Title: Apex Simulations of Productivity for 9 Cropping Systems over 19 Years in 3 Claypan Landscape Positions Authors
Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: January 19, 2010
Publication Date: July 17, 2010
Citation: Sadler, E.J., Baffaut, C., Kitchen, N.R., Sudduth, K.A., Mudgal, A. 2010. APEX Simulations of Productivity for 9 Cropping Systems over 19 Years in 3 Claypan Landscape Positions [abstract]. Soil and Water Conservation Society Annual Conference, July 18-21, 2010, St. Louis, Missouri. Available: http://www.swcs.org/documents/filelibrary/10ac/2010_Oral_Presentation_Abstracts_566DF5164F928.pdf. Technical Abstract: Prior research has shown that conventional corn-soybean cropping systems are economically riskier in the claypan MLRA, caused by variable rain and limited water holding capacity above the low-permeability claypan. These observations prompted research into alternative cropping systems that offer more stable yields and thus profitablility. A replicated experiment with 10 treatments was established for this purpose in 1991. In each of three replications, 0.85-acre (0.34-ha) plots were subjected to all phases of mulch-till corn-soybean and no-till corn-soybean for the entire period of record. Other treatments were modified during the period of record, leaving 5 years of mulch-till corn-soybean-wheat-cover crop, 14 years of no-till corn-soybean-wheat-cover crop, 3 years of ridge-till corn-soybean, 9 years of no-till corn-soybean with variable-rate fertilization , 7 years of no-till corn-soybean-switchgrass, 19 years of cool-season grass (to CRP standards), and 9 years of both warm-season grass/legume CRP and warm-season grass hay. The treatments involving CRP were split (making 20x620’ [6x189 m] plots within one original 60x620’ [18x189 m] plot). After calibration and validation of the APEX model on 12 plots, all plot-years were simulated using plot-specific soil parameters, year- and cropping-system-specific management parameters, and on-site weather. Landscape position (summit, sideslope, and footslope) and whole-plot yields were compared with measured values. From these results, confidence in the APEX model in the claypan context will be increased, and productivity of these cropping systems will be documented. Scientists, action agencies, and conservation interests will benefit from the research.