Key Points
Results have shown that cultural practices which impact on: timing of operations, crop residue levels and incorporation depth, fallow periods, soil moisture and soil nitrogen dynamics, all affect subsequent maize crop performance and overall system (annual) profitability. More specifically:
- Maize sowing time was shown to be the key driver in overall farm profitability. For every week maize planting was delayed past the optimum sowing date, up to 0.5t/ha yield loss was incurred.
- If well managed, winter cash crops of cereals and annual ryegrass can provide moderate levels of revenue but this benefit was frequently offset by delays in sowing and lower subsequent maize grain yields compared to winter fallow.
- Cost of growing winter green-manure legumes (>$500/ha) typically outweighed the cost of applying N fertilisers to the subsequent maize crop.
- The type of winter crop grown can affect subsequent maize production differently from season to season.
- The performance of various winter cover crops varied from site to site and year to year, making recommendations difficult. However, there was little difference among all nonlegume crops tested.
- If planning to grow winter cover crops, care should be taken with maize hybrid selection. Short season hybrids should be considered to allow earlier planting and later harvesting of winter cover crops.