Effects of Nitrification Inhibitors on Nitrogen Transformation in Different Soils

The effects of nitrification inhibitors 3,4-dimethylpyrazole phosphate(DMPP) and dicyandiamide(DCD) on soil nitrogen transformation in different soils was investigated in a lab incubation experiment.The results indicated soil pH and NH4 +-N concentrations were increased to maximum quickly and then decreased gradually,but NO3--N concentrations and apparent nitrification rates were increased with the time of incubation in all treatments.The apparent nitrification rates were urea alone 1%DMPP 10%DCD in four types of soil.The application of DMPP and DCD induced nitrification process lag behind at least 28 d in alkaline soils,and resulted in the decreased amounts of NO3--N in acid soils,especially in red soil,which were relatively less than that in in alkaline soils.In conclusion,10% DCD was more effective than 1% DMPP,and the effectiveness of the two nitrification inhibitors was different in alkaline soils and acid soils.