Effects of depth and cover crop treatment on the functioning and diversity of soil microbial communities

View the project final report

Commodities

Practices

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

Effects of depth and cover crop treatment on the functioning and diversity of soil microbial communities

Global agriculture continues to be strained by the unpredictable effects of climate change, including flooding, drought, erosion, and decreases in soil fertility.  To counter these changes, global agricultural systems must develop new techniques while promoting sustainable intensification practices. Cover crops can provide farmers with an off-season cash crop, while also positively impacting the soil and reducing reliance on less sustainable conventional farming practices.

The objective of this research is to evaluate the impact of different cover crops on soil microbial communities at varying depths.  Cover crops have the potential to facilitate nutrient cycling, increase soil organic matter and nitrogen fixation, maintain topsoil, and improve weed control, but basic questions regarding cover crop effects on the soil microbial community so integral to these responses remain to be answered.  Depth is an important factor in evaluating the effectiveness of a cover crop to build soil organic carbon.  Traditional sampling methods homogenize the top 6 inches of soil, which often does not show significant changes in organic carbon year to year.  I propose to conduct community-level physiological profiling (CLPP) at three depths to test the hypothesis that cover crop type and soil depth are strong determinants of microbial community diversity and functioning in an agricultural field.  I predict: (a) that the physiological profile of the microbial community, as measured by the rate and ability to metabolize a variety of carbon sources, will change across depths and differ between cover crop types, and (b) that the overall functional diversity of the microbial community will be greater under cover crop treatment than without.

This project will inform local farmers on the benefits of cover crops to the overall health of their soils and productivity of their crops.  Greater adoption of cover crops and more sustainable stewardship of our croplands will be encouraged through conversations with central Illinois farmers at Illinois State University farm days.  Additionally, this research will be presented at a national meeting and the findings will be presented in a peer-reviewed publication.  Undergraduate students will help with field collection and analysis of samples.  This will offer an avenue to explore new techniques that are not part of the curriculum and give these biology students the opportunity to work across disciplines with researchers from the Agriculture Department and local farmers.

The proposed research will answer basic questions about plant-microbial interactions in soils through the examination of a managed system. This research will contribute to a larger body of knowledge about the relationship between plants and soil microbes and their effects on our croplands.  Additionally, this research will be presented at a national meeting and the findings will be presented in a peer-reviewed publication.  Undergraduate students will help with field collection and analysis of samples.  This will offer an avenue to develop new skills and learn techniques that are not part of the curriculum and give these students the opportunity to work across disciplines with researchers from the Agriculture Department and local farmers.

Community outreach will be performed through farm days at the Illinois State University Farm.  These events bring in local farmers to hear about research being conducted at the University Farm.  These events will give me a unique opportunity to gain the perspective of the people who will be directly impacted by my research and to foster a positive relationship between researchers and farmers.  Through conversations with local farmers, I will explain what my study means for their practices, how the choice of cover crops could affect the overall health of their soils, and how certain over crops can also provide added income.  These activities will encourage greater adoption of cover crops in central Illinois farmlands.  The knowledge gained through this project will complement ongoing projects at ISU, which together will demonstrate the value of cover crops.