Author
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Kitchen, Newell |
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Sudduth, Kenneth - Ken |
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Submitted to: National Conservation Tillage Cotton and Rice Conference Proceedings
Publication Type: Proceedings Publication Acceptance Date: 1/24/2002 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Many producers who map yield want to know how soil and landscape information can be used to help explain yield variability and provide insight into improving production. This study investigated the relationship of profile soil electrical conductivity (EC)and terrain factors with corn and soybean grain yield for six contrasting soil-crop systems in the Midwest (IA, IL, MI, MO, SD, and WI). Yield data were collected with combine yield monitoring systems during the 1997-2000 growing seasons. Soil EC was obtained using a rolling coulter device. Elevation, obtained by RTK GPS, was used to determine slope, curvature, and aspect. Three analysis procedures were employed to investigate the relationship of these variables to yield: correlation, multivariate stepwise regression, and boundary line analysis. Correlation results, while often statistically significant, were generally not very useful in explaining yield variation. Using regression analysis soil EC alone explained yield variability better than the other landscape variables, but elevation and slope were often significant in the multiple variable analysis. Combining soil EC and topography measures together usually improved model R**2 values by 50 to 80%. Boundary lines generally showed yield decreasing with increasing EC for fields in MO and SD, where water stress was more likely due to less precipitation. Regardless of the analytical procedure used, soil EC was the most important parameter for explaining yield variability and, as such, is an effective measurement for delineating productivity management zones within fields. |
