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ABSTRACT
Using nitrification inhibitors is a well-established fertilizer best management practice affording improved fertilizer use efficiency in crop production that may benefit profitability, crop quality, and the environment. The environmental benefit of nitrification inhibitor use in terms of managing N mobility in agroecosystems must be balanced against any environmental costs associated with the practice itself. Nitrapyrin exhibits multiple routes of degradation in the environment (hydrolysis, aerobic and anaerobic metabolism), which along with sorption and volatilization restrict its ability to mobilize to ground or surface water. Management practices (timing, rate, and method of application) that maximize nitrapyrin efficacy, additionally, favor the ultimate fate of nitrapyrin to occur by the linked processes of sorption and degradation within the upper soil profile. Thus, when nitrapyrin is used as a best management practice conducive of optimal fertilizer use efficiency, its environmental fate and behavior attributes minimize potential environmental exposure.
Abbreviations: UAN, urea ammonium nitrate; DAT, days after treatment HEEE, high end exposure estimates.
Improved N use efficiency in crop production benefits profitability, crop quality, and the environment. The use of nitrification inhibitors is well established as a fertilizer best management practice affording improved fertilizer use efficiency (Meisinger et al., 1980; Vitosh et al., 1995) and therefore lessening the negative environmental effects of N mobilization from agroecosystems.
Nitrapyrin has been used for stabilization of fertilizer N for more than 25 years. The chemical inhibits the nitrification process by acting selectively on Nitrosomonas spp. to restrict the conversion of NHS to NOZ . Maintenance of soil N in the NHa form decreases the susceptibility for N leaching and/or denitrification and therefore increases potential N availability for crop growth.
The benefit of any prescriptive practice to reduce N contamination of water resources must be balanced against the environmental safety of the practice itself. Therefore, the utility of nitrapyrin use as an N fertilization best management practice is dictated by its environmental fate and how this influences environmental behavior as well as N use efficiency. This review and analysis evaluates the environmental fate of nitrapyrin both as it relates to potential exposure and to N mobility in agricultural settings. A rich body of literature describes the environmental behavior of nitrapyrin specifically as it relates to efficacy of N stabilization (Meisinger...