Location: Soil Dynamics ResearchTitle: Responses of biological soil health indicators to cover crop mixtures in a conservation agricultural system
|UCAR, GOKHAN - Auburn University|
|FENG, YUCHENG - Auburn University|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/3/2019
Publication Date: 11/13/2019
Citation: Ucar, G., Feng, Y., Balkcom, K.S. 2019. Responses of biological soil health indicators to cover crop mixtures in a conservation agricultural system[abstract]. ASA-CSSA-SSSA Annual Meeting. CD ROM.
Technical Abstract: Few data are available demonstrating the benefits of planting more than one species of cover crops in the southeastern U.S.; even less is known about the response of soil biota. We examined the effects of three winter cover crop species grown separately and in combination on selected biological indicators of soil health and determined how these indicators changed in a cotton (Gossypium hirsutum L.)–soybean (Glycine max L.) rotation under strip tillage over a three-year period. Twelve treatments, comprised of each single species and mixtures of cereal rye (Secale cereale L.), crimson clover (Trifolium incarnatum L.), and radish (Raphanus sativus L.), were arranged in a randomized complete block design with four blocks. Biological indicators were measured across a subset of treatments that included fallow, rye alone, rye/clover, rye/radish, clover/radish, and rye/clover/radish mixtures. Soil microbial biomass C and arbuscular mycorrhizal fungi (AMF) colonization of cotton roots were analyzed in the spring; active C, soil respiration, and glomalin-related soil protein were analyzed in the fall. In the first two years, significant treatment differences were found only for the AMF colonization of cotton. In the third year, overall treatment effects were found for all of the indicators measured; however, there were no significant differences among cover crop types. Our results show that the beneficial effects of cover crops on biological soil health became more pronounced over time. Active C, soil respiration, and AMF colonization were indicators of short-term changes; AMF colonization of cotton responded to cover cropping most quickly. Within the three years, biological indicators measured did not improve as the number of cover crop species increased. A longer duration of cover crop treatments may be needed to detect the effects of cover crop mixtures on soil biota.