kanwar. 2002. Evaluation of EPIC for assessing tile flow and nitrogen losses for alternative agriculture management systems. Transactions of the American Society of Agricultural Engineers 45(4):1135-1146.
8. Ella VB, SW Melvin, RS Kanwar, L Jones and R Horton. 2002. Inverse three-dimensional groundwater modeling using finite difference method for recharge estimation in a glacial till aquitard. Transactions of the American Society of Agricultural Engineers 45(3):703-715.
9. Chinkuyu AJ, RS Kanwar, JC Lorimor, H Xin and TB Bailey. 2002. Effects of laying hen manure application rate on water quality. Transactions of the American Society of Agricultural Engineers 45(2):299-308.
Name: Good, C.
Item No. 5 of 9ACCESSION NO: 0174285 SUBFILE: CRIS
INVESTIGATOR: Wise, R. P.; Bush, A. L.
IOWA STATE UNIVERSITY
AMES, IOWA 50011
GENETIC AND PHYSICAL ANALYSIS OF RESISTANCE TO CROWN RUST INAVENA
OBJECTIVES: 9600735. Develop recombinant inbred populations segregating for rust resistance.Position additional molecular markers tightly linked to R345 in the D526 rust resistance population via high resolution genetic analysis. Establish the degree of microsynteny of rice Bacterial Artificial Chromosomes (BAC) with the R345 rust resistance region in the D526 population and attempt to establish physical linkage of R345 with tightly-linked molecular markers.
APPROACH: We have developed a number of diploid and hexaploid mapping populations and derived recombination inbreds. These mapping populations will be used to map additional crown rust resistance loci. We will utilize high-resolution genetic analysis, microcolinearity among cerreal crops, and PCR-based amplification of resistance gene homologues to initiate positional-based cloning of genes for resistance to rust. Knowledge gained from in-depth analysis will enable us to design compound resistance gene clusters to control rust diseases. Furthering our understanding of these complex genetic interactions will be an asset in breeding programs, alleviating the problems associated with genetic uniformity and susceptibility to new races of pathogens.
PROGRESS: 1996/11 TO 1999/10
Avena (oat) plants with the appropriate genotype frequently respond to P. coronata by eliciting hypersensitive (HR) cell death at the sites of fungal infection. To investigate the genetic and cellular basis for this response, the Wise group (Corn Insects and Crop Genetics Research Unit, Ames, IA) analyzed the segregation of HR cell death on the A. strigosa (C.I. 3815) x A. wiestii (C.I. 1994) recombinant inbred (RI) population. Two newly described loci mediate HR cell death; rdh (resistance dependent hypersensitive cell death) is recessive and mediates response in resistant plants infected with P. coronata isolate 276, and, Rih (Resistance independent hypersensitive cell death) is dominant and mediates response in both resistant and susceptible plants infected with P. coronata isolate 290. These results indicate that HR cell death is not essential for resistance to crown rust and that multiple independent pathways play a role in defense to this disease. To effectively utilize current and future maps for positional cloning of agronomically important genes in Avena, a significant increase in marker density is necessary. The Wise group (Corn Insects and Crop Genetics Research Unit, Ames, IA) used two PCR (polymerase chain reaction) based methods, AFLP (amplified fragment length polymorphisms) and S-SAP (sequence-specific amplification polymorphisms) to establish a saturated map for the A. strigosa x A. wiestii RI population. Five hundred and thirteen markers were mapped to seven linkage groups, creating a framework for public utilization. This is the first saturated AFLP map created for the diploid oat genome, and provides a foundation upon which further gene-isolation efforts will be based.
IMPACT: 1996/11 TO 1999/10
Worldwide, rust diseases pose a substantial challenge to the production of small grains. The primary method of control is through genetic resistance. Host-plant resistance is the most desirable control strategy because it can be highly effective, is environmentally benign, and requires little or no additional expense to producers. This research enables breeders to utilize resistance more effectively.
