Agronomy Module 1

Field Crops & Classification

• Rice is a C3 crop.
• Maize is a C4 crop.
• Sorghum is a drought-tolerant cereal crop.
• Pigeon pea is a short-day legume.
• Soybean is a rainfed legume crop.
• Sugarcane is a tropical C4 crop.
• Cotton is a long-day crop.
• Wheat is a cool-season crop.
• Barley is used as a fodder and food crop.
• Millets are nutritionally rich and drought-tolerant cereals.

Cropping Systems

• Monocropping is growing a single crop in a field continuously.
• Mixed cropping is growing two or more crops simultaneously on the same field.
• Intercropping improves resource use efficiency.
• Relay cropping is sowing the next crop before harvesting the previous one.
• Crop rotation prevents disease and nutrient depletion.
• Rice-wheat system is common in Indo-Gangetic Plains.
• Legume-cereal rotation improves soil fertility through nitrogen fixation.

Soil & Water Management

• Sandy soils have high drainage but low water-holding capacity.
• Clay soils have high nutrient retention but poor aeration.
• Loam soil is ideal for most field crops.
• Irrigation improves yield stability and crop growth.
• Drip irrigation saves water and fertilizer.
• Sprinkler irrigation is suitable for orchards and hilly areas.
• Excessive irrigation causes waterlogging and nutrient loss.
• Mulching reduces soil evaporation and weed growth.
• Green manuring improves organic matter and soil fertility.
• Organic matter improves soil structure and water retention.

Fertilizers & Nutrient Management

• Nitrogen promotes vegetative growth.
• Phosphorus promotes root development and flowering.
• Potassium improves stress tolerance and fruit quality.
• Zinc deficiency causes chlorosis in cereals.
• Boron deficiency leads to hollow stem in cauliflower.
• Sulfur deficiency causes yellowing of young leaves.
• Urea is a common nitrogenous fertilizer.
• SSP (Single Super Phosphate) provides phosphorus and sulfur.
• MOP (Muriate of Potash) provides potassium.
• Biofertilizers like Rhizobium and Azotobacter fix atmospheric nitrogen.

Weed Management

• Weeds compete for nutrients, water, and light.
• Pre-emergence herbicides are applied before crop germination.
• Post-emergence herbicides control weeds after crop emergence.
• Manual weeding is labour-intensive but eco-friendly.
• Cultural methods like mulching and crop rotation help weed control.
• Allelopathic crops suppress weed growth naturally.
• Parthenium hysterophorus is a noxious weed.
• Echinochloa crus-galli is a major weed of rice.
• Herbicides must be applied at recommended doses to avoid crop injury.
• Integrated weed management combines chemical, mechanical, and cultural methods.

Seed & Crop Production

• Certified seeds ensure high germination and disease-free crops.
• Hybrid seeds produce higher yield due to heterosis.
• Seed treatment prevents seed-borne diseases.
• Seed rate depends on crop type, spacing, and seed size.
• Proper plant population increases yield per unit area.
• Sowing time affects flowering and maturity.
• Seed dormancy can be broken by scarification, stratification, or soaking.
• Crop spacing affects light interception and nutrient use efficiency.
• Seed replacement after 3–4 years maintains viability and vigour.
• High-quality seed leads to uniform germination and crop stand.

Crop Physiology & Growth

• Photosynthesis occurs mainly in green leaves.
• Respiration provides energy for growth and development.
• Transpiration helps in cooling and nutrient transport.
• Vegetative growth precedes reproductive growth in crops.
• Flower initiation is influenced by photoperiod and temperature.
• Crop maturity depends on genetic and environmental factors.
• Tuberization in potato is influenced by temperature and day length.
• Flowering in wheat is induced by vernalization.
• Lodging in cereals is caused by high nitrogen and wind.
• Crop yield is the product of growth rate, harvest index, and biomass.