Crops: Establishment, Nutrition, Protection and Harvesting
Domain focus
Crops tests establishment, nutrition, protection and harvesting decisions across tillage and grassland crops, including calculations and integrated management.
Core rules
- A fine, firm seedbed with adequate moisture and temperature supports germination; sowing depth and seed rate must suit the crop and seed size.
- Rotation, variety choice, soil testing and balanced N, P, K and lime use reduce pest, disease and nutrient problems.
- Integrated pest management uses monitoring, thresholds, cultural control and targeted pesticides; resistance management matters.
- Harvest at correct maturity and moisture; dry and store to prevent mould and quality loss.
- Check seedbed moisture before sowing and avoid working soil when it is too wet, because compaction can restrict roots.
Worked example
Target 300 plants/m². Thousand-grain weight is 45 g, germination 95% and field establishment 90%. Seeds needed = 300 ÷ (0.95 × 0.90) = 351 seeds/m². Seed mass = 351 × 45 g ÷ 1000 = 15.8 g/m². Multiply by 10,000 m²/ha: 158 kg/ha. The reasoning adjusts the target population for two separate losses, then converts grain number to mass using thousand-grain weight.
Traps
Do not use the target plant population as the seed rate. Keep units consistent: g/m² to kg/ha is ×10. Do not ignore germination or field establishment. Avoid spraying without identifying the problem or exceeding label rates, and do not harvest or store at unsuitable moisture. A calculated seed rate is only a starting point; check drill calibration in the field.