Nitrogen watch for poorly- and somewhat poorly-drained soils

Click on a number corresponding to the one on the map to see a July 7, 2009 aerial photo and estimated yield loss map: 1, 2, 3, 4, and 5.

Poorly drained soils are most vulnerable to nitrogen loss from denitrification. This process is very temperature-sensitive and doesn’t start in earnest until May 1. Areas shown in cross-hatch are ‘danger areas’ that are on track to have 12 or more inches of rainfall from May 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.