Sorghum (Sorghum bicolor) is one of the most important food grain crops in the world and a staple food for millions of people. It is consumed as whole grain, parched grain, and popped grain. Sorghum is also a major source of fodder and feed for cattle, poultry, and swine.
Sorghum grain is highly nutritious, containing:
- 10–12% protein
- 3% fat
- About 70% carbohydrates
Due to its drought tolerance, adaptability, and multiple uses, sorghum plays a vital role in food security and livestock farming, especially in semi-arid regions.
Growth Stages of Sorghum Crop
Understanding crop growth stages helps in timely irrigation, fertilization, and pest control.
1. Seedling Stage
- Germination occurs 4–5 days after sowing
- Emergence of coleoptile marks the seedling stage
2. Flag Leaf Stage
- Occurs at 40–45 days after sowing (DAS)
- 3–4 fully expanded leaves are visible
3. Boot Stage
- Ear head remains enclosed in the sheath under the flag leaf
- Occurs at 45–60 DAS
4. Soft Dough (Milky) Stage
- Endosperm contains watery fluid
- Occurs at 70–85 DAS
5. Hard Dough Stage
- About 75% of grain weight accumulated
- Grain content becomes relatively solid
6. Physiological Maturity
- Maximum dry matter accumulation in grain and plant
- Occurs at 85–95 DAS
Climatic Requirements for Sorghum Cultivation
- Sorghum requires a warm climate but adapts to a wide range of conditions
- Grown during summer in temperate regions and year-round in tropics
- Optimum temperature: 26–30°C
- Minimum temperature for germination: 7–10°C
- Yield reduces if mean temperature exceeds 26°C during heading stage
Rainfall Requirement
- Suitable for semi-arid regions
- Annual rainfall range: 350–1000 mm
- Highly drought tolerant; remains dormant during moisture stress
- Can tolerate temporary waterlogging
Soil Requirement for Sorghum
- Grows well in medium to deep soils with good water-holding capacity
- Suitable soil pH range: 5.5–8.5
- Tolerates mild acidity and salinity
- Black cotton soils of central India are ideal for sorghum cultivation
Land Preparation
- Deep ploughing (20–25 cm) after rabi harvest using mould board plough
- Leave soil exposed to sun until onset of monsoon
- Followed by 2–3 harrowings
- Planking is done to break clods and level the field
- Remove crop residues and stubbles
Seed Rate and Spacing
- Varieties: 8–10 kg seed/ha
- Hybrids: 10–12 kg seed/ha
- Sowing depth: 3–4 cm (not more than 5 cm)
Proper spacing ensures better tillering and yield.
Method of Sowing
- Sowing can be done by:
- Broadcasting, or
- Drilling seeds behind the plough
- Row sowing is recommended for hybrids and varieties
- Sowing should be done in sunrise–sunset direction to minimize shading
Seed Treatment
- Treat seeds with:
- Thiram or Agrosan G.N. @ 3 g/kg seed
- Protects against fungal diseases like grain smut
- Always use certified and treated seeds from reliable sources
Manure and Fertilizer Management
Sorghum is an exhaustive crop and rapidly depletes soil nutrients.
Organic Manure
- Apply 10–15 tonnes FYM or compost per hectare before last harrowing
- Improves water-holding capacity and soil microbial activity
Fertilizer Application
- Fertilizer dose depends on:
- Variety (local or hybrid)
- Rain-fed or irrigated condition
- Apply fertilizers 3–4 cm beside and below the seed
- Apply half nitrogen at sowing and remaining half:
- At 30–35 DAS or knee-height stage
Nutrient Uptake Pattern
- Nitrogen uptake highest at soft dough stage
- Phosphorus uptake continues until grain filling
- Potassium uptake is higher in early stages
Micronutrients
- Iron deficiency: common in calcareous soils
- Zinc deficiency: apply 25–50 kg zinc sulphate/ha at sowing
Thinning
- Maintain optimum plant population
- First thinning: 10–15 days after emergence
- Second thinning: 20–25 DAS
Weed Management in Sorghum
- Critical period: 15–35 DAS
- Yield loss due to weeds: 20–60%
- Common weeds:
- Echinochloa crusgalli
- Setaria glauca
- Cynodon dactylon
- Eleusine indica
- Phragmites karka
Weed Control Measures
- Manual hoeing and weeding
- Pre-emergence herbicides:
- Atrazine @ 0.5–1.0 kg a.i./ha
- Propazine @ 1.0–1.5 kg/ha
- Post-emergence herbicides:
- Trifluralin @ 0.8–1.2 kg/ha
- Halosulfuron @ 30–40 g/ha
- Effective control of Striga using simazine or propazine
Irrigation Management
- Sorghum is drought tolerant but sensitive to waterlogging
- Critical stages for irrigation:
- Knee-height
- Flowering
- Grain filling
- Kharif crop generally does not need irrigation
- Provide protective irrigation during long dry spells
- Ensure proper drainage
- Optimum irrigation schedule:
- 50% DASM or IW/CPE ratio of 0.6
Cropping Systems in Sorghum
- Mainly grown as kharif crop
- Intercropping preferred under moisture stress
Popular Intercropping Systems
- Sorghum – wheat – mung
- Sorghum – pea
- Sorghum – gram
- Sorghum – potato – wheat
- Sorghum – cotton
- Sorghum – tobacco
- Sorghum – ragi – groundnut
- Sorghum – sorghum (rabi)
Paired row planting (30/60 cm or 30/90 cm) gives higher returns.
CSH-6 is the best variety for intercropping.
Harvesting and Threshing
- Crop duration: 100–115 days
- Harvest when grain moisture is 15–20%
- Do not wait for stalks to dry completely
- Ear heads dried to 12% moisture
- Threshing done using:
- Threshers
- Beating with sticks
- Trampling by bullocks
Yield of Sorghum
- Rain-fed crop:
- Grain: 25–30 q/ha
- Dry stover: 80–100 q/ha
- Irrigated crop:
- Grain: up to 50 q/ha
- Stover: 100–125 q/ha