Key Points
- By reducing fertiliser inputs to maize grown on high fertility dairy farm effluent paddocks, excess soil nutrients may be utilised without compromising maize silage yields.
- Three fertiliser treatments (nil, low, full) were replicated at each of four trial sites on Waikato dairy farms. All sites had been in long-term pasture and had effluent applied for a number of years.
- There was no yield response to fertiliser inputs at any site. Substantial nitrogen was released in the breakdown of soil organic matter; enough to meet crop requirements even in the nil fertiliser treatments.
- At harvest, large amounts of soil mineral N were found in the fully fertilised plots. Pasture sown in autumn after maize will mop up some of this excess soil N.
- Substantial economic and environmental gains can be made by reducing fertiliser inputs to maize silage crops grown in high fertility dairy paddocks cultivated for the first time.