PUBLICATIONS: 1996/11 TO 1999/10
1. Bush, A. L. and Wise, R. P. 1998. High-resolution mapping adjacent to the Pc71 crown-rust resistance locus in hexaploid oat. Molecular Breeding 4:13-21.
2. Kianian, S. F., Fox, S. L., Groh, S., Tinker, N., O'Donoughue, L. S., PJ Rayapati, P. J., Wise R. P., Lee, M., Sorrells, M. E., Tanksley, S. D., Fedak, G., Molnar, S. J., Rines, H. W., and Phillips, R. L. Molecular marker linkage maps in diploid and hexaploid oat (Avena sp.). DNA-based markers in plants', July 2000. 2nd edition (in press).
3. Yu, G. X. and Wise, R. P. 2000. An anchored AFLP and retrotransposon-based map of diploid Avena. Genome 43:736-749.
Item No. 6 of 9ACCESSION NO: 0193350 SUBFILE: CRIS
INVESTIGATOR: Emerich, D.
UNIVERSITY OF MISSOURI
COLUMBIA, MISSOURI 65211
18TH NORTH AMERICAN CONFERENCE ON SYMBIOTIC NITOGEN FIXATION AND THE 20TH ANNUAL MISSOURI SYMPOSIUM
OBJECTIVES: The objective is to provide a highly interactive forum in which to discuss and disseminate the recent progress in symbiotic nitrogen fixation. The meeting is the 18th North American Conference on Symbiotic Nitrogen Fixation, which is being hosted by the University of Missouri Interdisciplinary Plant Group and also serves as the 20th Annual Missouri Symposium. Both meetings have become internationally attended meetings. While the North American Conference on Symbiotic Nitrogen Fixation has a specific topic, the Annual Missouri Symposium has had varied and timely topics in plant biology. The First Annual Missouri Symposium featured symbiotic nitrogen fixation. Symbiotic nitrogen fixation has held a central position in plant biology as nitrogen is the most limiting nutrient in plant growth and development, with the occasional exception of water. Nitrogen fixation, which is performed by a rather small group of bacteria, promotes plant growth, development and ultimately species perpetuation through the formation of plant-bacterial interactions. These symbiotic interactions occur in a myriad of forms each with its own complexities. The development of symbiotic nitrogen fixation is perhaps the most sophisticated example of inter-species co-evolution. It is a highly regulated and integrated process that has significantly influenced the genomes of each symbiotic partner. We are just beginning to unravel the molecular complexities in terms of co-coordinated gene regulation, proteomic and metabolic interactions. The recent and pending publication of genomes of several nitrogen-fixing bacteria and their plant hosts provides an impetus for new avenues of research. In addition to the basic scientific intrigues of the symbiotic interaction between genomes, proteomes and metabolic systems, nitrogen fixation has a direct influence on the ecology and the environment. The application of fertilizer nitrogen influences the soil ecology and becomes an environmental pollutant since a considerable portion is leached from the soil and enters streams, lakes and waterways. Symbiotic nitrogen fixation allays the ecological and environmental concerns in agricultural systems growing leguminous crop plants. But farmers often apply nitrogen fertilizers to leguminous crop plants because effective symbioses are not always established under field conditions. Thus, there are several research areas within the overall label of symbiotic nitrogen fixation that need to be addressed to understand the fundamental molecular processes, physiology and ecology for the ultimate goal of improving agricultural productivity. The conference will subdivide the field of symbiotic nitrogen fixation into six topic areas: Genomics, Differentiation and Regulation; Physiology and Metabolism; Ecology; Agricultural and Environmental Applications; Plant-Microbial Signaling; Taxonomy and Evolution; and Other Nitrogen-Fixing Systems. There is considerable overlap among these six topic areas as symbiotic nitrogen fixation has been demonstrated to be an exceedingly complex and interdependent process.
