Theses and Dissertations
ORCID
https://orcid.org/0000-0003-1294-2145
Issuing Body
Mississippi State University
Advisor
Baker, Beth
Committee Member
Brooks, John P.
Committee Member
Locke, Martin A.
Committee Member
Morin, Dana J.
Committee Member
Brown-Johnson, Ashli
Date of Degree
5-13-2022
Document Type
Dissertation - Open Access
Major
Forest Resources
Degree Name
Doctor of Philosophy (Ph.D)
College
College of Forest Resources
Department
Department of Wildlife, Fisheries and Aquaculture
Abstract
The transition of natural landscapes to intensive agricultural uses has resulted in severe loss of soil organic carbon (SOC), increased CO₂ emissions, river depletion, and groundwater overdraft. Despite negative documented effects of agricultural land use (i.e., soil erosion, nutrient runoff) on critical natural resources (i.e., water, soil), food production must increase to meet the demands of a rising human population. Given the environmental and agricultural productivity concerns of intensely managed soils, it is critical to implement conservation practices that mitigate the negative effects of crop production and enhance environmental integrity. In the Mississippi Alluvial Valley (MAV) region of Mississippi, USA, the adoption of cover crop (CC) and no-tillage (NT) management practices has been low because of a lack of research specific to the regional nuances. Therefore, this study assessed the long-term soil physiochemical and biological responses from integrating CC and NT management to agricultural soils of the region. Research plots were established in a split-block design with two tillage treatments: NT and reduced tillage (RT) and three CC treatments: no cover (NC), rye (RY) and a rye+clover (RC) mix. Soil samples were taken during the growing season of 2019 and 2020. Bulk density was found to be significantly lower in NT plots and aggregate stability was greatest in plots with a single CC species. Moisture retention increased in NT.. Soil organic carbon was greater in NT and CC treatments and there was no difference in CO₂ flux. Bacterial abundance had a positive effect on SOC but a negative effect on CO₂. The rate of proportional change and pattern of variability in C pools suggested loss of SOC in reduced tillage (RT) treatments. Microbial abundance, functional genes and enzyme activity was greater in NT with CC, but diversity was greater in RT. No-tillage practices lower diversity and influence long-term community changes while CC practices enact a seasonal response to environmental conditions. I conclude that in heavy clay soils of the mid-South region of the MAV, RT with a CC is optimal for soil health traits associated with crop sustainability, however the management will still contribute to increased CO₂ emissions.
Recommended Citation
Firth, Alexandra Gwin, "Evaluating soil health changes following cover crop and no-till integration into a soybean (Glycine max) cropping system in the Mississippi Alluvial Valley" (2022). Theses and Dissertations. 5499.
https://scholarsjunction.msstate.edu/td/5499
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Agriculture Commons, Applied Statistics Commons, Biodiversity Commons, Bioinformatics Commons, Environmental Health Commons, Environmental Microbiology and Microbial Ecology Commons, Multivariate Analysis Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Sustainability Commons, Water Resource Management Commons