|LAMB, JOHN - University Of Minnesota
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/5/2012
Publication Date: 10/5/2012
Citation: Johnson, J.M., Varvel, G.E., Stott, D.E., Osborne, S.L., Novak, J.M., Karlen, D.L., Lamb, J., Baker, J.M. 2012. Corn stover management effects on soil organic carbon contents from several U.S. locations. In: Proceedings of the Sun Grant National Conference. Science for Biomass Feedstock Production and Utilization, October 2-5, 2012, New Orleans, Louisiana. Available: http://sungrant.tennessee.edu/NatConference/ConferenceProceedings/.
Interpretive Summary: The leaves, stalk and cobs that remain after corn grain is harvested. Corn stover is expected to be used as major non-food bioenergy feedstock. Corn stover can be used to produce ethanol, or as a substitute for coal or other fossil fuels. However, enough stover still needs to be returned for soil cover and to build new soil organic matter. Soil organic matter gives soil a dark, rich color and is related to many desirable soil properties. This study used new and previously published data to understand how harvesting stover may alter soil organic matter. After accounting for tillage, sand content, elevation, and mean annual precipitation were important for predicting how stover harvest may change soil organic matter content. This information provides guidance to the bioenergy industry, producers and the general public including policy makers of the benefits and risks associated with plant-based energy. Overharvesting the stover could damage the soil, compromising the ability of those soils to provide food, feed, fiber and fuel for the world.
Technical Abstract: Corn stover is anticipated to be a major bioenergy feedstock, which is dependent upon high quality soil. Thus, the soil resource provides the foundation for building a sustainable biofuel economy. As a bioenergy foundation, this resource must be safeguarded from overzealous residue harvest, which can exacerbate erosion and a loss of soil organic carbon (SOC). Furthermore, greater amounts of residue return may be needed to maintain SOC than control erosion. Replicated plots established on productive soils were included in a multi-location (six states, 16 sites) and a multi-year study to determine the amount of corn stover needed to maintain SOC. A related objective assessed how management, climate and initial soil parameters influence stover response to stover harvest. These sites represented a range of soil types, climatic conditions, and study duration. All sites had at least three levels of stover harvest: grain only (control), maximum possible residue removal and an intermediate rate. Regression analyses were used at each site to estimate the relationship between the actual amount of stover returned and the change in SOC. These sites provided SOC and corn stover data to facilitate calculation of a minimum biomass that needs to remain on the field to avoid a SOC loss. This synthesis will help refine stover harvest recommendations that safeguard the soil resource and future productivity.