Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 22, 2004
Publication Date: September 22, 2004
Citation: Kitchen, N.R., Sudduth, K.A., Myers, D.B., Massey, R.E., Drummond, S.T. 2004. Spatially-variable crop and soil monitoring for enhanced production and conservation [abstract]. Monitoring Science and Technology Symposium. September 20, 2004. Denver, CO. Technical Abstract: Some producers have obtained spatial measurements of crop grain yield and soil-test nutrients for over a decade. Those doing this type of monitoring are interested in knowing how long-term spatial datasets can be analyzed to develop more profitable management plans. The objective of this paper is to show how a decade-long database of mapped yield and soil information from a Missouri field has been used to develop a precision agriculture plan. Yield and soil nutrient variability have been monitored on a 36-ha claypan soil field in central Missouri since 1992. Ten years of yield maps were transformed into profit maps using actual input expenses, estimated land and equipment costs, and local grain prices. During the spring of odd years soil samples were taken on a 30-m grid and analyzed for nutrients using standard laboratory methods. Change in soil test nutrients over time were related to removal of nutrients in the harvested grain. This relationship was used to calculate and map a site-specific nutrient buffering index. For the profitability analysis, soybean (Glycine max L.) was generally more profitable and more spatially-stable than corn (Zea mays L.). Profitability analysis identified several areas within the field that rarely produced a profit. Areas most often losing money were sideslopes where the topsoil was eroded. Profitability analysis of yield data provided a quantitative feedback of the economic loss from trying to produce a crop on these areas. The decade-long profitability analysis was used as a blueprint for identifying sensitive areas within the field that warranted specific management practices (i.e., site-specific management). Soil and water quality monitoring on this same field has indicated that future management should also include practices that reduce sediment and herbicide loss. A specific precision agriculture system has been developed for this field to simultaneously address site-specific production and conservation issues. For this system, the site-specific nutrient buffering index was used to determine site-specific phosphorous and potassium fertilizer-rate recommendations. This new management system will be implemented and monitored, and results compared to past performance of conventional, whole-field management.