Environmental Performance and Economic Trade-Offs of Nitrification Inhibitors in Agricultural Systems: A Systematic Data Synthesis

Growing concerns over food security and greenhouse gas emissions present a dual challenge, as mitigation strategies for one often intensify the other. Nitrification inhibitors (NIs) have emerged as a promising approach to simultaneously reduce nitrous oxide (N2O) emissions and enhance crop productivity. However, their effectiveness is highly dependent on environmental conditions. To systematically evaluate the environmental controls and the economic trade-offs associated with NI application, this study presents a systematic data synthesis of 196 peer-reviewed articles, assessing the performance of three widely used NIs: dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP), and nitrapyrin. The analysis quantifies the influence of key environmental factors (e.g., temperature, soil pH, soil moisture, and soil organic carbon) on NI biodegradability, nitrogen dynamics, and N2O emissions. The results indicate that soil organic carbon has a limited effect on NI performance, whereas temperature emerges as the dominant controlling factor. Among the NIs evaluated, DCD and DMPP demonstrate the highest mitigation efficiencies, achieving N2O emission rates as low as 10−6 and 10−5 kg ha−1 d−1, respectively. An integrated economic analysis further evaluates the cost-effectiveness of NI application across major cropping systems, including corn, rice, and wheat. The findings show that DMPP and nitrapyrin applications yield the highest net economic returns in corn and rice systems (up to 860 USD and 880 USD, respectively), while wheat systems without NI application remain less profitable (approximately 330 USD). Ultimately, this study demonstrates that the practical viability of NIs depends heavily on balancing input costs with crop-specific yield gains, rather than environmental benefits alone. While NIs offer substantial greenhouse gas mitigation potential, their widespread adoption requires careful, site-specific economic evaluation to ensure that yield improvements sufficiently offset the added application costs to achieve truly sustainable agricultural practices.