Hairy Vetch Kill Date Effects on Soil Water and Corn Production
1995
Clark, Andrew J. | Decker, A Morris | Meisinger, John J. | Mulford, F Ronald | McIntosh, Marla S.
Hairy vetch (Vicia villosa Roth) can fix N₂ for subsequent release to a corn (Zea mays L.) crop, but kill date effects on vetch N accumulation, soil water, and subsequent corn production have not been studied. A hairy vetch cover crop can deplete soil water through transpiration, but cover crop mulches can conserve soil water for no-till corn. In order to determine optimum spring kill date and corn fertilizer N (FN) rates, hairy vetch was killed early April, late April, or mid-May, followed by three corn planting dates and four FN rates (0, 45, 135, and 202 kg N ha⁻¹). From early April to mid-May, hairy vetch aerial phytomass and N content increased significantly, from 2800 to 4630 and 96 to 149 kg ha⁻¹, respectively. Corn grain yields ranged from 5.2 to 10.1 Mg ha⁻¹ and were significantly greater following mid or late kill, compared with early kill of vetch, regardless of corn planting date or FN rate. Gravimetric soil water under mid- or late-kill vetch was often significantly greater than after early-kill vetch. We conclude that soil water conservation by late-killed vetch mulches had a greater influence on corn production than vetch spring water use. Optimum N production and water conservation occurred when vetch was killed the last week of April. Earlykill vetch sacrificed N production and minimized soil water conservation, resulting in reduced corn grain yield. Late kill did not add significant N benefits, but could deplete soil water or interfere with timely corn planting. Contribution no. 8777. Scientific Article no. A6565. Maryland Agric. Exp. Stn.
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