Impact of High‐Lignin Fermentation Byproduct on Soils with Contrasting Organic Carbon Content

Abstract

Agricultural biomass is a potential renewable biofuel that may partially replace nonrenewable fossil fuels. Corn stover is rich in cellulose and hemicellulose, both of which can be converted to sugars and fermented to ethanol. This fermentation process results in a high‐lignin fermentation byproduct (HLFB) that could be converted to energy products or used as a soil amendment. We had two objectives: (i) to determine whether HLFB (0.1, 1.0, or 10 kg m−2) could improve soil properties in two soils with contrasting levels of soil organic carbon (SOC); and (ii) to assess the impact of HLFB on crop growth. These goals were addressed with separate experiments. In the soil experiment, two soils were amended with HLFB or ground corn (Zea mays L.) stover and then incubated in pots for 118 d. Flux of CO2 was monitored and soil properties were measured after incubation. In the plant experiment, corn and soybean [Glycine max (L.) Merr.] were grown in pots, without amendment or amended with 1.0 kg m−2 corn stover or 1.0 kg m−2 HLFB. The soil experiment indicated that the addition of 10 kg m−2 HLFB increased CO2 emission, humic acid concentration, and water‐stable aggregates, and decreased bulk density (Db). No adverse impacts on crop growth were measured when HLFB was applied at a rate of 1.0 kg m−2 Much of the HLFB may be used by the energy industry, but perhaps a percentage could be returned to the field to reduce the impact of corn stover removal on soil C.