From synthetic to biological nitrification inhibition: Advancing stabilization of organic fertilizers

Fertilizer type plays a critical role in nitrogen (N) cycling, influencing nitrous oxide (N₂O) emissions, soil mineral N dynamics, and microbial communities. Understanding these interactions is essential for developing sustainable fertilization strategies that balance agricultural productivity with environmental protection. This study examined the effects of mineral and organic fertilizers (OFs) on N transformations and evaluated the efficiency of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) in mitigating N₂O losses. Results showed that OFs exhibited variable impacts on N₂O emissions depending on their composition and C/N ratio. DMPP effectively reduced nitrification-driven N₂O emissions, particularly in treatments with high ammoniacal N content. However, its efficiency was limited with animal-based OFs, suggesting a complex interaction between fertilizer properties and inhibitor effectiveness. DMPP had not direct impact on soil microbial diversity but specifically targeted the Nitrosomonaceae family and Nitrospira class. Beyond synthetic inhibitors, biological nitrification inhibition (BNI) emerged as a promising alternative, which we explored using rhizospheric soils from wheat landrace Persia 44 and white mustard (cv. Pole Position and cv. Verdi). These soils significantly reduced N₂O emissions, particularly when combined with OFs. The integration of BNI with organic fertilizers, especially liquid digestate, represents a promising strategy for reducing N losses while maintaining soil fertility. This study underscores the need for tailored fertilization strategies that combine chemical and biological tools to optimize N use efficiency and support environmentally sustainable agriculture.