|CAMPBELL, ELEANOR - Colorado State University|
|PAUSTIAN, KEITH - Colorado State University|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/5/2012
Publication Date: 10/5/2012
Citation: Campbell, E.E., Johnson, J.M., Jin, V.L., Varvel, G.E., Adler, P.R., Paustian, K. 2012. Using DAYCENT to model the soil impacts of harvesting corn stover for bioenergy. In: Proceedings of the Sun Grant National Conference. Science for Biomass Feedstock Production and Utilization, October 2-5, 2012, New Orleans, LA. Available: www.sungrant.tennessee.edu/NatConference.
Interpretive Summary: The leaves, stalk and cobs that remain after corn grain is harvested is called stover. 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. Experimental greenhouse gas emission data, crop yield, and soil data were collected across the county. Carbon dioxide, nitrous oxide and methane are all considered greenhouse gases that may have undesirable climate effects. Soil organic matter gives soil a dark, rich color and is related to many desirable soil properties. It is important that harvesting corn stover does not decrease soil organic matter or increase greenhouse gas emission. Experimental data provided information at a specific site. Models like DAYCENT project how harvesting stover may impact soil organic matter or greenhouse gas emission. DAYCENT model did a good job of simulating changes in soil organic matter and crop yield compared to experimental data. DAYCENT performed poorly simulating nitrous oxide flux. This information will be used improve process models. The results of this work will help identify management that avoids undesirable impacts of harvesting corn stover for bioenergy feedstock. This information will benefit modelers by providing a unique opportunity to improve process models. It also provides guidance to the bioenergy industry, producers and the general public including policy makers of the benefits and risks associated with plant-based energy and leads to informed decisions.
Technical Abstract: Minimizing GHG emissions and avoiding soil C depletion associated with feedstock production is a key concern with the development of corn stover for biofuel, in order to prevent reductions in soil fertility and negative climate impacts from residue removal. While experimental data are valuable to understand site-specific corn stover removal impacts on soil C and GHG flux, models are a useful way to project how corn stover removal may impact the land on greater temporal and spatial scales. We used grain yield, soil C, and N2O flux data collected from multiple Corn Stover Removal Team experimental sites to test DAYCENT performance modeling the impacts of corn stover removal. We aggregated measured data across residue removal treatments and compared measured trends to DAYCENT modeled results. DAYCENT performed very well simulating SOC change and reasonably well simulating grain yields. In this analysis, residue removal did not significantly affect soil C or yields. DAYCENT performed poorly simulating N2O flux, and is an area for further model parameterization to understand GHG flux impacts with residue removal.