Submitted to: Geospatial Information in Agriculture and Forestry International Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 7, 2001
Publication Date: N/A
Technical Abstract: Crop yield is affected by many factors, primarily encompassed within soil, weather, and agronomic management practices. Crop modeling can be used to help understand how multiple factors interact to impact yield. The CROPGRO crop model system has been applied to various research areas and has proven to be very useful in simulating soybean growth and development. However, the model has not been thoroughly evaluated for some environments that hav unique characteristics. The objectives of this study were to evaluate the performance of the CROPGRO-Soybean model for simulating site-specific crop growth, soil water content, and grain yield on claypan soils. Data were obtained during dry and average-precipitation weather conditions from two fields over three years in central Missouri. Plant (e.g., yield, leaf area, root length density) and soil (e.g., topsoil thickness, moisture, texture) measurements were collected for calibrating and validating the model. Results indicated that CROPGRO-simulated soil water contents in th 15-90 cm soil profile agreed well with measured values. Simulated leaf area index and grain yield also agreed well with measured values during average precipitation years but were under estimated during extremely dry years. Within-season precipitation and claypan soil topsoil depth were shown to have the greatest influence on soybean yield. Although we hypothesized it to be otherwise, field measurements in 1997 showed that the claypan did not negatively affect soybean root penetration.