APPROACH: Both the North American Conference on Symbiotic Nitrogen Fixation and the Annual Missouri Symposium have similar philosophies on the selection of speakers. The North American Conference on Symbiotic Nitrogen Fixation has always encouraged and featured oral presentations by junior scientists, which includes graduate students, post-doctorates and even laboratory technical staff when appropriate. The North American Conference on Symbiotic Nitrogen Fixation has always invited specific speakers in each of the topic areas, but has invited only a limited number. The remainder of the speakers are volunteers, that is, everyone who attends is permitted the choice of an oral or poster presentation. The advisory committee has in many instances encouraged a graduate student or post-doctorate to present an oral presentation rather than a poster presentation. The oral presentation affords the junior scientist a better opportunity for future scientific employment and success. The typical scientific session will contain the oral presentation by at least one post-doctorate and/or graduate student. Many conferences permit oral presentations by only established investigators. The North American Conference on Symbiotic Nitrogen Fixation promotes junior scientist oral presentations. Thus, our list of invited speakers is relatively short. This affords us maximal flexibility in selecting junior scientists for oral presentations. The Annual Missouri Symposium also has a tradition of providing an opportunity to junior faculty and post-doctorates the privilege of an oral presentation. The venue will be the Annual Symposium Series of the University of Missouri's Interdisciplinary Plant Group, but will use the format primarily of the North American Conference on Symbiotic Nitrogen Fixation blended with the traditional aspects of the Annual Missouri Symposium. The meeting will begin on Monday evening with an overview presentation by Professor Gary Stacey, who has recently accepted an endowed chair position at the University of Missouri. After the presentation there will be a reception in the poster area to initiate interaction among the meeting's participants. The meeting sessions will begin on Tuesday morning and continue until Saturday afternoon concluding with a banquet Saturday evening. Each session will include oral presentations by invited speakers, established scientists, and junior scientists, which includes graduate students and post-doctorates. Each session will include considerable time for questions from the floor. In addition, the posters will be displayed throughout the meeting. We intend to have two session completely devoted to posters. Several social events are being planned for the evening meals which will further interaction among the participants.
NON-TECHNICAL SUMMARY: The meeting is the 18th North American Conference on Symbiotic Nitrogen Fixation, which is being hosted by the University of Missouri Interdisciplinary Plant Group and also serves as the 20th Annual Missouri Symposium. Symbiotic nitrogen fixation has held a central position in plant biology as nitrogen is the most limiting nutrient in plant growth and development, with the occasional exception of water. Nitrogen fixation, which is performed by a rather small group of bacteria, promotes plant growth, development and ultimately species perpetuation through the formation of plant-bacterial interactions. These symbiotic interactions occur in a myriad of forms each with its own complexities. The development of symbiotic nitrogen fixation is perhaps the most sophisticated example of inter-species co-evolution. The conference will subdivide the field of symbiotic nitrogen fixation into six topic areas: Genomics, Differentiation and Regulation; Physiology and Metabolism; Ecology; Agricultural and Environmental Applications; Plant-Microbial Signaling; Taxonomy and Evolution; and Other Nitrogen-Fixing Systems. There is considerable overlap among these six topic areas as symbiotic nitrogen fixation has been demonstrated to be an exceedingly complex and interdependent process. The conference will bring together scientists from about a dozen foreign countries as well as many from the United States. The conference will promote the careers of young scientists by using NRICGP-USDA support to offset their costs for attending the meeting.
Name: Emerich, D.
Item No. 7 of 9ACCESSION NO: 0169476 SUBFILE: CRIS
INVESTIGATOR: Kitchen, N. R.; Sudduth, K. A.; Borgelt, S.
SCHOOL OF NATURAL RESOURCES
UNIVERSITY OF MISSOURI
COLUMBIA, MISSOURI 65211
SITE-SPECIFIC FERTILIZER RECOMMENDATION METHODS TO IMPROVE NUTRIENT UTILIZATION
OBJECTIVES: PROJ. #9501564. Proposed research objectives are: (1) Develop a method for integrating soil-landscape-, yield-, and sensor-mapped information to enable interpretation of field-scale variability dynamics in grain crop production and to obtain site-specific fertilizer management plans; (2) Implement these site-specific management plans; (3) Evaluate and compare crop growth, nutrient utilization, grain production, and profitability between site-specific and conventional fertilizer management systems; and (4) Create a user-friendly decision aid to guide ag professionals, consultants, and producers in developing site-specific fertilizer plans.
