Sorghum, production

Sorghum is usually grown as a rain fed crop but it's also grown under irrigation especially in some semiarid parts of India, Sudan and the USA. In traditional cropping systems, sorghum is mostly grown as a mixed crop with other crops such as millet, pigeon peas, groundnut and cowpeas.

Under such cropping systems, the cereal (sorghum/millet) is considered the main crop and is sown at sole crop rate. Management practices are also centered on it. In traditional cropping systems especially in semiarid tropics and sub tropics, sorghum is often sown at the end of the rotation. This is because sorghum often depresses yields of succeeding crops due to reduction in soil moisture and nitrate depletion.

Sorghum grows in a wide range of soils and a firm seedbed is ideal but this rarely achieved under conditions of peasant agriculture. Generally, in semiarid regions, sorghum is planted at the onset of the rains, as any delay can result in significant crop losses.

The spacing is usually 60-90cm x 20-60cm depending on soil fertility and availability of soil moisture. The seed rate for arid and semiarid areas ranges from 2-3 kg/ha. Seed dressing is usually done especially in areas with high prevalence of smuts and seed borne fungal diseases.

In some parts of East Africa, sorghum is dry planted before onset of the rainy season while in West Africa several seeds are planted on hills or ridges and later thinned to about 2-3 seedlings. In countries where mechanized agriculture is practiced, sorghum is planted by drilling seed in rows using planters.

1.1 Fertilizer Application

In traditional cropping systems, sorghum crop is rarely fertilized. This is probably attributed to the fact that sorghum does well even in soils with marginal fertility. However, application of manure or inorganic fertilizer can result in improved yields if there is adequate moisture in the soil. Otherwise, in areas with limiting moisture conditions, response to manure and inorganic fertilizer is poor.

Standard recommendations for manure and inorganic fertilizer vary from region to region and depend on a number of factors. Generally, application of 3 tons/acre of cattle manure and 23 kg/ha of N have been proven to give good results (under rain fed conditions) in a number of countries especially in the semiarid tropics and sub tropics. In order to realize good results, it's recommended that inorganic fertilizer application should be split into two (2) i.e. at planting (basal application) and 1-2 weeks before flowering (top dressing)

Weeding is normally done using a hand or a hand hoe in subsistence semiarid agriculture. Weeding operations in developed countries are mechanized and done by weeders. Weed control is only important in early stages of crop growth since when established, sorghum often out competes weeds.

Most sorghum cultivars mature at 100-110 days after planting (DAP) or less while long-term sorghum varieties take about 180 DAP. On farm yields range from 650-750 kg/ha on average (under rain fed conditions) in semiarid environments. Under irrigation yields of up to 2000 kg/ha are obtainable. In the US, irrigated hybrid sorghum can give yields of up to 8000 kg/ha.

Harvesting is done by cutting the heads from standing plants while in certain communities, it's done by cutting down the whole plant and later cutting off the head when it's fully dry.