Understanding the Effect of Fall Planting Date on Four Cover Crops.

Three different crop species planted on five dates spanning two months at three locations across the state of Minnesota conducted in both 2006-2007 and 2007-2008. The crop species include winter rye (Rymin), spring rye (Gazelle), triticale (NE426GT), and winter wheat (Jerry). These species were selected because they represent a differing range of winter hardiness, spring rye, winter wheat, triticale and winter rye, listed from least winter hardy to most winter hardy. Planting dates were 25 August, 5 and 20 September, and 3 and 24 October. These dates represent the range in time when a fall-planted cover crop would most often be seeded in Minnesota. The three MAES locations spanned the state from Roseau (49oN lat) in the north, to St. Paul (45oN lat) and Lamberton (44o20'N lat) in the south. Fall plant height, canopy closure, aboveground biomass and nitrogen uptake were assessed. In the spring crop growth and development, with specific emphasis on growth stages up to anthesis, were monitored. Planting date has a substantial influence on biomass production and nitrogen uptake, and a small influence on anthesis date. Also, there was a clear location by species by growth stage interaction.