Nitrification Inhibitors Impact on Nitrous Oxide Emission and Ammonia Volatilization: A Sustainable Measure Toward a Hygienic Environment

Abstract

Nitrogen (N) application to agricultural fields warrants curtailing nitrous oxide (N2O) emission and ammonia (NH3) volatilization for improved use efficiency with a less environmental footprint of N. As a means of mitigating N2O emissions, the efficacy of nitrification inhibitors (NIs) is well established but the efficacy of NIs in reducing NH3 volatilization is not well understood. The study investigated the efficacy of neem oil, pomegranate leaf extract, and dicyandiamide (DCD) coating on prilled urea for reducing N2O emissions and the trend of NH3 release using static air closed chamber technique in an incubation room. The results showed that all NIs reduced N2O flux in the order of 37%–42% by DCD urea, 19%–34% by neem oil coated urea (NOCUs), and 11%–16% by pomegranate leaf extract coated urea (PLECU). However, over uncoated urea, 43%–54% NH3 flux was increased by DCD, 10%–32% by NOCUs, and significantly the least increase (5%–14%) in NH3 cumulative flux was shown by PLECU. Dicyandiamide significantly reduced N2O flux more than all other treatments, and PLECU showed the least increase in NH3 emission when compared with other coated treatments. Hence, it is suggested that neem oil and pomegranate leaf extract could be used successfully not only for mitigating N2O emission, but also lessen environmental damages in association with managed N intense agriculture. Moreover, research focus on the increase in NH3 volatilization using DCD needs serious attention, especially in alkaline calcareous soils.