Sorghum (Sorghum bicolor)

General Information:

• Family: Poaceae
• Chromosome Number (2n): 20
• Origin: Africa
• Scientific Name: Sorghum bicolor

Importance and Ranking:

• Sorghum is one of the most important cereal crops in India, ranking second in area after rice and third in production after rice and wheat.
• It is primarily cultivated in marginal lands that are unsuitable for wheat and maize, contributing to low average yields of around 864 kg/ha.

Global Significance: Sorghum is a major food crop worldwide, along with rice, wheat, and maize, and is consumed by millions of people, particularly in Africa and Asia.

Uses of Sorghum: Sorghum has multiple uses in both human and animal consumption:

Human Food:

• Jowar Flour: Used to make flatbreads like roti.
• Sweet Sorghum: Consumed as syrup and in bakery products.
• Pop Sorghum: A popular snack, especially among children.
• Vani Jowar: A specialty from South Gujarat, typically eaten in its green state.

Animal Feed:

• Sorghum is a major feed crop for livestock, including cattle, poultry, and swine.
• Fodder: Used as green fodder, hay, or silage.

Industrial Use:

• Used in breweries for alcohol production and malting.
• Sweet Sorghum: Primarily used in syrup extraction.

Other Uses:

• Stubbles from harvested plants are used as fuel.
• Tribal Consumption: Some tribes rely on sorghum grains and stems for food, with the stems having about 10% sugar content.

Toxicity in Sorghum: Cyanide (HCN): Sorghum varieties, including Sudan grass, produce cyanide in toxic quantities, especially in seedlings. The cyanide levels reduce as the plant matures.

Geographic Distribution:

• Global Cultivation: Sorghum is grown worldwide, except in the cooler regions of northeastern Europe.
• In India: It is primarily cultivated in the central and peninsular regions. States like Madhya Pradesh, Maharashtra, Rajasthan, and Uttar Pradesh are major producers.
• Sorghum Belts: Typically found in regions with 400-1000 mm of rainfall annually.

Climate:

• Sorghum is a hardy crop that thrives in diverse climates:
  • Temperature Range: Tolerates temperatures between 15.5°C to 40.5°C.
  • Rainfall: Requires 35-150 cm of rainfall annually.
  • Altitude: Grown in plateau regions of South India up to 1000 m elevation.
  • Photoperiod: It is a short-day plant, requiring shorter days for flowering and grain formation.

Soils and Field Preparation:

• Soil Types: Sorghum grows best in heavy black soils and clay loams, though it performs poorly in gravelly and marshy soils.
• Field Preparation:
  • In black cotton soil areas, ploughing followed by harrowing is practiced.
  • Cattle manure, about 12 t/ha, is often applied and mixed with the soil.
  • The field is then harrowed multiple times to achieve good tilth.

Verities Popular sorghum varieties include:

Grain Sorghum

• CSH 16, CSH 25, CSV 15: High-yielding hybrids for grains.
• M 35-1: Drought-tolerant; suited for dryland farming.
• CSV 17: High grain and fodder yield; pest-resistant.

Fodder Sorghum SSG 59-3, Pusa Chari 23, CO (FS) 29: High biomass and quality fodder.

Dual-Purpose Sorghum CSH 13, CSV 23: Suitable for both grain and fodder production.

 Seed Rate:

• Broadcasting: 12-18 kg/ha (depending on soil type).
• Drilling: 8-12 kg/ha for well-prepared soils, lower for heavier soils.
• Dibbling: 6 kg/ha.
• Transplanting: Uses nursery-grown seedlings.

Spacing: The typical spacing for sorghum is 45 cm between rows and 15-20 cm between plants, adjusted according to the method of sowing.

Seed Sowing Methods:

1. Broadcasting: Seeds are scattered over the soil, though this is not common due to high seed rate and uneven distribution.
2. Drilling: Seeds are sown using seed drills and covered with soil. The seed rate is typically 8-12 kg/ha.
3. Dibbling: Seeds are placed in furrows by hand, with a seed rate of around 6 kg/ha.
4. Transplanting: Used mostly for hybrid varieties in regions with sufficient rainfall.
5. Ratooning: A process of growing a new crop from the stubble of the previous crop, typically in irrigated conditions.

Manures and Fertilizers:

• Nutrient Requirements:
  • Nitrogen (N): Crucial for higher grain yield.
  • Phosphorus (P): Enhances nitrogen uptake and grain yield.
  • Potassium (K): Response is rare, and it’s applied only if there is a known deficiency.
• Fertilizer Recommendations:
  • Rainfed Sorghum: Apply 25 kg N + 25 kg P₂O₅/ha.
  • Irrigated Sorghum: Apply 40 kg N + 40 kg P₂O₅/ha.
  • High-Yield Varieties: Apply 80 kg N, 40 kg P₂O₅, and 20 kg K₂O/ha.

Water Management:

• Sorghum is primarily rainfed but benefits significantly from irrigation.
• Water Requirement: Around 500-600 mm of water.
• Critical Stages for Irrigation:
  • Germination
  • Knee-high stage (30-35 days after sowing)
  • Flag leaf stage (50-55 DAS)
  • Flowering (70-75 DAS)
  • Grain formation stage (100-105 DAS)
• Irrigation Practices:
  • Light soils require irrigation every 7-10 days.
  • Heavy soils need irrigation every 15-20 days.
  • A pre-sowing irrigation is essential to ensure adequate soil moisture for seedling establishment.

Weed Management:

• Weeds: Common weeds include grasses like Cenchrus spp., Echinochloa crus-galli, and broad-leaved weeds like Amaranthus viridis.
• Control Methods:
  • Mechanical: Intercultivation and hand weeding.
  • Chemical: Use of Atrazine or Propazine pre-emergence and 2,4-D or MSMA post-emergence for broad-leaved and grassy weeds.

Harvesting:

• Harvesting Time: Sorghum is harvested when the grains are hard, and the moisture content is below 25%.
• Harvesting Methods:
  • Plants are either pulled out by hand or cut with sickles.
  • For short crops or mixed cropping, ears are harvested first, followed by stalks.
• Threshing: Threshing can be done by beating dried ears with sticks or using mechanized threshers.

Yield The yield of sorghum varies based on conditions:

• Irrigated, well-managed farms: 3–6 tons/ha.
• Rainfed conditions: 1–2 tons/ha.
• Marginal lands: 0.8–1 ton/ha.
• Fodder yield: 15–25 tons/ha (fresh biomass).

Post-Harvest and Nutrient Management:

• Sorghum is known to deplete significant nutrients from the soil. Crop rotation with legumes, such as pulses, is recommended to restore soil health.
• Toxic Residue: Sorghum may leave residual toxicity in the soil, which can hinder the growth of subsequent crops. Organic practices like green manuring and using FYM (Farmyard Manure) help counter this effect.