The Influence of Nitrification Suppressants on the Rate of Ammonium Oxidation in Midwestern USA Field Soils1
- Burns R. Sabey2
The effectiveness of 2-chloro-6-(trichloromethyl) pyridine, 2-amino 4-chloro 6-methyl pyrimidine, and a resinous polymer coating in suppressing nitrification in the field was studied. Soil samples treated with (NH4)2SO4 alone and with (NH4)2SO4 plus the above materials, were placed in plastic bags and buried in field plots and allowed to incubate during the fall, winter and spring periods. Determinations for NH4+-N and NO3--N were made throughout the incubations.
Nitrate-N accumulation occurred at rates as high as 2.5 ppm/day prior to April 15 in samples treated with (NH4)2SO4 alone. Samples treated with the resinous coated (NH4)2SO4 fertilizer had higher NO3--N accumulation rates (up to 4.1 ppm NO3--N/day), whereas samples treated with (NH4)2SO4 and 2-chloro-6-(trichloromethyl) pyridine or 2-amino 4-chloro 6-methyl pyrimidine had rates of nitrification only as high as 2.3 and 1.6 ppm NO3--N/day, respectively, prior to April 15. Although 2-amino 4-chloro 6-methyl pyrimidine appeared slightly more effective after the end of April than 2-chloro-6-(trichloromethyl) pyridine in suppresing nitrification, there were relatively small differences. Both compounds, added according to recommended rates delayed rapid nitrification for about 1 month.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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