Parr, M., J. M.Grossman, S. C. Reberg-Horton, C. Brinton and C. Crozier. 2014. Communications in Soil Science and Plant Analysis
Nitrogen (N) release from roll-killed legume cover crops was determined for hairy vetch (Vicia villosa Roth), crimson clover (Trifolium incarnatum L.), and a hairy vetch rye (Secale cereale L.) biculture in an organic corn production system in North Carolina. Cover crops were planted at two locations in fall 2008 and 2009, roll-killed in May, and no-till planted with corn (Zea mays L.). Inorganic soil N and mineral N flux were determined using potassium chloride (KCl) extractions and ion exchange resin (Plant Root Simulator, PRS™) probes at two-week intervals for 12 weeks and compared to fertilized controls of 0 and 168 kg N ha-1. In 2009, greater plant available N under hairy vetch than under either 0N control or crimson clover was found, with peak soil N occurring between 4 and 6 weeks after roll kill. Available soil N under crimson clover mulches was lower than or equal to 0 N, suggesting net immobilization.
legume cover crops, N mineralization, organic cropping systems, N synchrony, nutrient cycling, Vicia villosa , Trifolium incarnatum
