Scientific name – Sorghum bicolor
English common name – Sorghum
Asian common names – Burmese: shallu Chinese: 高梁 gao liang Hindi: jowar Japanese: morokoshi, sorugamu Thai: ข้ำ วฟ่ ำง khao fang
Variety – Photo: ECHO Asia staff Pang Daeng
General description and special characteristics – A warm-season, short-day annual grass, sorghum is the fourth most important cereal grain grown in the world. Being a C4 photosynthetic pathway plant, sorghum is at an advantage in areas where low rainfall and high temperatures will not produce a reliable corn crop. Even in dry soils, sorghum manufactures starch efficiently, making it a good energy crop for livestock. It grows best under relatively high temperatures and full sunlight exposure. Sorghum is also able to withstand high rainfall, some waterlogging and salinity. It can also endure drought conditions due to its deep-penetrating root system.
Crop uses (culinary) – In northern Thailand, cleaned grain is cooked like rice or popped like popcorn. Around the world, some types of sorghum are cracked like oats for porridge, some malted for beer, and others baked like wheat into flatbreads. A few types have sugary grains and are boiled in the green stage like sweet corn. The stems of other types are processed to yield sugar and syrup. Sorghum varieties with higher tannin content in the seed heads are more resistant to being eaten by birds but are less palatable to humans. Consumption of sprouted sorghum seeds is not recommended because the cyanide content in sprouts could be fatal when added to a diet high in cassava. Sorghum is higher in protein than maize but lower than wheat. It is a good source of vitamin B.
Crop uses (livestock production) – The whole sorghum plant is often used as forage, hay, or silage. According to Cook et al. (2005), leaves of various types of sorghum can be poisonous to grazing livestock due to hydrogen cyanide (prussic acid), especially in young dark-blue colored re-growth after plants are stressed by drought or heat. Ensure plants are 45-60 cm tall (18-24 in) tall before allowing livestock to graze. Grain is fed to chickens raw or cooked as pig feed.
Other uses – The living plants are used for windbreaks, for cover crops, and for staking yams and other heavy climbers. Sorghum is also used to produce industrial alcohol, liquid fuel for powering vehicles or cooking meals, vegetable oil, adhesives, waxes, dyes, sizing for paper and cloth, and starches for lubricating oil-well drills.
Seasons of production – In northern Thailand, sorghum does best when planted at the beginning of the rainy season. In the tropics, sorghum can be planted at any time during the year when temperatures are 20°-30°C (68°-86°F) and the rains have begun. In the subtropics, the crop is better planted in late summer and early fall.
Length of production and harvest period – Approximately 6 months from seed to harvest.
Production methods – With full seedbed preparation, a 1.5cm – 5 cm (0.6 - 2 in) planting depth is recommended, depending on texture and moisture of soil. Upland farmers in Southeast Asia often intercrop sorghum with upland rice. Assuming adequate moisture, second harvests are reportedly possibly after cutting the first crop and allowing plants to regrow and set seed.
Plant spacing – 60 cm (2 ft) plant spacing is recommended. Higher yields can result from rows planted close together but hills should be spaced far enough apart in the row to cause plants to tiller and produce large heads and grain.
Pollination – Generally self-pollinated but a small amount of crossing may occur between all types and varieties of S. bicolor. Cross-pollination can be controlled by bagging the plant’s tassel as soon as it begins to emerge. Allow bags to remain in place until all of the seeds have formed (Ashworth 1991).
Environmental conditions for production – Sorghum can be grown from sea level to 1,000 m (3,281 ft). Rainfall of 200– 1,250 mm (8-50 in) is preferred.
Soil requirements – Adapted to a wide range of soils if moderately well-drained; prefers a pH of 5.0-8.5.
Pests and diseases – In areas where sorghum would be expected to yield a good crop, weed competition for water and nutrients can limit growth. Where necessary, use varieties that are resistant to drought and Striga (Genus: Striga; Species: lutea, hermonthica and gesnerioides), a parasitic weed. Birds can be a problem when heads are ready for harvest.
Seed saving – To harvest seeds, watch for seed heads to dry. Cut the stalks by hand and allow them to dry in the field or in loose piles under cover (avoid direct sun exposure). Thresh to separate seeds from chaff. Store seed that has less than12- 13% moisture content. To test for low moisture content, several seeds can be hit with a hammer. If the seeds shatter, then they are ready for storage. If the seeds are mashed instead, more drying is needed. Under village conditions, mix dry seeds with sand, wood ashes, dried cow dung, or lime to discourage stored seed pests. Store in a cool, dry location.
References –
Ashworth, S. 1991. Seed to Seed. Decorah, Iowa: Seed Savers Exchange, Inc.
Cook, B. G., B. C. Pengelly, S. D. Brown, J. L. Donnelly, D. A. Eagles, M. A. Franco, J. Hanson, B. F. Mullen, I. J. Partridge, M. Peters, and R. Schultze-Kraft. 2005. Sorghum (annual). Tropical Forages: An Interactive Selection Tool. Available: http://www.tropicalforages.info/key/Forages/Media/Html/Sorghum_(annual).htm.
EPPO. 2012. Data Sheets on Quarantine Pests: Striga spp. European and Mediterranean Plant Protection Organization. Available: http://www.google.com/urlsa=t&rct=j&q=&esrc=s&source =web&cd=1&ved=0CFoQFjAA&u rl=http%3A%2F%2Fwww.eppo.int%2FQUARANTINE %2FPest RiskAnalysis%2FPRAdocs_plants%2Fdraftds%2 F99-7450%2520DS% 2520STRSS.doc%3.
FAO. 2012. Sorghum bicolor (L.) Moench. Grassland Species Profiles. Available:http://www.fao.org/ag/agp/agpc/doc/gbase/DATA/PF000319.HTMNational Research Council.
National Academies. 1996. Lost Crops of Africa: Volume I: Grains. Washington, DC: The National Academies Press.