Pulse emissions of N 2O and CO 2 from an arable field depending on fertilization and tillage practice

Abstract

Nitrous oxide (N 2O) emissions from soil are characterized by strong emission pulses. Although several mechanisms are known to create them, pulses are difficult to predict. Currently there is no established systematic way to identify pulses from long-term static chamber measurement results. In this study we suggest a simple algorithm for pulse identification. The algorithm was applied on time series of N 2O and carbon dioxide (CO 2) fluxes from a field study on the long-term impact of fertilization and tillage practice. Between 4 and 9% of N 2O values were pulse values; 20–60% of total emission was emitted as pulses. Minimum tillage resulted in more pulses than plowing. In contrast, long-term averages of N 2O losses from nitrogen (N) fertilizer were similar (3–4%) for all management practices. N 2O emissions per crop yield for increased fertilization practice were double the values for reduced fertilization practice independent of tillage practice. CO 2 emission pulses were scarce and there was no significant effect of management practice on CO 2 pulse probability.