Date on Master's Thesis/Doctoral Dissertation

12-2021

Document Type

Master's Thesis

Degree Name

M.S.

Department

Interdisciplinary and Graduate Studies

Degree Program

Interdisciplinary Studies (Individualized Degree), MS

Committee Chair

Sluss, Tamara

Committee Member

Lackey, Alycia

Committee Member

Haramoto, Erin

Author's Keywords

no-till; rye; cover crop; AMF; soil microbes

Abstract

Nutrient levels and aggregation measurements are currently the most accurate means to measure soil health. It has been suggested that bacterial and fungal communities may prove to be a more accurate measure of soil health. In this study soil microbe communities and nutrient levels were compared in rye cover cropped soils to measure for differences between treatments. Effects between the microbial communities and environmental measurements were also measured within those treatments to test for correlations between soil health measures and microbial communities. The plots were put in a biennial corn (Zea mays L.) and soybean (Glycine max) rotation in 2015, with corn planted in 2020. Cereal rye was examined as the cover crop, compared to bare soil plots, and weedy fallow plots. Available nutrient levels of phosphorus (P), potassium (K), Calcium (Ca), magnesium (Mg), and zinc (Zn) were measured, as well as nitrate levels, ammonium levels, temperature, pH, and volumetric water content (VWC). Bacterial and fungal diversity measures and taxonomic families were compared between treatments. Rye soils were observed to have significantly higher levels of VWC in 2” soil depth while annuals were observed to have significantly higher levels in 6” soil depth. Although there were no significant differences in diversity measures, rye soils had significantly more organisms in the AMF family Pleosporaceae as well as Helotiales Incertae sedis, and Diversisporaceae fungal families, while bare soil showed an increase in the Microdochiaceae family. Further research is discussed to understand possible fungal influence on rye cover cropped soils.

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