Nitrous oxide emission from two acidic soils as affected by dolomite application

Abstract

The effect of dolomite (CaMg(CO3)2) application on nitrous oxide (N2O) emission was examined in a laboratory study with soil from a rice paddy–rapeseed rotation (PR soil, pH 5.25) and from a rice paddy–fallow–flooded rotation soil (PF soil, pH 5.52). The soils were treated with 0, 0.5 (L) and 1.5 (H) g dolomite 100 g–1 soil. Results showed that N2O emissions were higher in control treatments (untreated dolomite) in both soils. Application of dolomite decreased N2O emissions significantly (P ≤ 0.001) as soil pH increased in both soils. The H treatment was more effective than the L treatment for the reduction of N2O emissions. The H treatment decreased the cumulative N2O emissions by up to 73.77% in PR soil and 64.07% in PF soil compared with the control. The application of dolomite also affected concentrations of dissolved organic carbon, microbial biomass carbon, ammonium and nitrate in soils, which related to N2O emission. The results suggest that dolomite not only counteracts soil acidification but also has the potential to mitigate N2O emissions in acidic soils.