Catch crops
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A catch crop is a type of crop sown to utilise excess nitrogen in soils, preventing its loss to the environment. This page highlights recent trials in New Zealand that found cereals to be more effective than grass for this purpose after winter grazing. Planting catch crops earlier increases their effectiveness in reducing nitrate leaching and can even boost the annual yield of a paddock. Recommendations include minimising fallow land, considering catch crops to absorb urinary nitrogen, and maintaining grass buffers to avoid sediment loss. These practices can enhance soil management on your dairy farm.
A catch crop is any crop that is sown with the primary objective of utilising excess nitrogen in soils that otherwise may be lost to the environment through leaching.
Trials completed in Canterbury, Waikato and Southland have found that:
- cereals were more effective than grass species following winter grazing
- the earlier the crop is planted, the greater the opportunity to reduce nitrate leaching
- catch crops can increase total annual yield of a paddock.
Bare ground continues to be a risk for overland flow of nutrients and soil from the paddocks after grazing has finished.
- Minimise the time that the land is fallow. The establishment of new pasture or a catch crop will reduce overland flow risk.
- Consider planting a catch crop to take up some of the urinary nitrogen left from the previous winter grazing.
- Maintain the grass buffers to ensure sediment is not lost from the paddock.
| Sowing date | Southland | Canterbury | Hawke's Bay | Waikato |
| June | 22% | 41% | 20% | 34% |
| July | 17% | 33% | 7% | 27% |
| August | 8% | 26% | 4% | 19% |
| September | 0% | 11% | 2% | 6% |
See the Catch crops page for more information.