APPROACH: This project provides a framework for systematic analysis of multiple soil and landscape factors that impact crop production. Factors that impact yield that have management options for when less than optimal conditions exist will be analyzed separately from those factors in which there are no reasonable management options. The developed method will be field-scale tested on Missouri claypan soils in 1996 and 1997. We expect site-specific fertilizer plans developed from this method to refine fertilizer recommendations and result in improved crop nutrient utilization. Increased crop utilization with precise fertilizer applications will reduce the potential of nutrient impairment to water resources.
PROGRESS: 1995/09 TO 1999/02
The objective of this research was to develop nutrient management plans more precise than those currently used. The improved method tested with this research took into account the fact that the fertilizer response curve appropriate for use in a field or even a sub-field area might be significantly different than the general statewide response curve. Variable-rate N, P, K, and lime plans were developed for two claypan soil fields in Missouri. Fields were yield mapped, grid- soil sampled, topography surveyed, and topsoil-depth surveyed (using soil electrical conductivity (EC)). Evaluation of fertility measurements was conducted on sub-field areas delineated by relative elevation and topsoil depth to develop fertilizer recommendations. The relationship of yield to other spatial measurements on a whole field and a sub-field basis was tested using correlation and complex nonparametric regression. For both fields, only a single year of yield data was available for which the variable plan was developed. In both cases, yield variations were most highly related to topsoil depth variations. For fertilizer inputs that were controlled based on soil testing, it was not possible to conclude that sub-field or field-specific responses were different than the general response algorithms. Therefore, application plans were developed based on the grid-sampled data and the general algorithms. The procedure for variable-rate N applications on claypan soils was developed from previous work on other claypan soil fields. Topsoil thickness was used to predict target yield and to adjust N accordingly (target yield = 6083 + 54x; x is topsoil thickness in cm). Fields were planted using site-specific management (SSM), with embedded strips of conventional management (CM) for comparison. Because of the "maintenance plus build-up" philosophy at Missouri, some P and K fertilizer was applied at all locations within the field for both SSM and CM treatments. Banding of immobile nutrients promotes high crop-use efficiency, but with that there was greater difficulty in finding P and K response differences between treatments. Differences between treatments were attributed to N. Yield patterns were similar to topsoil depth maps. Side-by-side yield transects of SSM and CM were compared. In a year with a wet early summer (1998), SSM resulted in yield depression from under application of N where topsoil depth was shallow. Dentrification was presumed to be a dominant N loss process. In the same year where topsoil was > 60 cm, N application with SSM produced higher (10%) yields than CM. In a dryer than average crop year (1997), yield on shallow topsoil areas was depressed with CM, where N rate was approximately 34 kg/ha greater than with SSM.. We attributed this difference to greater early season growth with more N applied with CM, depleting stored soil water and causing more water stress during pollination. Environmentally, no clear difference existed between the two management systems for post-harvest rootzone soil nitrate. Without knowledge of within season precipitation, predicting crop N needs using EC as a measure of topsoil thickness will be difficult.
PUBLICATIONS: 1995/09 TO 1999/02
1. Fraisse, C.W., K.A. Sudduth, N.R. Kitchen, and J.J. Fridgen. 1999. Use of unsupervised clustering algorithms for delineating within-field management zones. ASAE Paper 993043, ASAE, St. Joseph, MI.
2. Kitchen, N.R., K.A. Sudduth, J.G. Davis, C.W. Fraisse, S.T. Drummond. 1999. Precision Nitrogen Strategies for Midwest Claypan Soils. In Proc. Third National Workshop on Constructed Wetlands/BMPs for Nutrient Reduction and Coastal Water Protection. New Orleans, LA,9-12 June 1999.
Item No. 8 of 9ACCESSION NO: 0183251 SUBFILE: CRIS
INVESTIGATOR: Scharf, P. C.; Blackmer, A. M.; Kitchen, N. R.
