Influence of soil pH on NO x and N2O emissions from bovine urine applied to soil columns

摘要

The nitrous oxide (N2O) molecule is both a greenhouse gas and a precursor to the formation of nitric oxide (NO) in the stratosphere, which is subsequently involved in catalytic destruction of ozone (O3). Tropospheric NO can form NO2 with both gases (NO x ) able to react with volatile organic compounds to produce the detrimental O3 molecule. Information on how NO and N2O emissions respond to agricultural management is lacking. Limited data suggest N2O emissions following bovine urine deposition may vary with soil pH. This work hypothesised that soil liming would also reduce NO x emissions due to enhanced nitrification and reduced opportunity for HNO2 formation as soil pH increased. Bovine urine was applied (575 kg N/ha) to repacked soil cores (34% water-filled pore space) that ranged in pH from 4.4 to 7.6, and these were maintained at 21°C. With the exception of the pH 4.4 treatment, increases in NO–N fluxes occurred during the first 11 days, when nitrification was proceeding. Increasing the initial soil p...