A recent study published in the Journal of Soils and Sediments by He et al., investigated the combined effects of nitrification inhibitors (NIs) and soil amendments like straw and biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More on soil nitrification and nitrous oxide (N2O) emissions. Nitrification inhibitors are compounds that can reduce the rate of nitrification, a process that can lead to nitrogen loss from agricultural soils. The study explored how combining two different NIs with straw or biochar affects soil nitrogen processes.

The researchers found that both a synthetic nitrification inhibitor (DMPP) and a biological nitrification inhibitor (MHPP) significantly reduced gross nitrification rates. DMPP was more effective, reducing nitrification by 54.7%, compared to MHPP’s 31.2% reduction. Interestingly, biochar application alone increased soil nitrification rates, but combining it with NIs mitigated this effect. Straw, on the other hand, slightly inhibited nitrification but increased N2O emissions. However, when straw was co-applied with NIs, the inhibitory effect on nitrification was enhanced, and N2O emissions were reduced.

The study also examined the impact of these treatments on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), which are crucial microorganisms in the nitrification process. The findings indicated that NIs reduced the abundance of the amoA gene (a key gene for ammonia oxidation) in both AOA and AOB. AOB communities were found to be more sensitive to NIs than AOA communities.

Overall, this research suggests that combining NIs with straw or biochar can have synergistic effects on soil nitrification and N2O emissions. The co-application of DMPP with biochar was particularly effective in inhibiting nitrification and N2O production, which could help retain inorganic nitrogen in the soil. These findings contribute to developing more effective strategies for managing nitrogen in agricultural systems, reducing environmental losses, and improving soil health.

Source: He, X., He, J., Shen, H., Zeng, Z., Zhao, D., Cheng, C., & Lan, T. (2025). Co-application of nitrification inhibitors with straw or biochar yielded varying effects on soil nitrification rate, N_2O emissions, and ammonia oxidizers. Journal of Soils and Sediments, 0(0), 1–12.