Soil health dynamics under different cover crop grazing periods in the Southeastern U.S.

Authors: REITER, WADE - Auburn University; GAMBLE, AUDREY - Auburn University; FENG, YUCHENG - Auburn University; CROWELL, HAYLEY - Auburn University; Balkcom, Kipling

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2023
Publication Date: 11/2/2023
Citation: Reiter, W., Gamble, A.V., Feng, Y., Crowell, H., Balkcom, K.S. 2023. Soil health dynamics under different cover crop grazing periods in the Southeastern U.S. [ABSTRACT]. 2023 ASA-CSSA-SSSA International Meeting Oct. 29 - Nov. 1, 2023.

Interpretive Summary:

Technical Abstract: Introducing integrated crop-livestock systems into row crop production may provide incentives for producers to plant cover crops and promote soil health benefits on degraded soils of the southeastern United States, but the effects of these practices on crop yields and soil health in southeastern Ultisols are not well established. A four-year study was established at the Wiregrass Research and Extension Center in Headland, Alabama to test the effects of different grazing regimes on soil health and crop productivity. Three cattle grazing regimes (mid-February, mid-March, and mid-April cattle removal dates) and an ungrazed control were included in a randomized complete block design and replicated three times. Chemical soil health indicators (soil organic carbon, permanganate oxidizable carbon), physical soil health indicators (water stable aggregates, penetration resistance), biological soil health indicators (microbial biomass carbon, arbuscular mycorrhizal fungi colonization), crop yield, and cover crop biomass were evaluated. Cover crop biomass at termination was reduced for all grazed treatments compared to the ungrazed control, and the mid-March and mid-April treatments resulted in the lowest amount of cover crop biomass. No treatment effects were observed for arbuscular mycorrhizal fungi, microbial biomass carbon, and permanganate oxidizable carbon. Soil organic carbon was higher in the ungrazed treatment than the mid-April grazing treatment. Penetration resistance was significantly higher for the mid-April treatment compared to the ungrazed treatment. Water stable aggregates were higher in the ungrazed treatment than the mid-March and mid-April treatments. The results from this study suggest that longer cover crop grazing periods have little effect on biological and chemical soil health indicators in the short term, but can negatively impact some physical soil health indicators. Shorter grazing periods allowed for regrowth of cover crop biomass, leaving more residues to prevent soil erosion and reduce soil compaction.