Michigan State University Extension
Soils & Soil Management - Fertilizer - 06109717
07/10/97
Nutrient Management to Protect Water Quality Extension Bulletin WQ-25, January 1996
Maurice L. Vitosh and Lee W. Jacobs Extension Soil Specialists Department of Crop and Soil Sciences Michigan State University
Crop producers in many states have successfully used Vitrification inhibitors to delay the conversion of ammonium N to nitrate N. Preventing rapid conversion of ammonium to nitrate can reduce the amount of nitrate N that is available for denitrification or leaching early in the season. Table III gives the potential for economic response to the use of Vitrification inhibitors on corn for various times of the year and for various soil types.
Crop producers should consider using nitrification inhibitors when it is not feasible to use delayed N applications, such as by sidedressing or applying through an irrigation system. Nitrification inhibitors can be beneficial if N applications are made early and leaching or denitrification conditions exist. The amount of N used is very critical to the successful use of a Vitrification inhibitor. Vitrification inhibitors will work best when the amount of N applied is slightly deficient. If the rate of N fertilizer applied is adequate or excessive, no benefits can be expected. In summary, Vitrification inhibitors can improve N recovery when used appropriately, but they should not be used as a substitute for following other recommended management practices. ==================================================== Table III. Potential for an economic response to the use of nitrification inhibitors with anhydrous ammonia on corn for different application times and soil management groups.
Time of nitrogen application
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Soil Late Early Late
management fall spring spring Side-
group <50 F <50 F >50 F dress
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Clays(0,1) Good Good-fair Poor-fair Poor
Clay loams(1.5)Good-fair Fair-good Poor-fair Poor
Loams(2.5) Fair-good Fair Fair Poor
Sandy loams(3) Fair Fair Fair Poor
Loamy sand(4) Fair-poor Fair Fair Poor
Sands(5) Poor-fair Fair-poor Fair Poor
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Key:
Good=Economic response expected at least 60% of the
time
Fair=Economic response expected 40-50% of the time
Poor=Economic response expected less than 30% of the
time
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