Characterization of soil amended with the by-product of corn stover fermentation

Corn (Zea mays L.) stover is a potential biofuel; however, removing this stover from the land may increase the risk of erosion and reduce soil organic matter (SOM). Land application of corn stover fermentation by-product, which is about 70% lignin, may reduce the environmental risk from biofuel harvest by helping to stabilize soil structure. A column study, with soil collected from a toeslope (noneroded, Svea; fine loamy, mixed, superactive, frigid Pachic Hapludoll) and a shoulder slope (severely eroded, Langhei; fine loamy, mixed, superactive, frigid Typic Eutrudepts) was conducted to evaluate the effect of fermentation by-product on soil properties. Soil was either not amended (control) or amended with corn stover or by-product at 0.75, 3.0, and 6.1 g kg(-1). Soils were incubated for 123 d at ambient temperature in a laboratory, with an initial water-filled pore space (WFPS) of 0.6 m(3) m(-3) and drying cycles to 0.35 m(3) m(-3) WFPS. Compared with the control, amending soil with 6.1 g by-product kg(-1) increased CO2 flux by 68% and increased soluble C and microbial biomass C by about 20%. In the severely eroded soil, humic acid concentration (r(2) = 0.97,p = 0.009) and aggregate stability (r(2) = 0.98, p = 0.005) increased linearly with increased by-product concentration. Water-holding capacity, bulk density, and aggregate distribution were not changed by soil amendments. Careful management of stover removal (avoiding eroded or erosion prone areas) and selective placement and rates of the by-product will contribute to a sustainable use of corn stover for ethanol production.