UNIVERSITY OF MISSOURI
COLUMBIA, MISSOURI 65211
INNOVATIVE N MANAGEMENT SYSTEMS FOR CORN: SOURCE REDUCTION TO THE GULF OF MEXICO
OBJECTIVES: Test four innovative N management systems for corn developed by our research groups, comparing N management based on these systems to currently used N management systems. Evaluate system performance based on (1) reducing over-application of N fertilizer and (2) economics. Improve performance and ease of use of systems.
APPROACH: We will be testing these systems in replicated field-length strips, so that a variety of soil properties and landscape positions will be represented in each test location. We will have six experimental locations spread across two states to sample a broad range of climate and soil conditions. End-of-season corn stalk nitrate samples will be used to determine whether N was over- or under-applied at multiple locations in each strip. Yield relative to high-N strips will also be used to confirm under-application of N. Evaluation of where each system worked and where it didn't will allow us to refine these systems.
NON-TECHNICAL SUMMARY: Each summer a large low-oxygen zone forms on the Louisiana coastal shelf in the Gulf of Mexico, driving away fish and killing bottom-dwelling animals. The formation of this zone is fueled by nitrogen from the Mississippi River, which has increased dramatically since 1950, mainly from agricultural sources. Nitrogen fertilizer is often over-applied to crops to make sure that they have enough. Few tools have been available to farmers to match nitrogen fertilizer rates to actual crop needs. We will be conducting field-scale tests of four promising N recommendation tools that we have developed to see if they can maintain profitability while reducing over-application of nitrogen to corn.
PROGRESS: 2001/01 TO 2001/12
Five field-scale experiments were conducted in 2001 to investigate variability in nitrogen (N) fertilizer need of corn across landscapes and to evaluate new technologies for predicting N fertilizer need. Our goal is to develop N fertilizer recommendation systems that will meet corn needs but not leave extra unused N in the soil that can be lost to ground and surface waters. Fertilizer N moving through soil to surface waters via springs, seeps, and artificial drainage has been implicated in coastal eutrophication, including the annual hypoxic zone in the Gulf of Mexico. Experiments were located in producer corn fields in west-central Iowa (2), west-central Missouri, central Missouri, and southeast Missouri. Soils and production practices were typical for the region. Analyses that have been completed to date on results from these five experiments and on five similar experiments conducted in 2000 reveal the following major conclusions: 1) We observed high spatial variability in the amount of nitrogen fertilizer needed to maximize corn yields, particularly in the Missouri experiments. This suggests that spatially variable N fertilizer applications could have both economic and environmental benefits. 2) All experimental fields included large areas that needed less N fertilizer than normally applied by cooperating producers or recommended by our universities. Most fields also included large areas that needed as much as, or more than, rates that are currently recommended or used. 3) Areas of fields that had the highest yields were not the areas that needed the most N fertilizer. Sometimes the lowest-yielding areas were the ones that needed the least fertilizer, but in general there was very little connection between yield level and the amount of fertilizer needed. 4) Weather affected the amount of N fertilizer needed. In general, fields experiencing wet conditions needed more fertilizer, those experiencing dry conditions needed less. 5) Preliminary analysis shows some successes but some difficulties to overcome in predicting which parts of fields need more N fertilizer and which need less.
IMPACT: 2001/01 TO 2001/12
Our results suggest that spatially variable management of N fertilizer could contribute to reducing nitrogen losses from agricultural fields, and to improving water quality. Before this potential can be realized, more reliable ways must be developed to identify which areas of a field need more fertilizer and which need less.
PUBLICATIONS: 2001/01 TO 2001/12
1. Scharf, Peter C., John P. Schmidt, Newell R. Kitchen, Kenneth A. Sudduth, S. Young Hong, John A. Lory, and J. Glenn Davis. 2002. Remote Sensing for N Management. J. Soil Water Cons. (in press)
2. Scharf, P.C., N.R. Kitchen, J.G. Davis, K.A. Sudduth, and J.A. Lory. 2001. A success story: Sidedress N recommendations for corn based on an aerial photograph. Abstract in: Proceedings of the Third International Conference on Geospatial Information in Agriculture and Forestry.
