Yield Potential of Alternative Cropping Systems for Organic Dairy Farms.

Organic dairy systems continue to play an important role in transformations of agriculture in the Northeast U.S.  In general, cropping systems on organic dairies are distinct from their conventional counterparts, having greater reliance on pasture, a more diverse crop mix, and minimal on-farm grain production.  Field experiments were established in Orono, ME, in 2006 and 2007, to evaluate four production scenarios on organic dairy farms in the Northeast U.S.: 1) corn (Zea mays L.) silage with grain production; 2) corn silage without grain; 3) no corn silage with grain; and 4) no corn silage or grain.  Sorghum-sudangrass hybrid [Sorghum bicolor (L.) Moench] and triticale (Triticosecale) harvested at either boot or soft dough stage substituted for corn as a forage source, and grains included barley (Hordeum vulgare L.), high-moisture corn, soybean [Glycine max (L.) Merr.], and triticale.   Crop yield, dry matter (DM), energy and protein concentration were measured for all crop harvests.  Yield and quality varied widely among these crops.  As expected, yield of each crop fluctuated from one year to the next, but relative yields across crops were consistent.  For example, corn silage yield ranged from 9200 to 14000 kg DM ha^-1 across years, was and were generally more than twice the yield of sorghum-sudangrass (3600 to 5000 kg DM ha^-1, harvested twice), and about six to eight times the yield of triticale harvested at boot stage (1200 to 1800 kg DM ha^-1).  Yield of barley, soybean, and triticale grain in these organic systems was similar to conventional grain production in Maine.   This research helps organic dairy farms select crops and production systems appropriate for their farms.