Key Points
Nitrate leaching was measured in maize paddocks over four seasons
- Average soil mineral N at the start of the winter was 130kg N/ha. A few paddocks (14%) had high levels of N (over 200kg N/ha) and these high levels were at risk from leaching
- Most paddocks leached less than 50kg N/ha with the average 60kg N/ha. A small number of paddocks had high levels of leaching over 150kg N/ha
- The higher leaching in some areas was directly related to the high rainfall
- Farmers need to aim to minimise N leaching by: applying N fertiliser based on yield and available N (see Maize Calculator), managing paddocks to minimise leaching by sowing winter crops to utilise available N, avoiding cultivating in the winter