How forages reduce nitrate leaching
- Forages can reduce nitrogen in the diet, which reduces the amount of nitrogen excreted in urine
- An actively growing crop can capture more urinary nitrogen before it drains away, due to the deeper root systems.
There are three cropping strategies that address nitrate leaching.
Plantain in pasture
Plantain can dilute urine, increase nitrogen uptake from the soil by plants and reduce nitrification rate in the soil. This can improve the farm's nitrogen use efficiency.
Low nitrogen crops such as fodder beet and cereals
Fodder beet is a low crude protein (and thus low nitrogen) feed and reduces the amount of nitrogen eaten and excreted in the urine. It reduces nitrate leaching if it substitutes high nitrogen pasture or supplements in the animals' diet
Catch crops replace fallow ground, increase total annual dry matter yield per hectare and take up nitrogen available from mineralisation and urine deposited during winter grazing.
Due to variations in regional and on-farm climate, soil types and infrastructure, individual solutions will need to be designed in consultation with a local agronomist.
Forages for reduced nitrate leaching
Plantain is highly palatable to animals, establishes rapidly, is pest tolerant and has a high mineral content.
Fodder beet is a low nitrogen root crop with a high yield potential.
The purpose of a catch crop is to increase annual dry matter production, to take up soil mineral and urine nitrogen and to reduce the risk of leaching or runoff.