Diverse and High-Residue Cover Crops for Mid-Atlantic Production Systems.

On the coastal plain of Virginia, sandy loam soils generally contain low organic matter (~0.5%) concentrations and may be conventionally tilled depending on crops in rotation. The overall goal of this project was to document benefits of transitioning land from traditional high intensity and low biomass production to systems utilizing high-residue, diverse cover crop species, or alternative summer cover crops. In fall 2014, we initiated a long-term study testing 12 different treatments that host a combination of cash crop sequence changes and cover crop species; which were compared to a conventionally tilled corn monoculture. Species ranged from no-cover to cover crop mixes with 9 different species present; which contained different functional groups (i.e. nitrogen (N) scavenging, N producing, and tillage). We will quantify potential soil quality improvements and nutrient cycling by measuring total biomass produced, total carbon (C), total N, and total sulfur (S) accumulation. In December prior to winter kill, biomass from plots ranged from 113 to 1137 kg biomass ha^-1. By desiccation in late April, aboveground biomass ranged from 2054 to 9215 kg biomass ha^-1. Mixed species cover crops and cereal rye had more biomass produced, and N and S accumulation than other treatments. In conclusion, cover crop mixes may provide more biomass additions to sandy loam soil production systems to increase overall soil organic matter concentrations and nutrient cycling than traditional cover crop systems.