Crop of the Week: Sweet sorghum

  • Food, feed and fuel are three of the necessities of life but it is not often that all three requirements can be provided by one crop. Sweet sorghum not only provides grain for human consumption and stalks and leaves for fodder, but it is increasingly being known as a "smart" multipurpose crop and is now recognized as a potential crop for the production of ethanol.

  • Sweet sorghum is a corn-like plant that can grow as high as an elephant's eye on some of Earth's driest farmland and shows promise as a biofuel that would not cut into world food supplies. The 10-foot stalk can be turned into ethanol without damaging the food grain that grows at the top of the plant.

  • Unlike corn-based ethanol, which uses 1.5 times as much energy in its production, sweet sorghum produces eight units of fuel for every unit of fuel used to grow it. The high levels of different sugars in sweet sorghum juice are beneficial to the rate of alcohol production.

  • Yuma County producers are seeking alternative cropping systems and sweet sorghum could be one potential crop on the horizon. Sweet sorghum grows well in Arizona because it doesn't require excessive irrigation and can survive long, hot summers. The crop would be grown primarily for ethanol production, the by-products, such as sorghum distillers grain, would also find a place in the market as animal feed.

  • African slaves introduced the crop, which then was known as "Guinea corn," into the United States in the early part of the 17th century. Sweet sorghum has been widely cultivated in the U.S. since the 1850s for use in sweeteners, primarily in the form of sorghum syrup. By the early 1900s, the U.S. produced 20 million gallons of sweet sorghum syrup annually.

  • Sweet sorghum is relatively inexpensive to grow with high yields and can be used to produce a range of high value-added products like ethanol and distillers dried grains. It can produce over 12 dry tons an acre per year of biomass on low quality soils with low inputs of fertilizer and water and is relatively drought resistant.

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Source: Kurt Nolte is an agriculture agent and Yuma County Cooperative Extension director. He can be reached at knolte@cals.arizona.edu or 726-3904.