3. Scharf, P.C., N.R. Kitchen, J.G. Davis, K.A. Sudduth, and J.A. Lory. 2001. Developing systems for variable-rate N recommendations for corn. Agronomy Abstracts, CD only, American Society of Agronomy, Madison, WI.
4. Zhang, J., A.M. Blackmer, and J.W. Ellsworth. 2001. Comparisons of chlorophyll meters and remote sensing for assessing nitrogen sufficiency of corn. Agronomy Abstracts, CD only, American Society of Agronomy, Madison, WI.
5. Ellsworth, J.W. and A.M. Blackmer. 2001. Remote sensing of corn and soybean fields to define nitrogen management units. Agronomy Abstracts, CD only, American Society of Agronomy, Madison, WI.
Name: Scharf, P. C.
Item No. 9 of 9ACCESSION NO: 0190470 SUBFILE: CRIS
INVESTIGATOR: Porterfield, D. M.
UNIVERSITY OF MISSOURI
ROLLA, MISSOURI 65401
CHARACTERIZATION OF METABOLIC AND IONIC FLUX PATTERNS FROM THE ROOTS OF RICE AND MAIZE IN RESPONSE TO HYPOXIA AND ANOXIA
OBJECTIVES: This research will focus on: 1) characterizing the basic relationship between metabolism, mineral nutrient ion transport and development in maize roots; 2) identify how these activities are maintained in response to low oxygen stress (hypoxia and anoxia) and the metabolic limitations associated with hypoxia/anoxia in the soil environment; 3) determine the exact physiological role of the fermentative enzyme, alcohol dehydrogenase, in the maintenance of the normoxic physiology and subsequent tolerance of maize roots to hypoxic/anoxic stress conditions.
APPROACH: The objectives listed above will be accomplished using an integrated biophysical/biochemical/physiological approach. Biophysical measurements will be accomplished through direct mapping of specific fluxes of ions and metabolites using the non-invasive, self-referencing microelectrode (SRM) technique. Using the SRM techniques it will be possible to map and characterize patterns of metabolic oxygen consumption and specific ion fluxes in relation to morphology, anatomy, and patterns of development of roots grown under normoxic or hypoxic/anoxic conditions. Biochemical measurements will be employed to quantify ADH activity and expression in the root tip in reponse to oxygen limitations. Localization patterns of ADH activity will be visualized using a cytochemical staining procedure and compared to the measured patterns of oxygen and ion fluxes under ambient oxygen conditions. The physiological importance of ADH activity in the tolerance of the maize roots to hypoxic/anoxic stress will be determined through the use of ADH null mutants and experiments that employ biophysical and biochemical measurements to compare these mutants to wild type roots.
NON-TECHNICAL SUMMARY: For crop plants one of the most common, but least understood forms of environmental stress is oxygen limitation in the roots system. This is commonly caused by waterlogging, which occurs when the soil atmosphere is displaced by water as a result of heavy rain, flooding or, as is now very common, over-irrigation. The direct and most immediate consequences of low oxygen conditions in the soil are inhibition of normal activities of the root and the resulting disruption of mineral nutrient uptake from the soil. The disruption of mineral nutrient uptake by the roots is a serious consideration for crop productivity as it known to lead to mineral nutrient deficits in the leaves and other aerial plant tissues that do lower overall yields. The objective of this research will be to better understand the relationship between oxygen availability and mineral nutrient uptake in corn roots. To determine how the corn roots respond and adapt to changes in the availability of oxygen in the soil, and to what level the adaptive response allows the root tip to reestablish normal mineral nutrient uptake and transport. By better understanding this problem and the adaptive response of roots to soil flooding stress we be able to develop strategies to better manage the impact of this on crop productivity. This could be accomplished by improved agricultural practices and modified fertilizer application strategies, as well as development of stress resistant varieties of corn through traditional breeding and genetic engineering.
Name: PORTERFIELD, D. M.