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Effectiveness of Nitrapyrin in Controlling Nitrification of Fall and Spring‐Applied Anhydrous Ammonia 1
Author(s) -
Hendrickson L. L.,
Walsh L. M.,
Keeney D. R.
Publication year - 1978
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1978.00021962007000050003xa
Subject(s) - nitrification , anhydrous , chemistry , agronomy , ammonia , nitrogen , sowing , fertilizer , zoology , biology , organic chemistry
Fertilizer N applied in the fall for the next growing season is often less efficient than N applied closer to the time of plant use. Efficiency might be greatly improved by maintaining the N as NH 4 through the use of the nitrification inhibitor, Nitrapyrin [2‐chloro‐6(trichloromethyl)pyridine] (NI). To evaluate this hypothesis, field trials were established during 1975 to 1977 in south central Wisconsin using 84 to 168 kg/ha N applied as anhydrous ammonia with and without 0.55 kg/ha NI. Nitrogen was applied in early or late fall, or just prior to planting corn ( Zea mays L.). The soil sampling data showed that NI provided excellent control of nitrification on the site from which yields were obtained. By early May more than 50% of the fall‐applied NH 3 was still in the NH 4 form when treated with NI, while more than 80% was nitrified in the untreated bands. Despite the rapid nitrification of untreated NH 4 at this site, little inorganic N was apparently lost from the rooting zone. Therefore no yield or N uptake response by the crop to NI was obtained. Nitrapyrin was much less effective in controling nitrification on a poorly‐drained site adjacent to the yield trials. Soil at this site also had higher pH and organic matter, and we found large inorganic N deficits in the sampled zone. These deficits, which can likely be attributed to denitrification, were significantly reduced by NI treatment.