Agronomic and Economic Comparison of Full-Season and Doublecropped Small Grain and Soybean Systems in the Mid-Atlantic USA.

Doublecropping soybean after wheat is the predominant small grain crop rotation in the Mid-Atlantic.  Increased barley demand provides the opportunity for newer and more diverse cropping systems.  Very little information is available comparing a barley-soybean to either wheat-soybean or full-season soybean systems.  Field studies were conducted at four sites in Virginia during 2008 through 2010 to determine yield and profit of four cropping systems that include: fallow full-season soybean, rye cover crop- full-season soybean, barley-soybean, and wheat-soybean.  In 2009, wheat and barley yields ranged from 1,680 to 4,435 kg ha^-1 and 3,978 to 6,235 kg ha^-1, respectively.  At two of four locations, yields for both full-season soybean and soybean following barley were greater than soybean following wheat.  Full-season soybean averaged 3,622 kg ha^-1 and 3,816 kg ha^-1, and barley-soybean averaged 3,615 kg ha^-1 and 4,038 kg ha^-1, respectively.  At these two sites, yields of full-season soybean and soybean following barley were 410 kg ha^-1 and 604 kg ha^-1, and 94 kg ha^-1 and 517 kg ha^-1 greater than soybean following wheat, respectively.  A breakeven sensitivity table was created using yields and prices.  The net returns from the barley-soybean cropping system were competitive with both the wheat-soybean and the full-season soybean cropping systems.