Location: Agroecosystems Management ResearchTitle: CO2 fluxes and C budgets affected by stover harvest in Iowa continuous corn systems
|Sauer, Thomas - Tom|
|ARCHONTOULIS, SOTIRIOS - Iowa State University|
|KARLEN, DOUGLASS - Retired ARS Employee|
|LAIRD, DAVID - Iowa State University|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/13/2020
Publication Date: 11/13/2020
Citation: O'Brien, P.L., Sauer, T.J., Archontoulis, S., Karlen, D.L., Laird, D.A. 2020. CO2 fluxes and C budgets affected by stover harvest in Iowa continuous corn systems [abstract]. ASA-CSSA-SSSA Annual Meeting. 128195.
Technical Abstract: Harvesting corn (Zea mays L.) stover for use as bioenergy feedstock may provide short-term economic benefits and perhaps improve grain yield in continuous corn systems. However, excessive stover removal may lead to long-term depletion of soil C stocks. We measured an important component of the soil C balance, CO2 fluxes, under three stover harvest treatments (none, moderate, and high) in three continuous corn systems: (1) no tillage and no biochar applications; (2) chisel plowing with biochar amendments; and (3) chisel plowing without biochar amendments. We sampled static chambers 14, 13, and 15 times in 2010, 2011, and 2012, respectively, and used these measurements to calibrate the Agricultural Production Systems sIMulator (APSIM) model to estimate cumulative CO2 fluxes. Although total CO2-C loss did not differ among the three systems, both moderate (approximately 30%) and high (approximately 60%) rates of stover removal reduced simulated CO2-C losses by nearly 10% and more than 22%, respectively. Despite these reductions in CO2 flux, the sum of CO2-C and stover C removal exceeded CO2-C losses in systems without stover removal by up to 1000 kg C ha-1 yr-1. This suggests that stover removal may result in soil C depletion for the soil and crop management practices used in this study, though depletion was not evident after three years. Application of biochar did increase soil C levels, suggesting it may be able to offset some C losses. Overall, these findings indicate that for sustainable, highly productive agroecosystems that include stover harvest, agronomic management practices must be optimized to minimize C losses and maintain soil quality.