Detailed Cultivation of Soybean

Soybean (Glycine max) is a high-value leguminous crop grown for its edible seeds, oil, and various other industrial uses. It is also an important source of protein for human consumption and animal feed. Below is a comprehensive guide to soybean cultivation.

Scientific Classification

• Kingdom: Plantae
• Division: Angiosperms
• Class: Eudicots
• Order: Fabales
• Family: Fabaceae
• Genus: Glycine
• Species: G. max

Importance and Uses

• Edible Products: Soybeans are a rich source of plant-based protein (around 40%) and vegetable oil (about 20%). They are consumed in various forms, including:
  • Soy Milk, Tofu, Soy Sauce, Tempeh
  • Soybean oil is used in cooking, frying, and food processing.
• Animal Feed: Soybean meal, produced after oil extraction, is an excellent source of protein used in livestock feed.
• Industrial Uses:
  • Biodiesel: Soybean oil is used to make biodiesel.
  • Cosmetics: Used in soaps, lotions, and other personal care products.
  • Pharmaceuticals: Utilized in some medications, supplements, and formulations.
• Health Benefits: Rich in essential fatty acids, fiber, vitamins (B-complex, Vitamin E), and minerals (iron, calcium), soy is considered a heart-healthy food that helps in managing cholesterol levels and provides a good alternative to meat for vegetarians and vegans.

Origin and History

• Origin: Soybean is native to Eastern Asia, specifically to parts of China. It was domesticated around 2000 BC and later spread to Japan, Korea, and the USSR.
• Introduction to Other Countries: Soybean was introduced to the United States in 1908 and to India in the 20th century, with significant work started in PUSA (Bihar) and later in Pantnagar and Jabalpur by Edwin Bay in 1963-1964.

Importance of Soybean

• Rich in Protein and Oil: Soybean is a rich source of vegetable protein (about 40%) and vegetable oil (about 20%).
• Versatile Uses:
  • Soy-based food products such as milk, curd, ice cream, and candy.
  • Soy oil is used for various industrial purposes like soap, glycerin, varnish, and biodiesel.
  • Soymeal is an excellent livestock feed, rich in protein.

Area and Production

Global Distribution:

• USA: Leading producer with 28.7 million hectares under soybean cultivation, producing 75 million tonnes, with a yield of 2.6 t/ha.
• Brazil: Second largest producer, covering 13.3 million hectares and producing 31.4 million tonnes (yield: 2.3 t/ha).
• China: Produces 13.6 million tonnes from 8.2 million hectares (yield: 1.7 t/ha).
• India: Grows soybeans on 5.8 million hectares, producing 6.5 million tonnes with a yield of 1.1 t/ha.

Soybean in India:

• States with Major Soybean Cultivation:
  • Madhya Pradesh (MP): 4.26 million hectares, production of 4.92 million tonnes (yield: 1.15 t/ha).
  • Maharashtra: 0.86 million hectares, production of 0.85 million tonnes (yield: 0.99 t/ha).
  • Rajasthan: 0.50 million hectares, production of 0.63 million tonnes (yield: 1.27 t/ha).
  • Other states like Karnataka and Uttar Pradesh also contribute, though in smaller amounts.

Climate Requirements

Soybean is a short-day plant but is sensitive to day length and temperature.

• Temperature:
  • Minimum: 5°C
  • Optimum: 30°C
  • Maximum: 40°C (temperatures above this can damage the crop).
• Light Intensity: Soybean requires a minimum of 1076 lux light for 2 consecutive days to initiate flowering.
• Rainfall: Soybean requires 640-750 mm of water for optimal growth. Timely rainfall during key growth stages is crucial.
• Soil Requirements: Soybean thrives in well-drained soils such as Alfisols, Vertisols, Inceptisols, and Mollisols. Soil pH should be between 6.0-7.5 for optimal growth.

Land Preparation

• Seedbed Preparation: A fine seedbed is crucial for proper seed germination.
• Ploughing: The field should be ploughed to a fine tilth to allow good seed-soil contact.
• Leveling: The field should be leveled to ensure uniform irrigation and to avoid water stagnation.

Sowing

• Time of Sowing: In India, soybean is typically sown in the Kharif season (June to July), although Rabi sowing is also practiced in some areas.
• Seed Rate: Typically, 75-80 kg of seed per hectare is used, depending on seed size and variety.
• Spacing:
  • Kharif: 45 cm x 4-5 cm between rows and plants.
  • Rabi: 30 cm x 2-3 cm.
• Depth of Sowing: Seeds are planted at a depth of 2-5 cm.

Nutrient Management

Soybean is a leguminous plant and can fix nitrogen in the soil through its symbiotic relationship with the bacterium Bradyrhizobium japonicum. However, additional fertilizers are required for optimal growth.

• Nutrient Removal by Soybean (for 4-tonne crop):
  • 370 kg N, 40 kg P, 130 kg K, 90 kg Ca, 40 kg Mg, 28 kg S.
• Fertilizer Recommendation:
  • 20:80:40:40 (N:P:K:S kg per hectare).
  • For soils with zinc deficiency, especially in high rainfall areas, apply 5 kg ZnSO4 as basal fertilizer.

Irrigation Management

• Soybean requires 640-750 mm of water throughout its growing period.
• Critical Stages for Irrigation:
  • Sprouting, flowering, pod initiation, and grain filling.
• Over-irrigation can lead to root diseases, so careful management is essential.

Weed Management

• Weed Control: Soybean is sensitive to early weed competition. Weed infestation can reduce yields by up to 54-65%.
• Integrated Weed Management (IWM): A combination of manual weeding, mechanical weeding, and selective herbicides is recommended.
• Pre-emergence herbicides like pendimethalin or metribuzin are commonly used.

Pest and Disease Management

• Pests:
  • Soybean Pod Borer: Can damage pods and seeds.
  • Root-Knot Nematodes: Can affect root health.
  • Leafhoppers and Aphids: May cause damage to leaves and pods.
• Diseases:
  • Rust: Fungal disease that affects the leaves.
  • Alternaria Blight: A fungal infection that causes leaf lesions.
  • Fusarium Wilt: A soil-borne disease that affects the root system.

Management: Use of resistant varieties, crop rotation, and application of appropriate fungicides or insecticides when necessary.

Harvesting and Post-Harvest Management

• Maturity Indicators: Soybean is ready for harvest when:
  • Leaves turn yellow and start to shed.
  • Pods turn brown and dry.
  • Moisture content: When the seed moisture reaches around 13-14%.
• Harvesting Method:
  • Manual: In small fields, the plants are cut manually.
  • Mechanical: For large fields, mechanical harvesters are used.
• Threshing: The moisture content should be 15-17% for cutting, and 13-14% for threshing.
• Storage: Soybean should be stored at 8-10% moisture content to avoid mold and spoilage. Proper drying and storage are critical.

Yield

• Global Average Yield: Around 2.2 t/ha.
• In India: Soybean yields range from 0.68 to 1.27 t/ha depending on the state and crop management practices.
• Factors such as soil fertility, irrigation, pest management, and timely harvesting play a significant role in determining yield.

Challenges of Soybean Cultivation in India

• Low Yield: Compared to global standards, the yield in India is still low.
• Lack of Infrastructure: Poor market linkages and limited processing industries for soybean.
• Pests and Diseases: Soybean is susceptible to several pests and diseases, which can reduce yield and quality.
• Awareness: Farmers often lack knowledge about modern farming practices and the benefits of soybean cultivation.