Characteristics of urease/nitrification inhibitors in reducing nitrogen losses in farmland soils

Excessive application of nitrogen fertilizer aggravates nitrogen losses from agricultural soils, with effects such as increasing ammonia(NH3) volatilization, nitrous oxide(N2O) emissions, and nitrate(NO3-) leaching, which can reduce air and water quality and have a negative impact on global climate. Urease inhibitors and nitrification inhibitors can delay the transformations of soil nitrogen and reduce the negative effects of soil-reactive nitrogen. Both have been widely used in agricultural production, as N-butylthiophosphoryl triamine (NBPT), 3, 4-dimethylpyrazole phosphate(DMPP), and dicyandiamide(DCD). The mechanisms of urease inhibitor(NBPT) and nitrification inhibitors(DMPP, DCD) in agricultural soils and their effects on the environment and agronomy were comprehensively reviewed in this study, revealing the main factors affecting the effectiveness of its application. Many studies have shown that NBPT combined with chemical nitrogen fertilizer and/or organic fertilizer could reduce NH3 volatilization, N2O emission, and NO3- leaching, as well as improve crop yield and quality and nitrogen-use efficiency. Similarly, as nitrification inhibitors, both DCD and DMPP could reduce soil N2O emissions and NO3- leaching, increase crop yield, and increase soil NH3 volatilization loss. The inhibition efficacy of urease/nitrification inhibitors is related to the type of nitrogen inhibitors, the form and rate of nitrogen fertilizer, whether rainfall or irrigation is employed, and edaphic conditions such as soil pH and clay content. Therefore, the characteristics and effects of urease/nitrification inhibitors should be considered for scientific and practical applications.