3,4-Dimethylpyrazole (phosphate)

3,4-Dimethylpyrazole (phosphate) (3,4-DMPP) is an inhibitor of nitrification deemed safe by extensive standard toxicology and ecotoxicology tests. When utilized on crops, 3,4-DMPP prevents nitrogen loss from soil, increases nitrogen use efficiency, and boosts crop yields. However, a meta-analysis found no influence of 3,4-DMPP on net crop yield, although it may boost yields in alkaline soil. 3,4-DMPP may be less effective in acidic soils and in the post-harvest period. DMPP interferes with ammonia monooxygenase from ammonia-oxidizing bacteria (AOB) and archaea (AOA) but may not directly affect AOB, AOA, and non-target populations.