How Do Soil Microbes Respond to Chickpea Replacing a Bare Fallow Period in Southeastern Row Crop Agroecosystems?

Florida agroecosystems are mostly established on coarse-textured soils and subject to a hot and humid climate that favors rapid soil organic matter decomposition, water percolation, and nutrient leaching. Cover crops can replace fallow periods and help protect and improve soil conditions, but the adoption of cover crops is limited because they are usually not profitable. Chickpea is a short-season, cool-season legume crop that could be used as an alternative as it fits the rotation gap. Moreover, chickpea can increase soil cover and increase crop residues while being more economically attractive as it can be harvested, serving as a dual-purpose (i.e., cash and cover) crop. Replacing a bare fallow with chickpea could also benefit soil biology, as the greater amount of crop residues returned to the system should stimulate microbially-driven carbon and nitrogen cycling. Greater microbial activity is critical to soil health because microbes decompose residues, stimulate plant growth, and increase nutrient cycling and availability. As the microbial community is responsive to management practices and provides information on microbially-driven nutrient cycling, microbial indicators could help assess agroecosystem sustainability and predict possible crop benefits, such as improved yield and/or nutrient use efficiency. This project aims to assess how replacing winter fallow periods with chickpea in row crop agroecosystems of the Southeast US affects soil microbes. More specifically, our goal is to quantify how chickpea, other cover crops and fallow affect soil carbon mineralization, enzyme activity, and gene expression, to determine the impacts of different winter crops on agroecosystem sustainability.