The effect of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrifying organism populations under in vitro conditions

The application of nitrification inhibitors is a technique to reduce the nitrate concentration on leachates that delay ammonium oxidation by reducing the activity of ammonium oxidizing bacteria in soils. Two experiments were carried out in order to estimate the influence of DMPP on the population of ammonium oxidization bacteria under in vitro conditions. In both experiments, three treatments were established. The treatments were the following: a) ammonium oxidization bacteria established in a growing media without fertilizers, b) ammonium oxidization bacteria established in a growing media with Urea, and c) ammonium oxidization bacteria established in a growing media with DMPP. Results obtained showed that the population of the ammonia oxidizing bacteria diminished in the DMPP treatment as compared with the urea and control treatments. In conclusion, DMMP influences on ammonium oxidization bacteria activity being a useful tool in fertilizers strategies to reduce the contamination by nitrates in groundwater.