Nitrous oxide emission from soil and from a nitrogen-15-labelled fertilizer with the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP)

Abstract

Mineral-N fertilization can lead to a short-term enhancement of N2O emission from cultivated land. The aim of this field study was the quantitative determination of the short-term N2O emission after application of a fertilizer with the new nitrification inhibitor (NI) 3,4-dimethylpyrazole phosphate (DMPP) to winter wheat. NO3– and NH4+ fertilizers labelled with 15N in liquid and granulated form were used in specific fertilizer strategies. N fertilizers with higher NO3– contents caused higher N2O emission than NH4+ fertilizers. For fertilizers with NIs, used in simplified fertilizer strategies with fewer applications and an earlier timing of the N fertilization, the N2O release was reduced by about 20%. Of the total N2O emission measured, 10–40% was attributed to fertilizer N and 60–90% originated from soil N. Besides the fertilizer NO3–-N, the microbial available-N pool in the soil represented a further important source for N2O losses. Compared to liquid fertilizers, the application in granulated form led to smaller N2O emissions. For fertilizers with NIs, the decrease in the N2O emission is mainly due to their low NO3–-N content and the possibility of reducing the number of applications.