Plant Production and Management
Core concepts
Plant production is driven by genotype × environment × management. Understand photosynthesis and respiration, the growth stages of a crop (establishment, vegetative, reproductive, grain fill, maturity), and how temperature, water, light and nutrients limit yield. Know phenology: vernalisation requirements, photoperiod response and thermal time (growing degree days), and why matching a cultivar's maturity to the growing-season length and frost risk is critical.
Agronomic practice
Be able to justify decisions on sowing time and depth, plant density and row spacing, seedbed preparation, variety selection (disease resistance, quality grade, maturity), fertiliser timing (basal versus top-dressing), irrigation scheduling and integrated weed, pest and disease management. Understand yield components - plants per square metre × heads per plant × grains per head × grain weight - and how management shifts each. Know soil water-holding capacity, root-zone depth and water-use efficiency.
Traps
- Confusing potential yield (climate-limited) with water-limited or nutrient-limited yield.
- Assuming more nitrogen always means more yield; excess causes lodging, disease and quality loss.
- Mixing up source (leaves producing assimilate) and sink (grain filling).
- Ignoring quality parameters (protein, oil, screenings) when the question asks about profitability.
Worked example
A wheat crop has 180 plants/m², 2.5 heads per plant, 32 grains per head and a grain weight of 40 mg. Yield = 180 × 2.5 × 32 × 0.040 g = 576 g/m² ≈ 5.76 t/ha. If the question states a target of 6.5 t/ha, the gap must be closed through one of the four components - for example, more heads per plant via earlier sowing or higher nitrogen at tillering.