Nitrogen watch

This page tracks spring rainfall and identifies danger areas that are on track to have problems with nitrogen loss and deficiency in corn. This is a serious production and environmental problem that is estimated to cost Midwestern corn producers 2 billion bushels total from 2008 to 2011.

  • Well- and moderately well-drained soils

    well drained midwest may 26th

    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 with diagonal shading 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.

  • Poorly- and somewhat poorly-drained soils

    poorly drained midwest may 26th

    Poorly-drained soils lose N mainly by denitrification, which is very temperature-sensitive. My rule of thumb is that wet conditions in May and June cause denitrification losses, but losses in April are minimal.

    Areas with diagonal shading are ‘danger areas’ that are on track to have 12 or more inches of rainfall from May 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.


Previous weeks


Well- and moderately well-drained soils

Poorly- and somewhat poorly-drained soils

May 19 (PDF) May 19 (PDF)
May 12 (PDF) May 12 (PDF)
May 5 (PDF)

Archive

Nitrogen watch information through 2015 is archived for use and for reference.

Nitrogen watch archive