Crop Production and Agronomy
Seasons and cropping systems
Tamil Nadu's cropping seasons include Sornavari (April–May), Kar (June–September), Puratasi (September–October), Navarai (December–January) and Thai pattam (January–February). Common systems are rice–rice, rice–pulses, cotton–rice and groundnut–rice, along with intercropping and mixed cropping. The exam tests package-of-practices, seed rate, spacing, nutrition, water and weed management.
Agronomic practices
- Land preparation, seed selection, nursery raising and transplanting.
- Nutrient management: apply the recommended NPK, with basal and split top dressings; use biofertilizers.
- Water management: irrigate at critical stages, such as panicle initiation in rice and flowering and pegging in groundnut.
- Weed management: cultural, mechanical and chemical methods, including pre-emergence and post-emergence herbicides.
- Follow the TNAU crop production guide for variety and season-specific recommendations.
Worked example
A rice recommendation is 150:50:50 kg N:P₂O₅:K₂O per hectare. Urea contains 46% N, so urea needed = 150 ÷ 0.46 = 326 kg. Single superphosphate contains 16% P₂O₅, so SSP = 50 ÷ 0.16 = 312.5 kg. Muriate of potash contains 60% K₂O, so MOP = 50 ÷ 0.60 = 83.3 kg. The reasoning is to divide each nutrient dose by the fertilizer grade. Apply nitrogen in three splits: basal, tillering and panicle initiation.
Traps that cost marks
Treating the fertilizer grade as the nutrient percentage; forgetting that phosphorus and potassium are expressed as oxides; applying all nitrogen at sowing; and confusing direct-sown and transplanted seed rates.