Submitted to: Soil and Water Conservation Society
Publication Type: Abstract only
Publication Acceptance Date: 8/18/2010
Publication Date: 9/28/2011
Citation: Landers, G.W., Thompson, A., Kitchen, N.R., Massey, R.E., Brune, D.E. 2011. Biofuel feedstock from claypan soils for annual grain and perennial switchgrass [abstract]. Soil and Water Conservation Society Workshop, September 28-30, 2010, Atlanta, Georgia. p. 17. Interpretive Summary:
Technical Abstract: Crop production on the claypan region soils of the U.S. Midwest is an important contributor for agricultural production. However, because of their tendency for grain yield fluctuations caused by water stress, claypan soils may have potential for conversion from grain to grass production in support of biomass energy markets and conservation programs. While corn grain production has been shown to be highly correlated with topsoil depth (a soil property highly variable within fields), we hypothesize a weaker correlation between switchgrass productivity and topsoil thickness. From this we also hypothesize that switchgrass will have a lower risk for production than corn on claypan soils. This study examines the economic potential of transitioning from grain crops to perennial switchgrass production on claypan soils. Baseline data from two sites with varying topsoil depths and underlying claypan layer were used to establish a partial budget analysis to evaluate the stability of a switchgrass system. Specifically, yield and price requirements were used to establish a switchgrass market for Missouri claypan soils. Comparisons include biomass production useful for bioenergy conversion as heating fuel and fluid energy conversion as cellulosic feedstock. Results show that with an average switchgrass yield of 6 ton/acre, the farmgate price would need to be $50/ton in order to compete with 110 bu/acre corn production on the same soils. Alternatively, projections based on cellulosic ethanol conversion and heating values (coal) suggest a required yield range between 12 and 28 tons per acre, respectively, in order to remain competitive with annual corn production (based on $4/bu). Data collected from research plots with four topsoil depth treatments (<5, 5-18, 18-38, and >38 cm) included grain and biomass yield, and switchgrass plant density (during establishment) by topsoil thickness and landscape position. Results indicate successful stand densities (20+ plants/m^2) are achievable across varying topsoil thicknesses; however, the effect of topsoil depth on biomass yield will not be evaluated until this fall. Modeling of annual grain crop production using the ALMANAC model accounted for 67% of the variability in measured yields across varying topsoil thicknesses. Switchgrass production will be evaluated with this same model.