Living Soil for a Sustainable Future: Assessing the Effects of Cover Crops and Tillage on the Soil Microbial Community and Health

View the project final report

Commodities

• Vegetables: greens (lettuces)

Practices

• Crop Production: cover crops
• Soil Management: soil microbiology

Agricultural land management practices influence the physical, chemical, and biological characteristics of soil, including the structure of the community of microorganisms present in the soil, which in turn, directly influences processes such as nutrient cycling and water infiltration and retention, which ultimately shape the long-term health and fertility of an agricultural landscape. The purpose of this study was to examine the effects of cover cropping and tillage practices on the function and structure of soil microbial communities that contribute to soil health. We worked with four farmers in Virginia and conducted studies at the eastern Shore AREC to assess the impact of various practices on the structure and function of the soil microbial communities. Soil samples from field/plots with/without cover crops of varying species (legumes, grasses, brassicas and legume/grass/brassica mixtures) and till/no-till practices were sequenced for microbiome determination. We also examined how cover crops influence soil microbial activity (respiration), N mineralization and fertility, and the performance of the subsequent crop (lettuce). The results of this study generated information on how cover crops, which are becoming increasingly common in the Southern region, influence soil function, and fertility. Legume cover crops increased soil respiration, N mineralization and availability, and performance of the subsequent crop. In contrast, sorghum sudangrass reduced soil respiration, N mineralization and availability, which was reflected in the poor performance of the subsequent crop. The information generated in this study were extended to farmers and peers through field days and conferences presentations for decision making in selecting the appropriate cover crop species. Understanding how cover crops enhance the soil microbial functioning and health, will improve agricultural sustainability.

1. To determine how cover crops and tillage practices impact the structure and function of the soil microbial community.
2. To determine how cover crops relate to soil characteristics, fertility (i.e. soil organic matter, total carbon and N content, N mineralization rate, and fertility).
3. To determine the influence of cover crops on the subsequent cash crop growth and production.
4. To disseminate our findings to a wider audience of farmers, researchers, and others in a practical and meaningful way.