by Jeri Stroade, former extension assistant, and Michael Boland, professor, Department of Agricultural Economics, Kansas State University, mboland@agecon.ksu.edu.
Profile reviewed August 2008.
Overview
Sorghum (Sorghum bicolor), also known as milo, has a variety of uses including food for human consumption, feed grain for livestock and industrial applications such as ethanol production. The area planted to sorghum worldwide has increased by 66 percent over the past 50 years, while yield has increased by 244 percent. Around half of the sorghum produced is fed to livestock, and half is consumed by humans and used in other applications. Currently, most human consumption of sorghum occurs in low-income countries, while high-income countries typically use sorghum as a component in livestock feed. Sorghum is a versatile plant because it can tolerate drought, soil toxicities, a wide range of temperatures and high altitudes. Since 25 percent of the population is expected to undergo severe water shortage by 2025, the crop’s adaptability suggests that it may soon play a larger role in supplying the world with grain.
Value-added Products
Globally, about 50 percent of sorghum is consumed by humans, but in the United States over 90 percent of the sorghum consumed is used as a component in livestock feed. Corn is the main substitute for sorghum in livestock feed. The starch and protein in sorghum are more difficult for animals to digest than those in corn, giving corn a distinct advantage for feed usage. However, research is being conducted to develop processing methods that allow animals to digest sorghum more readily. Processing breaks the seed coat, reduces particle size and increases surface area. Some methods of processing make the end-use value of sorghum comparable to that of corn because more starch and protein are able to be digested in sorghum.
While many new sorghum food products are currently being developed, the grain’s food use has been limited thus far. These limitations are mainly due to two characteristics of the plant. First, phenolic acid and tannins cause flour made from sorghum to have a bitter flavor. Second, the lack of gluten restricts sorghum’s usefulness in the food industry. Recently a food-grade sorghum was developed that does not contain phenolic acid or tannins, and thus, the resulting flour does not have a bitter taste. These varieties are being used in snack food applications in the United States and Japan, and can also be used to replace wheat flour in some baked products. The lack of gluten may be an advantage in a niche market, targeting people who are gluten intolerant.
Besides feed and food applications, sorghum is used in several other products. Archer Daniels Midland produces wallboard for the housing industry using sorghum. Due to its lack of conductivity, sorghum is becoming a popular material for biodegradable packaging materials. In industrial applications, sorghum is increasingly being used in ethanol production. Currently around 10 percent of the U.S. sorghum crop is consumed by ethanol production. Ethanol can be produced from various crops including corn, wheat and sorghum.
Corn is used most often in ethanol production and sorghum is second. Eight plants in the United States use sorghum to produce ethanol. Five of these plants are located in Kansas. Since Kansas is continuously a top producer of sorghum, this crop is a reliable source for ethanol production. The number of acres planted to sorghum has gradually declined over time, primarily because dryland corn varieties and other crops have been substituted for sorghum.
Production
U.S. grain sorghum production in 2007 was 505 million bushels, up 82 percent from last year. With prices that year averaging $6.95 per cwt, the value of the grain sorghum crop reached nearly $2 billion. Historically, Kansas and Texas have been the top two sorghum-producing states. Between 1982 and 2004, the two states combined produced, on average, 62 percent of the U.S. sorghum crop. In 2007 Kansas and Texas retained their ranking as leading producers. Kansas produced 212 million bushels valued at $843 million while Texas produced 162 million bushels valued at $611 million. Other states producing large quantities of grain sorghum include Nebraska, Louisiana and Arkansas.
Prices
Since sorghum is primarily used as a livestock feed in the United States, and it does not perform as well as corn (that is, higher feed/gain and lower average daily gain) in this capacity, its price will be lower. Sorghum breeding research has focused on improving the agronomic qualities of sorghum while neglecting the feed value of the grain. Research to address these issues is currently in its beginning stages.
Exports and Imports
The United States is the leading exporter of sorghum. In recent years, the country has accounted for more than 80 percent of world trade. Argentina is the world's second largest exporter. The global sorghum trade revolves around U.S. exports to Mexico and Japan. In most years, Mexico has been the world's top sorghum importer. In 2007, however, the European Union temporarily became the world's largest importer of sorghum, which was substituted for corn.
Research and Development
Sorghum breeding research currently focuses on increasing yield potential. Many research areas fall under this category. Insect and disease resistance are two important topics. Insects continually adapt to new crop varieties. So, varieties that were once resistant to certain insects lose that resistance over time. Increasing sorghum’s drought tolerance is also an important issue to increase yields. Sorghum is often grown without irrigation in areas that are susceptible to drought. While the crop can survive in these conditions, a higher tolerance to drought would increase yields. Finally, increasing the grain fill duration would allow greater yields due to time to produce larger berries. The focus of these studies has been lengthening the grain fill duration, shortening the vegetative growth stage to maintain the same total life cycle timing. Sorghum biotechnology research is also in its beginning stages at a few places in the country.
Much of the feed milling and livestock feeding research considers how different milling and feed preparation techniques influence feed use and digestion in livestock. While corn and sorghum have similar chemical makeups, corn is easier for livestock to digest and use than is sorghum. However, certain processing techniques can break down the sorghum seed enough so that it is as easy for livestock to use as corn is. Many studies have compared different processing techniques’ effect on various livestock’s ability to digest and use the feed. Studies on cattle show that steam-flaked sorghum was preferable to dry-rolled sorghum because it improved daily gain and feed efficiency. Research also suggested a complementary effect between corn and sorghum in cattle feeding. Widely used processing techniques for hog feed are hammer milling and roller milling. When these two processes were compared, the study found that feed efficiency was better when hammer-milled feed was used. Also, sorghum was shown to be a slightly more efficient feed than corn (for hogs) when similar particle sizes and milling techniques were compared.
Sources
Agricultural Baseline Projections: Global Agricultural Trade, ERS, USDA.
Grain sorghum production data, Crop Production 2007 summary, NASS, USDA, 2008.
Hamman, L., K. Dhuyvetter, and M. Boland, Economic Issues with Grain Sorghum, Kansas State University, 2001.
Sorghum for Ethanol Production, National Grain Sorghum Producers.
Profile originally created September 2004 and reviewed August 2008.