No-till marginally mitigates the impact of harvesting stover on soil microbial parameters

Authors: Ramirez, Salvador; Jin, Virginia; GUNDERSON, LANCE - University Of Nebraska; Schmer, Marty; HANFORD, KATHRYN - University Of Nebraska; JESKE, ELIZABETH - University Of Nebraska; DRIJBER, RHAE - University Of Nebraska

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2023
Publication Date: 9/21/2023
Citation: Ramirez II, S., Jin, V.L., Gunderson, L., Schmer, M.R., Hanford, K., Jeske, E., Drijber, R. 2023. No-till marginally mitigates the impact of harvesting stover on soil microbial parameters. Soil Science Society of America Journal. 87(6):348-1364. https://doi.org/10.1002/saj2.20592.
DOI: https://doi.org/10.1002/saj2.20592

Interpretive Summary: No-till soil management is often recommended as a companion practice to help lessen the negative impacts of removing crop residues on soil erosion, but it is not clear whether no-till is as effective on ameliorating soil biological properties. We measured the effect of mechanically removing corn stover at three different rates(none, moderate, high) under no-till or disk tillage in surface soils at a long-term irrigated continuous corn system in eastern Nebraska. We found that there were some mitigating effects of no-till on soil biological properties. Overall, harvesting stover decreased soil microbial biomass regardless of tillage practice. Harvesting stover also decreased microbial nutrient cycling, and these microbial activities were even further reduced under conventional tillage. In this 13-year study, we found that pairing no-till management with moderate stover removal rates was the most effective management practice combination that helped reduce impacts on soil microbial communities and functioning.

Technical Abstract: Harvesting corn (Zea mays L.) stover can negatively impact soil chemical and physical properties, but less is known regarding effects on soil biology. Our objectives were to evaluate the impact of stover removal on soil microbial biomass and extracellular enzyme activities in a 13 yr, irrigated, continuous corn study located in the western U.S. Corn Belt. Soil microbial biomass and the potential activity of eight extracellular enzymes were measured in surface soil (0-20 cm) three times during the growing seasons of 2014 and 2015 under conventional disk tillage (CT) and no-till (NT) with three residue removal levels (none, moderate, and high). Soil microbial biomass decreased with residue removal (P<0.05) in both years. Canonical discriminant analysis (CDA) of fatty acid methyl esters (FAMEs) separated the influence of tillage at all three corn growth stages and the influence of residue removal at later maize growth stages. These findings were consistent with disturbance- and input-mediated modifications of the soil environment and microbial communities therein. Activities of all eight extracellular enzymes decreased with increasing residue removal rate and with tillage. No-till, however, partially ameliorated the negative impact of stover removal on soil enzymatic activities critical to nutrient cycling, suggesting that pairing NT with stover removal may be a more sustainable practice in the long-term.