SORGHUM (Sorghum bicolor) Cultivation Notes BSc Agriculture

AGRON – 211 Crop Production Technology – I (Kharif Crops)]

• SORGHUM – Sorghum bicolor
• Family – Poaceae
• 2n- 20
• Origin place – Africa

Sorghum

• Importance: Most important cereal crop in India.
• Ranking: Second in area (after rice) and third in production (after rice and wheat).
• Cultivation: Grown in both kharif and rabi seasons, contributing to low average yields (864 kg/ha).
• Growing Conditions: Primarily cultivated in marginal lands unsuitable for wheat and maize.
• Global Significance: Major food crop worldwide, alongside wheat, rice, and maize.
• Dependency: Millions in Africa and Asia rely on sorghum as a staple food.

Uses of Sorghum

1. Human Food and Animal Feed: Jowar is consumed by both humans and animals.
2. Fodder: Used as fodder for livestock.
3. Chopped Green Stems: Prepared as hay or silage; also used as pasture.
4. Sweet and Pop Sorghum: Eaten directly by humans.
5. Jowar Flour: Used to make roti.
6. Breweries: Utilized for alcohol production and malting.
7. Jowar Cake: Made from fermented dough.
8. Sweet Sorghum: Used for syrups and in bakery products.
9. Stubbles: Leftover stubbles serve as fuel.
10. Tribal Consumption: Tribals consume sorghum grains and sweet stems (10% sugar content).
11. Vani Jowar: A specialty from South Gujarat, eaten in green perched conditions.
12. Jowar Dhani: Pop sorghum popular among children.
13. Animal Feed: Grain fed to cattle, poultry, and swine, in addition to human consumption.

CYANIDE( HCN) : Sorghum varieties and sudan grass produce toxic quantity of cyanide. The cyanide
concentration is highest in seedling stage and declines as the plant grows.

Geographic Distribution of Sorghum

• Global Cultivation: Grown worldwide except in the cool northeastern parts of Europe.
• Sorghum Belts in India: Receive 400-1000 mm of rainfall.
• Major Regions:
  • Africa: Nigeria and Sudan are leading producers.
  • North America: Significant cultivation.
  • South America and Asia: Also grow sorghum.
• India: Primarily cultivated in central and peninsular regions.

Climate

• Sturdiness: Can withstand varied climatic conditions better than most crops.
• Cultivation Areas: Grown successfully in:
• Arid regions of Uttar Pradesh and Rajasthan.
• Humid areas of West Bengal and Bihar.
• Climate: Primarily a tropical warm weather crop.
• Temperature Range: Tolerates temperatures from 15.5 °C to 40.5 °C.
• Rainfall: Thrives with annual rainfall variations of 35-150 cm.
• Elevation: Grows in the plateau region of South India up to 1000 m elevation.
• Photoperiod: A short day plant; flowering and grain formation occur as day length shortens in winter.

Soils and Field Preparation for Sorghum

• Soil Types:
• Grows well in heavy black soils and clay loams.
• Poor performance in gravelly and marshy soils.
• Field Preparation:
• Sorghum is often grown under low input conditions, making soil management crucial for increasing yields.
• Preparation is not as thorough as for other cereals; however, good tilth is essential.
• Land Preparation Steps:

1. Ploughing: In black cotton soil areas, ploughing followed by harrowing is practiced if weeds are present.
2. Equipment: Use iron or country ploughs; tractor discing or ploughing is advisable.
3. Cattle Manure: Apply 12 t/ha and mix with soil through ploughing or harrowing.
4. Blade Harrowing: Work land with a blade harrow 2-3 times; sometimes use a gorru without seeding attachment.

Seeds and Sowing Methods

Sorghum can be sown using several methods:

1. Broadcasting:

• Description: Seeds are scattered over the soil; not widely used due to high seed rate and uneven distribution.
• Seed Rate: 12-18 kg/ha (less for dry lands).
• Usage: Typically for irrigated lands with beds and channels.

2.Drilling:

• Description: Seeds are sown using seed drills and covered with soil.
• Seed Rate: 8-12 kg/ha; higher for light soils, lower for black soils.
• Spacing: 45×15-20 cm at 3-4 cm depth.

3.Dibbling:

• Description: Seeds are placed in furrows, requiring more labor but using less seed (6 kg/ha).
• Spacing: 45×15 cm; depth of 2.5-5 cm.
• Practice: Common in dry lands; thinning done at 15-20 days after sowing.

4.Transplanting:

• Description: Seedlings from nurseries are planted in furrows.
• Usage: Common in regions with sufficient rainfall; used for hybrid sorghum.
• Benefits: Ensures better establishment; practiced mainly in South India.

5. Ratooning:

• Description: Cultivating a new crop from stubble of the previous crop, avoiding reseeding.
• Suitability: Effective under irrigated conditions; hybrids like CSH-1 are best for ratooning.
• Steps:
  1. Harvest main crop while leaving 4-6 inches of stubble.
  2. Irrigate 2 days after harvesting to promote sprouting.
  3. Apply 60 kg N/ha in two splits (basal and 30 days post ratooning).
  4. Thin weak sprouts, leaving 2-3 healthy ones per stubble.
  5. Maintain moisture from boot leaf to grain hardening stage.
  6. Ratoon crop ready for harvest in 80-85 days.
  7. Implement plant protection measures as needed.
• Ratooning Advantages: Reduces costs for land preparation and sowing, increases net income when managed well.

Spacing for sorghum: 45×12-15cm
Seed treatment: For control of grain smut disease – treat the seed with sulphur @ 5g/kg seed.
OR With organo mercurial compounds or carbomates @ 2.5g/kg seed. For shoot fly-carbofuran 50 WP@100g/kg seed.

