Soil microbiomes in three farming systems more affected by depth than farming system

Authors: SCHMIDT, DIETRICH EPP - University Of Maryland; DLOTT, GLADE - Stanford University; Cavigelli, Michel; YARWOOD, STEPHANIE - University Of Maryland; Maul, Jude

Submitted to: Applied Soil Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2022
Publication Date: 1/29/2022
Citation: Schmidt, D., Dlott, G., Cavigelli, M.A., Yarwood, S., Maul, J.E. 2022. Soil microbiomes in three farming systems more affected by depth than farming system. Applied Soil Ecology. 173:104396. https://doi.org/10.1016/j.apsoil.2022.104396.
DOI: https://doi.org/10.1016/j.apsoil.2022.104396

Interpretive Summary: The top meter of soil stores gaseous forms of carbon, CO2 and CH4, which are primary drivers of climatic temperature and weather patterns. We used a long-term agricultural research site to determine the impacts of farming system (crops, rotation and fertility inputs) on the structure and function of the soil microbial community responsible for changes in soil carbon pools. Molecular biological approaches were used to extract DNA and enzymes from the soils of different farming systems in 10 cm increments to 60 cm. We found that diversity and abundance of bacterial and fungal indicator genes differed among No-till and Tilled Organic farming systems, and that fungi were more abundant and more evenly distributed in the surface 30 cm in Organic systems than Conventional No-Till systems. At and below 30cm, differences in microbial community structure were observed which showed that land managers choice of farming system can have an impact on the soil microbiological community well below the depths that are directly managed by farming operations. This information is valuable because it provides insight into the volume of soil that is impacted by surface level management. Understanding the depth of the affect surface management is having on microbes and soil biological processes will help data analysts build more accurate predictive models for soil carbon sequestration.

Technical Abstract: Management of the soil surface is necessary for productive farming systems and provides an opportunity to create soil systems that have a greater capacity to store CO2 and CH4, primary drivers of climate change. We use a long-term agricultural research site to understand the impacts of farming system design (crops, rotation and fertility inputs) on the structure and function of the soil microbial community responsible for changes in soil organic matter pools. Soil DNA and enzymes were extracted from No-Till, Chisel-Till and Organic Corn-Soy-Wheat farming systems in 10 cm increments to 60 cm. Ribosomal ITS and 16s genes differed among No-till and Tilled Organic systems, and fungi were found to be more abundant and more evenly distributed in the surface 30 cm in Organic systems than Conventional No-Till systems. The phylogenetic functional predictor tool PiCrust was used to detect functional difference in fungal lignin and carbohydrate degradation pathways below the plow layer. This information is valuable because it provides insight into the volume of soil that is impacted by surface level management. The depth to which the affect surface management has on soil biological processes will help data analysts build more accurate predictive models for soil carbon sequestration.