Key Points
- Weather records for Gisborne were analysed to determine the size and frequency of rainfall events that might cause leaching of fertiliser N applied to maize crops. This was supplemented with soil mineral N measurements in paddocks under different land uses in July 2005 and again in October 2005 after a large rain event (>180 mm).
- In this region there is a low risk of fertiliser N leaching because of high water holding capacity soils, infrequent high rainfall events during spring and summer, and good fertiliser N management by the growers. This is supported by the amount and distribution of soil mineral N, which is the same for maize and paddocks.
- The high rainfall event of October 2005 moved fertiliser to a depth of 30-60 cm but not below.