Manures and Fertilizers for Sorghum

Nutrient Requirements:

• Nitrogen (N): Essential for increasing grain yields. Its uptake enhances phosphorus (P) absorption.
• Phosphorus (P): Particularly effective when applied with nitrogen. Increases grain yield significantly.
• Potassium (K): Response to K is infrequent; only apply if there is a known deficiency.

Recommended Fertilizer Doses:

• Rainfed Varieties:
• 25 kg N + 25 kg P₂O₅/ha often yields better results than 50 kg N/ha.
• Irrigated Conditions:
• Apply 40 kg N and 40 kg P₂O₅/ha.
• General Dose for High-Yield Varieties (HYVs):
• 80 kg N, 40 kg P₂O₅, and 20 kg K₂O/ha.

Time and Method of Application

• Fertilizer Application:
• Avoid direct contact with seeds to prevent germination injury.
• Drill fertilizers into the soil before sowing, at a depth of 5 cm below the seed level for optimal uptake.
• Heavy Soils:
• Apply all N and P₂O₅ basally or drill them 2 inches away and 2 inches below the seed at sowing.
• Light Soils:
• Split N application into two: half as basal and the other half at 30-35 days after sowing (around the knee-high stage).

Water Management for Sorghum (Jowar)

General Overview:

• Jowar is primarily a rainfed crop but benefits significantly from irrigation.
• It has a deep and extensive fibrous root system, which aids in drought resistance.
• Total water requirement: 500-600 mm, with 6-9 irrigations of 5-6 cm depth each.

Critical Stages for Irrigation

Irrigation is crucial at the following growth stages:

1. Germination (at sowing)
2. Knee High Stage (30-35 days after sowing, DAS)
3. Flag Leaf Stage (50-55 DAS)
4. Flowering (70-75 DAS)
5. Grain Formation Stage (100-105 DAS)

Time of Irrigation

• Irrigation is optimal when Available Soil Moisture (ASM) is depleted to 50-60% in the effective root zone. Irrigating at this moisture level has shown to yield the best results.
• Avoid excessive irrigation during seedling stage as it can lower soil temperature and leach nutrients.

Peak Water Needs

• Peak water requirements occur during:
• Booting to Seed Setting Stage (around 25th, 45th, and 55th DAS).
• These correspond to critical growth stages: PI, boot leaf, and flowering.

Irrigation Frequency

• For irrigated crops:
• Light soils: Irrigate once every 7-10 days.
• Heavy soils: Irrigate once every 15-20 days.

Specific Irrigation Practices

• A pre-sowing irrigation to bring the top 120 cm of soil to field capacity is essential.
• An irrigation 15 days after emergence is critical for shallow soils.
• Aim to bring 90 cm of soil to field capacity during irrigation.

Weed Management

Important Weeds Associated with Sorghum

• Grasses: Cenchrus spp., Digitalis sanguinalis, Echinochloa crus-galli, Eleusine indica
• Sedges: Cyperus rotundus
• Broad-Leaved Weeds: Amaranthus viridis, Celosia argentea, Commelina bengalensis, Striga lutea

• Mechanical:
• Rainfed Crops: Intercultivation with danthi; starts at 15-20 DAS, repeated every 10 days.
• Irrigated Crops: Hand weeding by 20 DAS; light ploughing when crop is 30-38 cm tall.
• Chemical:
• Pre-Emergence: Atrazine/Propazine (0.25-0.50 kg a.i./ha in 900 liters of water).
• Post-Emergence:
  • MSMA (2 liters/ha in 700 liters of water) for nut grass.
  • 2,4-D (0.75-1.0 kg a.i./ha) for broad-leaved weeds.

Striga Control

• Common Species: Striga asiatica, Striga lutea, Striga densiflora, Striga euphrasiodes, Striga hermonthica.
• Control Measures:
• Remove before flowering.
• Chemical: Methaxone or 2,4-D (0.2% solution).
• Deep ploughing, double nitrogen dose, resistant varieties (SPV-462, N-13).
• Catch crops (cotton, groundnut).
• Methyl bromide (200 kg/ha) as a fumigant (costly).
• 2,4-D post-emergence (0.75-1.0 kg a.i./ha) for moderate control.

Harvesting and Threshing of Sorghum

• Harvesting Time:
• Harvest when grains are hard and moisture is <25%.
• Irrigated crops mature later than dry crops.
• Harvesting Method:
• Pull plants out with roots or cut at the base with sickles.
• For short crops or mixed cropping, harvest ears first and cut stalks later.
• Post-Harvest Process:
• Allow harvested plants to dry in the field for 3-4 days.
• Remove ears and stack straw for a week for complete drying before carting.
• Fodder Harvesting:
• Harvest at or before 50% flowering to avoid high hydrocyanic acid (HCN) content.
• Multi-Cut Varieties:
• First Cutting: 2 months after sowing.
• Subsequent Cuts: 30-40 days after the first cut.
• Threshing Methods:
• Beat dried ears with sticks or trample with cattle.
• Use stone rollers; threshing machines are also available.
• Winnow, clean, and dry grain to 12-13% moisture.

Sorghum’s Nutrient Effect

• Sorghum removes significant nutrients from the soil; avoid following with another exhaustive crop like cotton.
• Follow with pulse crops for better soil health.
• Toxic Residue:
• Some succeeding crops may struggle due to residual toxicity from sorghum.
• Counteract with good manuring (FYM), green manuring (indigo/wild indigo), or crop rotation.

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