Quantifying Soil Health from Soil Organic C and N Fractions in Diverse Winter Cover Crops in North Carolina.

Agricultural sustainability is linked to soil health. Long-term change in soil health from the use of single-species cover crops is evident in the literature, but how soil health changes with multi-species cover crops is not known, particularly in the North Carolina Coastal Plain. We hypothesized that greater above ground plant diversity would increase the variety of available substrates below ground, which would in turn increase the function of soil microbial communities. High functioning soil microbial communities serve as indicators of soil health due to their key role in cycling of nutrients, formation of aggregates, and promotion of root proliferation, among other functions. Research was conducted on four farms in the NC Coastal Plain, one farm in the NC Piedmont, and two small plot trials at the Cherry Research Farm in Goldsboro NC and the Peanut Belt Research Station in Lewiston-Woodville NC. Soil organic C and N fractions were determined from total, particulate, and mineralizable C and N. Surface residue C and N contents were determined as well. Small-plot trials with one-, two-, three-, and six-species mixes were conducted to help support findings from the on farm demonstration plots. We expect to see improved soil biological activity and nutrient cycling due to diversity of cover crop mixes. Our goal is to build soil health and agricultural sustainability for cash-crop production systems, and if multi-species cover-cropping contributes to these goals, to promote their utilization.