Sorghum can grow in a wide range of ecological conditions and can still yield well even under unfavorable conditions of drought stress and high temperatures.
It is generally grown between 40oNorth and 40o South of the equator, in warm and hot countries characteristic of the semi-arid environment.
Sorghum requires warm conditions but it can be grown under a wide range of conditions. It is also widely grown in temperate regions and at altitudes of up to 2300 m in the tropics.It can tolerate high temperature throughout its life cycle better than any other crop.
Sorghum requires about 26-30oC temperature for good growth. The minimum temperature for the germination of the sorghum seed is 7 to 10oC.
Grain sorghum does not germinate and grow well under cool soil conditions. Poor emergence and seedling growth may result if planted before soil temperatures reach 35oC. Sorghum is best adapted to areas having an average annual rainfall between 45 to 65 cm (17 to 25 inches).
Although sorghum can respond to good moisture supplies, it is nevertheless one of the toughest, drought
tolerant crops available and this tends to maintain its popularity in the regions where the weather is very unpredictable.
Note: Red dots indicate sorghum growing environment
The ability of sorghum to grow in drier environments is due to a number of physiological and morphological characteristics;
- Produces many roots compared to other cereals,
- Has reduced leaf area thus reducing water loss through transpiration,
- Can remain dormant during drought and resume growth when conditions are favorable,
- Above ground parts of plant grow only after the root system is well established,
- The leaves have a waxy coating and have the ability to roll in during drought thus effectively reducing transpiration,
- Competes favorably with most weeds.