Proceedings
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| Filter results11 paper(s) found. |
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1. Spatial Analysis of Yield-Limiting FactorsThe spatial relationship between crop yields and soil and site parameters was modeled using several methods. Yield maps estimated by projection pursuit regression and neural network analysis agreed well with measured yields. These methods also allowed generation of response curves for estimated yield as a function of each of the input parameters. These response curves were useful for investigating the relationship between yields and individual soil and site parameters. ... |
2. Spatial Prediction of Crop Productivity Using Electromagnetic InductionAn inexpensive and accurate method for measuring water-related, within-field soil productivity variation would greatly enhance site-specific crop management strategies. This paper reports on investigations to use an electromagnetic induction (EM) sensor to map claypan (Udollic Ochraqualfs) and alluvial (Typic and Aquic Udipsarnnlents, and Aeric Fluvaquents) soil conductivity variations and to evaluate the relationship of EM measurements to grain crop production. Grain yield measurement was obtained... |
3. An Evaluation of Methods for Determining Site-Specific Management ZonesNumerous procedures have been examined for identifymg management areas within fields. Traditional soil surveys give a general understanding of the effects soil mapping units have on crop productivity. In the USA. county soil surveys report the average grain yield of major crops by soil series. Slope position and landform are topographic features thal also have been used to explain water and crop productivity relationships (Mulla et al., 1992; Sudduth et al., 1997). Generally, footslope positions... |
4. Cover Crop Impacts on Corn and Soybean Nitrogen Accumulation and YieldThe need to retain soil N between economic crops has renewed interest in cover crops for the eastern cornbelt but their management remains a barrier to widespread adoption. We conducted a 3 site-yr study to determine effects of cover species (wheat or rye) and biomass management (burndown 40 d, 20 d, or 2 d preplant) on corn and soybean yields. Sites included a very poorly drained (wland wlo tile drainage) and a well drained silt loam. With adequate drainage, cover biomass 40 d preplant averaged... |
5. Nitrate Concentrations in Drainage Water from a Continuous Corn Production System- Impacts of Tile Spacing and Precipitation EventsCharacterization of agricultural drains as point sources for nitrates in surface waters has generated keen interest in regional grab-sample monitoring programs. Grab sample tile drain monitoring programs are being explored by numerous public and private organizations interested in encouraging BMPYs for nitrogen and/or implementation of TMDL policy. Our objective was to determine if nitrate concentrations in water collected from individual tile lines could be interpreted independent of information... |
6. How Does Your Garden Grow? Fertilizer- Friend or FoeGeo-spatial technologies are becoming common place in commercial agriculture and hands-on exercises using these concepts and technologies klfill many state K-12 education standards. The activity topics covered crop nutrients (nitrogen, phosphorus and potassium), global positioning systems (GPS), geographic information systems (GIs), types of agricultural field equipment, soil types and crop identification. Students developed and implemented plant growth experiments to test nutrient application hypotheses.... |
7. Nitrate Concentrations and Flux in Drainage Water- Impacts of Tile Spacing and Precipitation Events and Implications for TMDLSIn the humid region of the eastern cornbelt efforts to optimize productivity of poorly drained soils has led to increased spatial intensity of agricultural tile drains. This intensification in installation of drainage tile is often a primary management consideration when field cultivation is being minimized or eliminated entirely. The objective of this study was to quantify the effects of tile spacing on the concentration and flux of nitrate in tile effluent. Continuous corn was grown on a well-structured,... |
8. An Overview of On-Farm Nitrogen Rate ResearchBecause crop advisors, farmers, and some in the fertilizer industry questioned the University's N recommendations as being too low and raised concerns that the N calibration research had been done primarily in small plots on University Experiment Station land. numerous N calibration studies for corn after soybeans were conducted on farmers' fields in southern Minnesota and northeastern Iowa from 1989 through 2002 to validate present N recommendations. On-farm replicated trials were conducted by University... |
9. Fertilizer Industry Update- Price, Availability, HistoryThis talk will review world and local factors that have been affecting fertilizer demand, pricing, and supply. The speaker will review fertilizer trends and usage in the world markets as well as discuss trends in the U.S. fertilizer industry. Due to the proprietary nature of most of the information, a paper is not included in the proceedings. Select slides may be available upon request. however. ... |
10. What Do You Do When Your N-Rich Reference Fails?In recent years, canopy reflectance sensing has b een investigated for in-season assessment of crop N health and fertilization. Typically, the procedure followed co mpares the crop in an area known to be non-limiting in N (the N-rich area) to the crop in a target area, which may be inadequately fertilized. Measurements from the two areas are used to calculate a relative reflectance to represent the potential need for add itional N fertilizer. Establishing N rich areas or strips is often inconvenient... |
11. What are the Benefits of Canopy Sensing for Variable-Rate Nitrogen Corn Fertilization?Canopy reflectance sensing for assessing crop N health has been proposed as a technology on which to base top-dress variable-rate N applicat ion. The objective of this research in Missouri was to evaluate the economic a nd environmental benefit of activ e-light crop-canopy reflectance sensors for corn N rate decisions. A total of 16 field-scale experiments were conducted over four seasons (2004-2007) in three major soil areas. Mu ltiple blocks of randomized N rate response plots traversed the length... |