For the past two decades, however, U.S. barley acres have declined, largely because prices were well below $2 per bushel. In the mid-Atlantic region, the acreage decline was accompanied by weakening feed demand as larger operations replaced small farms that once raised barley for their own on-farm feed needs. While barley has a better balance of amino acids than corn, the hull and its high fiber and beta-glucan content limit its use in poultry and swine diets. A relatively cheap, plentiful corn supply available for import from the Midwest helped to move barley into the shadows as a feed crop. Consequently, U.S. production dropped from a high of more than 590 million bushels in the mid-1980s to 180 million bushels in 2006. Lately, however, production has increased as prices have reached $5.40 to $6.40 per bushel. In fact, USDA forecasts 218 million bushels of barley will be produced this year.
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Virginia producers planted 28 percent more acres in response to last year’s higher prices, says Wade Thomason, Virginia Tech extension agronomist. Barley has potential as an ethanol feedstock because it is a better option than winter wheat for double cropping with soybeans, he explains. Barley’s early maturity allows it to be harvested a couple of weeks before wheat in the spring. That has a significant impact on the soybean crop that’s planted after the harvest. “Planting after the first of May you lose one-half bushel per day in soybean yields,” Thomason explains. The earlier barley harvest allows for earlier soybean planting, which can lead to a four to 10 bushel per acre increase in yields.
Additionally, barley is a low-input crop that requires 30 to 40 pounds of nitrogen per acre in the fall; if needed more nitrogen can be top-dressed in the spring. With good management, producers are getting 130 to 140 bushels per acre, although the state average yield is in the mid-80 bushels per acre, Thomason says. Average yields are brought down by growers who plant barley primarily as a cover crop, which requires minimal management. Depending on the stand, the farmer may harvest it for grain before seeding the summer crop. Barley yields in Virginia compare with average corn yields of 120 bushels per acre and 200 bushels on the top end, he adds. Corn yields are often hurt because the region’s soils can’t hold enough moisture to carry it through hot summer days when rains can’t make up for high evaporation and transpiration rates.
Breeding Better Barley
Barley breeders have made great strides to improve the crop’s performance, focusing on heavier test weights and the development of hulless varieties. “We needed to make the grade for international markets as well as local feed markets,” Thomason explains. Older varieties would often respond to poor harvest weather or dry spells by producing light, 43- to 45-pound test weight grain. Test weights for the new hulled varieties are coming in at the mid-50s while the hulless varieties are approaching 60 pounds per bushel.
In breeding hulless varieties, Virginia Tech researchers address barley’s limitations. The hulls, which make up 12 percent to 15 percent of the kernel weight, are a non-nutritional component that make barley less desirable in poultry or swine rations, and its high silica content is abrasive to milling equipment. While barley is often hulled, or pearled, Virginia Tech researchers have developed hulless cultivars with a loosely attached hull that is easily lost during harvest.
Other issues have surfaced when considering barley as an ethanol feedstock. “Barley isn’t usually thought of as a good candidate for fuel ethanol feedstock because it typically has an abrasive hull and a lower starch content than corn,” says Kevin Hicks, research leader of ERRC’s Crop Conversion Science and Engineering Research Unit. “And it contains a troublesome polysaccharide, beta-glucan, which makes barley mash too viscous to mix, ferment and distill economically.” The low-starch content in older barley varieties—50 percent to 55 percent compared with corn’s 72 percent—results in lower ethanol yields. The newer hulless varieties developed at Virginia Tech, however, are achieving starch content closer to 60 percent.
In addition, researchers have been trying to break down the 3 percent to 7 percent beta-glucan content of barley into fermentable sugars. Hick’s team at ERRC is collaborating with Genencor, a division of Danisco, to develop enzymes that will do the job. The Europeans have long used beta gluconase enzymes to reduce the viscosity of barley in ethanol plants, says John Nghiem, a crop conversion scientist and chemical engineer at ERRC. The team has identified a second enzyme to break down the beta-glucan more completely, boosting ethanol yields by converting the problematic beta-glucan. They have achieved ethanol yields of 2.05 gallons per bushel using the popular hulled variety called Thoroughbred, and 2.41 gallons per bushel using one of the hulless varieties.
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