Submitted to: Soil and Water Conservation Society
Publication Type: Abstract only
Publication Acceptance Date: 3/15/2010
Publication Date: 7/18/2010
Citation: Landers, G.W., Thompson, A., Kitchen, N.R. 2010. Managing Claypan Soils: Annual Grain Crops vs. Perennial Switchgrass [abstract]. 65th Soil and Water Conservation Society's International Conference Program and Abstract Book. Paper No. 57. Interpretive Summary:
Technical Abstract: Topsoil depth and landscape position are important factors in the claypan region of Missouri for agricultural productivity and soil-water conservation. Shallow topsoil reduces grain productivity and causes yield inconsistencies, while traditional grain cropping increases soil erosion and nonpoint source pollution. Ensuring soil productivity and long-term sustainability may require a shift to more soil-protective management practices. Claypan soils show potential for conversion from grain to grass production in support of biomass energy markets and conservation programs. This study examines the economic potential of transitioning from grain to perennial switchgrass production and how topsoil variability by landscape position affects productivity on claypan soils. Two research sites with varying topsoil depths and underlying claypan layer were used in the study. Long-term plots were established in 2003 with a unique 3-year rotation: corn interseeded with switchgrass followed by switchgrass and then soybeans on three landscape positions (summit, side-slope, and back-slope). Additional plots were established in 2009 with switchgrass and corn-soybean rotations on four topsoil thickness treatments (<2, 2-7, 7-15, and >15 cm). Measurements included grain and biomass yield, and switchgrass plant density by topsoil thickness and landscape position. While corn grain production has been shown to be highly correlated with topsoil depth, we hypothesize a weaker correlation between switchgrass productivity and topsoil thickness. Further modeling of switchgrass and annual grain crops using the ALMANAC model and a partial budget analysis are expected to highlight the stability of a switchgrass system. Project results will aid farmers/landowners with future decisions concerning best management of claypan soils.