Nitrogen watch for well- and moderately well-drained soils
Well-drained soils are vulnerable mainly to nitrogen loss from leaching. This process can start shortly after fertilizer application (with some delay for ammonia). We have used April 1 to represent a preplant N application date. For ammonia or for applications later than April 1, risk is lower; for applications before April 1, risk is higher.
Areas shown in cross-hatch are ‘danger areas’ that are on track to have 16 or more inches of rainfall from April 1 to June 30. This does not mean that significant loss of N has already happened, just that producers in these areas should be watchful and aware of the potential for N loss and deficiency.
Aerial photos can help to assess the need for additional N on corn between waist-high and tasseling and are available from AgriVision.