Relay Cropping in Winter Barley Feasibility.

Relay-Cropping in Winter Barley Feasibility.  Brad Brown.  University of Idaho, Parma R&E Center.

Winter barley, with earlier maturity, has potential for relay-cropping warm season oilseeds, forages, or grain in western Idaho and the Columbia Basin.  Preliminary studies were conducted at the Parma R&E Center in 2009-2011 to evaluate the feasibility of relay cropping in furrow irrigated winter barley.  Soybeans (relative maturity group 0.8), corn (87 day maturity), sunflower, and grain sorghum were relay planted in mid May between 14 inch spaced winter barley rows on 30 inch beds.  Acceptable soybean stands were obtained in all years but corn, sorghum,  and sunflower stands were largely gone from pheasant, quail or mice seed or seedling depredation in all years.  Maja barley yield averaged 140 bu/A in 2009, only 80 bu/A in 2010 due to early season moisture stress, and 119 bu/A in 2011.  Soybeans matured by October in all years and yields in harvested plots with poorer to acceptable stands ranged from 14 to 36 bu/A in 2009, only 6 to 15 bu/A in 2010 due to clipping of soybean tops during the barley harvest, and 21 bu/A after moderately tall Maja barley and 31 bu/A after a short OR912 barley in 2011.  Relay soybeans were stunted.  Major limitations for soybean yield may have included drought during barley maturation, poor light conditions during early growth, wider than optimal row spacing, and possibly the soybean maturity class.  Sufficient heat units are available with relay cropping in winter barley to mature short season soybeans, corn, sunflowers, and possibly other commodities in Idaho’s Treasure Valley.  The project revealed many of the challenges relay cropping in winter barley will present, and the greatest for small scale study was seed depredation.