Effects of nitrification inhibitors on crop productivity, mineral nitrogen concentrations, and gaseous emissions under field conditions: A meta-analysis of recent decades

Nitrification inhibitors (NIs) are crucial for enhancing nitrogen use efficiency (NUE), minimizing nitrogen losses, and reducing environmental impacts in agriculture; however, their effectiveness under varying conditions remains unclear. A present meta-analysis assessed how NIs affect crop yields, nitrogen recovery efficiency (REN), soil ammonium (NH 4 + -N), nitrate (NO 3 - -N), ammonia (NH 3 ), and nitrous oxide (N 2 O) emissions, and the results revealed that NIs increase crop yield by an average of 4.7 % with Nitrapyrin, DCD, and DMPP showing specific yields increase of 6.11 %, 4.61 %, and 3.79 %, respectively. Yield increases are most significant with nitrogen rates below 250 kg ha -1 , while rates above this threshold lead to yield declines of 1.76 %. The application of NIs improved REN by 13.14 %, while soil NH 4 + -N levels increased by 42.04 % with the highest increase occurring at lower nitrogen application rates at < 150 kg ha -1 (83.49 %). NIs also reduced soil NO 3 - -N levels by 24.65 % with DCD showing the greatest reduction at -28.17 %, while DMPP had the smallest reduction at -20.04%. the study also revealed cumulative NH 3 volatilization increased by 12.06 %. Among them, DCD and DMPP caused minor increases of 8.52 % and 8.13 %, respectively, while nitrapyrin had little effect, resulting in a 23.42 %. NIs also significantly lowered cumulative N 2 O emissions by 47.39 % relative to the control. Overall, NIs help regulate soil nitrogen levels and mitigate greenhouse gases by slowing nitrification. Their effectiveness may vary based on factors like soil type and management practices, highlighting the need for further research to optimize their use in sustainable nitrogen management strategies. • •Meta-analysis synthesized recent field studies on nitrification inhibitor effects. • •Nitrification inhibitors significantly increased crop yield, nitrogen recovery efficiency (REN), and soil ammonium • •Application reduced N 2 O emissions and nitrate leaching under field conditions. • •NIs help regulate soil nitrogen levels and mitigate greenhouse gases by slowing nitrification