Crop Production and Management
Crop production and management tests crop geometry, seed-rate calculation, cropping systems, and input scheduling for field crops. Rajasthan conditions-low rainfall, sandy soils, and crops such as bajra, wheat, mustard, and gram-make moisture and stand establishment central.
Core rules
- Cropping systems: mixed cropping grows two or more crops together without row arrangement; intercropping uses definite rows; sequence cropping follows one crop after another; relay cropping sows the next crop before harvest of the previous.
- Crop rotation breaks pest cycles and legumes add nitrogen, but the benefit to the next crop depends on residue and nodulation.
- Tillage prepares seedbed, controls weeds, and manages residue; excessive tillage loses moisture and organic matter.
- Seed rate depends on recommended plant population, test weight, germination %, purity %, and expected field survival. Sowing depth must be shallow enough for emergence; spacing determines plant population.
- Irrigation scheduling depends on critical stages; fertilizer is placed to reduce volatilization and fixation; weeds compete most in early growth.
Worked example
A crop recommendation is 100 kg seed/ha at 100% germination and purity. The lot has 85% germination and 98% purity. Seed rate = 100 ÷ (0.85 × 0.98) = 100 ÷ 0.833 = 120 kg/ha. Reasoning: lower germination and purity mean more seed must be sown to establish the same plant population; divide by the product of the quality fractions, not subtract their sum.
Traps
Confusing mixed cropping with intercropping; using germination alone and forgetting purity; multiplying by quality fractions instead of dividing; sowing too deep in light soils; assuming legume rotation supplies all nitrogen immediately; ignoring critical irrigation stages.