Winter Grain - Silage Corn Double Crop System for New England.

Organic dairy production is a growth area of Northeast agriculture, but sustainability is largely dependent on growers producing quality feed and minimizing weed pressure. Due to high feed costs, producers must maximize on-farm forage and grain production. Growers must decide when to harvest grains (at boot or soft dough stage) and what type of corn to plant to maximize yield and quality. The first year of a five site-year trial was initiated in Maine in 2007. Winter wheat, spelt, winter triticale and winter barley were planted 20 September 2007. Yield estimates and weed biomass were taken at boot or soft dough, and hybrid or open pollinated corn was planted immediately after harvest. A full season corn treatment was included for comparison. Differences were found in small grain yield and quality. While high yielding, spelt was two weeks later maturing, had poorer forage quality, and as such will be dropped from future trials. Delaying small grain harvest to soft dough stage significantly increased small grain yields but reduced corn yield. Winter barley had significantly better forage quality (all parameters), but some winter kill lowered yield and forage quality yield. Full season corn yielded 2.1 and 3.8 Mg ha-1 higher than the double crop corn, but the double crop winter wheat/corn double crop produced 14.4 Mg ha-1 compared to 10.2 Mg ha-1 for full season corn. We found higher yields with corn planted after boot stage harvest than soft dough, but we found little difference in yield between hybrid and open pollinated corn. Due to timely cultivation, weed pressure in the full-season corn was equivalent to that in the double crop combinations. Overall yield and forage quality was significantly improved in the double crop combinations compared to full season corn. Data from two additional (Maine and Vermont) site years will be presented.