Does no-tillage mitigate stover removal in irrigated continuous corn? A multi-location assessment

Authors: Stewart, Catherine; Roosendaal, Damaris; Sindelar, Aaron; Jin, Virginia; Schmer, Marty

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2019
Publication Date: 2/22/2019
Publication URL: https://handle.nal.usda.gov/10113/6612026
Citation: Stewart, C.E., Roosendaal, D.L., Sindelar, A.J., Jin, V.L., Schmer, M.R. 2019. Does no-tillage mitigate stover removal in irrigated continuous corn? A multi-location assessment. Soil Science Society of America Journal. 83(3):733-742. https://doi.org/10.2136/sssaj2018.09.0352.
DOI: https://doi.org/10.2136/sssaj2018.09.0352

Interpretive Summary: No-tillage (NT) may reduce the negative effects on soil properties from corn (Zea mays L.) stover harvest. However, few long-term continuous corn irrigated production studies have quantified these effects. In this study, we evaluated three long-term sites in Nebraska and Colorado across a range of precipitation and soil organic C (SOC) stocks. We measured SOC, '13C of SOC, soil microbial biomass (SMB) and composition (PLFA), water stable aggregation, and other soil indicators including P, K, and EC. Overall, residue removal decreased SOC stocks by 6% and soil aggregation by 10% in the 0-30 cm depth, with the majority of the change observed in the surface (0 to 7.5 cm). Residue harvest did not change SMB or change soil microbial community structure, suggesting that high plant productivity buffered these communities from residue-harvest impacts under NT, despite SOC loss from increased microbial decomposition of soil C. These sites had lower SOC stocks and aggregation compared to residue retained treatments, suggesting that conservation tillage alone is inadequate in maintaining erosion protection and soil function.

Technical Abstract: No-tillage (NT) may ameliorate the negative effects on soil properties from corn (Zea mays L.) stover harvest. However, few long-term continuous corn irrigated production systems have quantified these effects. In this study, we evaluated three long-term sites in Nebraska and Colorado across a range of precipitation and soil organic C (SOC) stocks. We measured SOC, '13C of SOC, soil microbial biomass (SMB) and composition (PLFA), water stable aggregation, and other soil indicators including P, K, and EC. Sites ranged in SOC content from 15.4, 19.1, to 21.0 Mg C ha-1 for Colorado, central Nebraska, and eastern Nebraska, respectively and were well correlated with aboveground residue returned to the soil (r2 = 0.66). Overall, residue removal decreased SOC stocks by 6% and soil aggregation by 10% in the 0-30 cm depth, with the majority of the change observed in the surface (0 to 7.5 cm). The '13C signature of SOC indicated less new C storage under residue removal. Residue harvest did not decrease SMB or change soil microbial community structure, suggesting that high plant productivity buffered these communities from residue-harvest impacts under NT, despite SOC loss from increased microbial decomposition of the soil C pool. These sites had lower SOC stocks and aggregation compared to residue retained treatments, suggesting that conservation tillage alone is inadequate in maintaining erosion protection and soil function.