Corn and cover crop response to corn density in an interseeding system

The increasing cost of nitrogen fertilizer and the need for a N source for low-input and organic farmers have led to the increased exploration of legume cover crops as an alternative to N fertilization. Reliable cropping strategies are needed to enhance legume cover crop use as a N source. Interseeding legume cover crops into corn (Zea mays L.) can affect corn yield and cover crop dry matter. This study, conducted at the Kellogg Biological Station in Hickory Corners, MI, from 2002 to 2005, evaluated (i) the impact of interseeded cover crops on corn yield at various corn densities (37,500 to 75,000 plants ha-') and (ii) the effect of corn density on cover crop dry matter (DM) when corn was interseeded with red clover (Trifoliumpratense L.) or chickling vetch (Lathyrus sativus L., var. AC Greenfix). Interseeded cover crops did not affect corn yield at any corn density. Interseeded cover crop DM decreased as corn density increased. The subsequent spring, red clover DM was similar regardless of previous corn density; AC Grecnfix did not regrow. Interseeded cover crops produced less DM than monoculture cover crops. Cover crops can be interseeded into corn densities up to 75,000 plants ha(-1) without corn yield reduction and still produce substantial DM the subsequent spring. Interseeding corn with red clover could be used in low-input farming systems to reduce N fertilizer costs, especially in developing countries and in organic farming systems.