Mar Horns

Cover crop research has the potential to unlock environmental benefits such as increased soil fertility and weed suppression in organic agricultural systems. Variation between methodology can affect results, and planting methods are often different from study to study, even though planting methods can have vastly different seed-to-soil contact and depth of sowing. There is currently a lack of research on the effect of planting methods on cover crop performance. This study was conducted to evaluate differences between 3 planting methods; broadcast by hand, a hand-pushed seed drill, and a tractor-drawn seed drill. Three leguminous cover crop species, sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), and berseem clover (Trifolium alexandrinum), were sown with each planting method in 4 randomized blocks and grown for a 6-week midsummer trial typical of intensive vegetable production systems. Stand counts were taken at 1, 2, and 4 weeks after planting. Earlier germination was favored by the tractor-drawn drill, while later stand counts were highest in broadcast plots. At termination, biomass and soil samples were taken from each plot, from which permanganate oxidizable carbon (POX-C) was measured to evaluate soil organic matter and potentially mineralizable nitrogen (PMN) was measured to evaluate soil fertility. There was no significant difference in POX-C and PMN across planting methods or cover crops. Weed biomass was not reduced by either treatment as compared to the fallow control. Despite the difference in stand counts, planting method does not appear to affect final soil additions or weed suppression in short duration cover crops.