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Title: Can APEX Represent In-Field Spatial Variability and Simulate Its Effects On Crop Yields?

item Baffaut, Claire
item Sadler, Edward
item MUGDAL, ASHISH - Monsanto Corporation
item STEVEN, ANDERSON - University Of Missouri
item Sudduth, Kenneth - Ken
item Kitchen, Newell

Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2010
Publication Date: 8/7/2011
Citation: Baffaut, C., Sadler, E.J., Mugdal, A., Steven, A.H., Sudduth, K.A., Kitchen, N.R. 2011. Can APEX Represent In-Field Spatial Variability and Simulate Its Effects On Crop Yields? [abstract]. ASABE Annual International Meeting, August 8-10, 2012, Louisville, Kentucky. 1111424.

Interpretive Summary:

Technical Abstract: Precision agriculture, from variable rate nitrogen application to precision irrigation, promises improved management of resources by considering the spatial variability of topography and soil properties. Hydrologic models need to simulate the effects of this variability if they are to inform about the benefits of precision agriculture. In this study, we assessed the performance of the APEX model in simulating temporal and spatial variations of crop yields on claypan soils. Twenty-seven 200-m long plots divided into 5 landscape positions, and one 35-ha field divided into 35 subareas, were individually simulated with APEX using subarea-specific soil properties and topography, year- and plot-specific management parameters, and on-site weather. The models were calibrated based on measured crop yields in each subarea and environmental variables (runoff and dissolved pollutants) at the outlet of the field and selected plots during selected years. Preliminary results indicate good temporal simulation of crop yields in the field (r2 = 0.74). Corn exhibited the most spatial yield variability, which was reproduced during dry years. During wet years, average yields were well simulated but spatial distributions were not. These results will improve understanding of and confidence in APEX; scientists, action agencies, and conservation interests will benefit from the research.