Nitrogen watch for well- and moderately well-drained soils

Well-drained soils are most vulnerable 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. Nitrogen loss in these areas is likely to result in nitrogen deficiency of corn, milo, and cotton. If nitrogen was sidedressed, risk is considerably lower than if applied all pre-plant. Sidedress ammonia has little risk of loss. For fields with deficiency symptoms or all N applied pre-plant, consider application of additional N fertilizer.

Aerial photos can help to assess the need for additional N on corn between waist-high and tasseling and are available from AgriVision .