Effects of Nitrification Inhibitors on Soil Nitrification and Ammonia Volatilization in Three Soils with Different pH

• Main Authors: Lei Cui, Dongpo Li, Zhijie Wu, Yan Xue, Furong Xiao, Lili Zhang, Yuchao Song, Yonghua Li, Ye Zheng, Jinming Zhang, Yongkun Cui
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Agronomy
• Subjects: ammonium nitrogen; nitrate nitrogen; nitrification inhibitor; nitrification; ammonia volatilization
• Online Access: https://www.mdpi.com/2073-4395/11/8/1674

The application of nitrification inhibitors (NIs) is considered to be an efficient way to delay nitrification, but the effect of NIs combinations on soil nitrification and ammonia (NH₃) volatilization are not clear in soils with different pH values. In this study, we explored the effect of nitrapyrin (CP) and its combinations with 3, 4-dimethylepyrazole phosphate (DMPP), dicyandiamide (DCD) on the transformation of nitrogen, potential nitrification rate (PNR), and ammonia (NH₃) volatilization in a 120-day incubation experiment with three different pH values of black soil. Treatments included no fertilizer (Control), ammonium sulfate (AS), AS+CP (CP), AS+CP+DMPP (CP+DMPP), and AS+CP+DCD (CP+DCD). The application of NIs significantly decreased NO₃⁻-N contents and potential nitrification rate (<i>p</i> < 0.05), while significantly increased NH₄⁺-N contents (<i>p</i> < 0.05), especially CP+DCD and CP+DMPP were the most effective in the neutral and alkaline soils, respectively. In the acid soil, CP significantly increased total NH₃ volatilization by 31%, while CP+DCD significantly reduced by 28% compared with AS. However, no significant difference was found in NH₃ volatilization with and without NIs treatments (<i>p</i> > 0.05) in the neutral and alkaline soils. In conclusion, the combined nitrification inhibitors had the better efficiency in all three tested soils. CP+DCD and CP+DMPP are the most effective in inhibiting soil nitrification in the clay soils with higher pH value and lower organic matter, while CP+DCD had the potential in mitigating environment pollution by reducing N loss of NH₃ volatilization in the loam soil with lower pH value and higher organic matter. It provided a theoretical basis for the application of high efficiency fertilizer in different soils. Further studies under field conditions are required to assess the effects of these nitrification inhibitors.