Climatic Requirements
-
Sorghum thrives in areas with rainfall between 300 and 900 mm annually.
Soil Requirements
-
Higher yields are achieved on sandy loamy soils or deep, well-drained soils.
-
The ideal soil pH ranges between 5.0 and 6.5.
Maturity
-
Early maturity varieties: 110 days
-
Late maturity varieties: 230 days
Planting
-
Spacing: 75 x 5 cm
-
Seeding Rate: 5-7 kg/ha for small seeds and up to 10 kg/ha for large seeds.
-
Planting Time: From the end of November to the end of December in Zimbabwe.
Sorghum should not be continuously planted due to pest build-up. Sow seeds at the onset of the long rains.
-
Planting Method: Drill seeds along furrows (trenches). Plant seeds 3 cm deep when dry planting to prevent germination from false rains, but reduce depth to 2 cm if the ground is wet.
-
Manure Application
-
Apply well-composted manure during land preparation and work it into the soil.
-
Organic foliar feeds can be applied when the plant reaches knee height.
Weed Management
-
Sorghum is very sensitive to weed competition, particularly in the early stages of growth and establishment.
-
Typically, 2-3 hoe-weeding sessions are required.
-
Pre-emergence herbicides like atrazine are recommended for soils with greater than 25% clay content.
Thinning
-
Thinning should be done to maintain an in-row spacing of 15-20 cm. This process should be carried out 4 weeks after emergence before tillering begins.
-
At the same stage, fill gaps caused by poor germination or diseased seedlings.
Disease and Pest Management
-
Aphids: Use malathion, dimethoate (rogor), or diazinon.
-
Spider Mites: Control with acaricides.
-
Stalk Borer: Apply endosulfan, carbaryl, thionex, or carbofuran.
-
Birds: Scaring remains the most effective solution.
-
Downey Mildew: Use metaloxyl, deep ploughing, or resistant varieties.
-
Grain Moulds: Adjust sowing dates to minimize risk.
-
Smut: Spray with fungicides, use resistant varieties, and remove smutted heads.
Harvesting
-
Sorghum yields can reach up to 6 tonnes per hectare.
-
For Seed Production: Harvest sorghum at full maturity.
-
For Animal Feed: Harvest while green and fresh. Allow the crop to wilt for 12 hours in the sun, chop, and feed animals.
-
For Silage: Harvest at the dough stage (between milky and hardening stage).
-
For Dual-Purpose Sorghum: Cut heads manually with a knife or use a combine harvester.
With the right management practices, sorghum can serve as a resilient and versatile crop for food, feed, and silage production. Proper planting, weed control, and disease management are key to maximizing yields and ensuring a successful harvest.