Search USDA's Current Research Information System (CRIS) Database
Item No. 1 of 2ACCESSION NO: 0167348 SUBFILE: CRIS
INVESTIGATOR: Francis, C. A.
CENTER FOR SUSTAINABLE AGRIC SYSTEMS
UNIVERSITY OF NEBRASKA
LINCOLN, NEBRASKA 68583
BIOLOGICAL AND ECONOMIC CONSEQUENCE OF FLEXIBLE CROP ROTATIONS
OBJECTIVES: PROJ. #9403967. Measurement of previous crop effects; evaluation of economics and risk; information and technology transfer.
APPROACH: Evaluation of crop yields will derive from past and ongoing rotation experiments, design and implementation of specific component research, and acquisition of data from farmers to validate results from current field research; these will allow design of biologically optimum and productive rotation sequences. Comparison of fixed versus flexible rotations requires valid yield and production cost data, and from this we will determine the economically optimum sequences considering labor, machinery, and cost/return budgets. Technology transfer will include extension meetings with farmers as well as estimation of the value of information in making decisions on cropping patterns under conditions of uncertainty; included will be an education program for classroom and extension audiences to describe both the biological and economic impacts of crop rotations.
NON-TECHNICAL SUMMARY: Crop rotations generally follow fixed patterns, while biological and economic conditions are always changing on the farm. Flexible choice of crops and varieties can take advantage of new information on soil and pest conditions, changes in the marketplace, newly available crop cultivars, and better understanding of the efficiency of water and nutrient use. Long-term rotation experiments are being analyzed to assess the value of this approach to crop rotation.
PROGRESS: 1994/09 TO 1999/09
Flexible crop rotations based on soil moisture and fertility status as well as commodity prices provide an alternative to long-term, fixed sequence rotations. Research on long-term crop rotations shows clear evidence of higher production, lower input costs, and greater stability in a four-year rotation compared to continuous corn. Two-year rotations of corn-soybean and sorghum-soybean are similar to four-year rotations, but have higher returns with today's commodity prices. Rotations of sorghum with soybean enhanced yields of both crops, and rainfall influenced uptake and use of N fertilizer. Both lower fertilizer costs and success under limited rainfall conditions make sorghum a good crop choice in years of below average rainfall. When rainfall data are summarized in a specific precipitation index (SPI), using this data before planting time to make crop choices can enhance the array of information available to the farmer. Both weather and management decisions affect variability of crop yields in these rotations. Higher profits are found in rotations of sorghum with soybean in dry years due to higher sorghum yields and lower fertilizer costs. In general, it is helpful to reduce inputs in years when unfavorable weather can be predicted.
IMPACT: 1994/09 TO 1999/09
Research on flexible crop rotations shows that data on rainfall, previous crop yields, and soil fertility status can be used to make decisions on the coming year's crop and rotation. Of these factors, rainfall and soil moisture status are by far the most important, and analysis of long-term data show that sorghum is more profitable than corn when soil moisture is below average before planting time.
PUBLICATIONS: 1994/09 TO 1999/09
1. Lesoing, G.W., and Francis, C.A. 1999. Strip intercropping of corn-soybean in irrigated and rainfed environments. J. Prod. Agric. 12:127-128, 187-192.
2. Olson, R.K. 1998. Procedures for evaluating alternative farming systems: a case study for eastern Nebraska. Ext. Educ. Materials for Sustain. Agric. Vol. 8, Ctr. Sust. Agric. Sys., Univ. Nebraska, Lincoln. 292 p.
3. Yamoah, C.F., G.E. Varvel, C.A. Francis, and W.J. Waltman. 1998. Weather and management impact on crop yield variability in rotations. J. Prod. Agric. 11:161-162,219-225.
4. Yamoah, C.F., M.D. Clegg, and C.A. Francis. 1998. Rotation effect on sorghum response to nitrogen fertilizer under different rainfall and temperature environments. Agric., Ecosystems and Environ. 68:233-243.
Name: Francis, C. A.
Item No. 2 of 2ACCESSION NO: 0193096 SUBFILE: CRIS
INVESTIGATOR: Dosskey, M. G.; Hoagland, K. D.; Brandle, J. R.
NATIONAL AGROFORESTRY CENTER
NORTH 38TH & EAST CAMPUS LOOP
LINCOLN, NEBRASKA 68583-0822
CHANGE IN FILTER STRIP PERFORMANCE OVER TIME
OBJECTIVES: Determine if, and by how much, the effectiveness of filter strips changes over time since establishment. Determine if temporal change in effectiveness depends on vegetative composition. Partition change among fundamental processes of infiltration, deposition, and dilution.
APPROACH: The same filter strip field plots and experimental protocols used by Schmitt et al. (J. Environ. Qual. 1999, 28:1479-1489) in years 1, 2 and 3 after filter strip establishment will be repeated in years 9 and 10. In general, the methods call for applying identically-prepared solutions that simulate field runoff containing sediment, N and P fertilizer, and bromide tracer to the upper end of filter strip plots, and then measure their load and concentration in outflow. Water and pollutant outflow in years 9 and 10 will be compared to existing data from years 1, 2, and 3 by repeated measures ANOVA. Interaction between vegetation type and time since establishment will be examined by comparing results for two filter strip vegetation types, grasses only and grass plus trees. Individual filter processes for each year and vegetative treatment will be estimated and contrasted using the following relationships: Deposition = % reduction of sediment mass; Dilution = % reduction of bromide concentration; Infiltration = % reduction of bromide mass.
NON-TECHNICAL SUMMARY: Vegetation filter strips are installed at crop field margins for the purpose of removing pollutants from field runoff before they enter streams. This project will determine how much their effectiveness changes over the long term, if that change depends on the kind of plants that are grown in the filter strip, and which soil and vegetation processes account for such change. The information produced will improve our capabilities to predict the level of benefits to expect from filter strip establishment and the potential for success of USDA incentive programs. This information will also improve planning and design of efficient filter strips, in particular improved management schemes that will maintain a high level of benefit to water quality in agricultural watersheds.
Name: DOSSKEY, M. G.