FOR IMMEDIATE RELEASE: Wednesday, September 29, 2010

CONTACT:
Michael Schommer, Communications Director
651.201.6629, Michael.schommer@state.mn.us

Farmers encouraged to follow best-management practices for fall nitrogen applications

ST. PAUL, Minn. – With fall field work underway, the Minnesota Department of Agriculture (MDA), the Minnesota Crop Production Retailers and soil scientists from the University of Minnesota urge farmers to follow the state’s voluntary best-management practices (BMPs) related to autumn applications of nitrogen.

Historically, anhydrous ammonia has been the primary nitrogen source for fall application. However, recent price increases for anhydrous may now have producers and dealers thinking about alternative sources, particularly urea. Alternative nitrogen sources are generally more soluble, resulting in greater chances of nitrogen loss. In addition, long-term nitrate data show an upward trend in both surface waters and many groundwater aquifers. These factors make it especially important for farmers to review and follow the BMPs for fall nitrogen applications.

The University of Minnesota Research and Outreach Centers provided years of research data that were used to develop regional BMPs. Fall applications of nitrogen on coarse-textured (sandy) soils are not recommended in any regions. A summary of the BMPs is provided below. The full set of BMPs is available online at http://www.mda.state.mn.us/protecting/bmps.aspx.

South Central Region: For corn, a spring pre-plant AA or urea OR split applications of AA, urea, or UAN is the highly preferred method. However, fall-applied anhydrous ammonia (AA) with N-Serve after optimal soil temperatures (6” soil temperature is below 50 degrees F) is acceptable. Do not fall-apply urea, UAN or AA without N-Serve (soil temperature information is available online at http://gis.mda.state.mn.us/maps/csgsoil.htm.)

Southeast: No fall nitrogen application is recommended in this sensitive region.

Southwest and West Central: The use of either AA or urea (incorporated) as a fall nitrogen source on corn is acceptable when optimal soil temperatures (below 50 degrees at 6 inches) are reached. Corn growers may also consider using ESN TM, Agrotain TM or N-Serve TM with the appropriate nitrogen sources in a fall program.

Northwest: The use of either AA or urea (incorporated) as a fall nitrogen source on small grains is acceptable when optimal soil temperatures (below 50 degrees at 6 inches) are reached.

Irrigated/Non-irrigated Sandy Soils: No fall nitrogen application is recommended on coarse-textured soils.

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