Contrasting response of two grassland soils to N addition and moisture levels: N2O emission and functional gene abundance

Abstract

Purpose: Nitrification and denitrification processes dominate nitrous oxide (N2O) emission in grassland ecosystems, but their relative contribution as well as the abiotic factors are still not well understood. Materials and methods: Two grassland soils from Duolun in Inner Mongolia, China, and Canterbury in New Zealand were used to quantitatively compare N2O production and the abundance of bacterial and archaeal amoA, denitrifying nirK and nirS genes in response to N additions (0 and 100 μg NH4 +–N g−1 dry soil) and two soil moisture levels (40 and 80 % water holding capacity) using microcosms. Results and discussion: Soil moisture rather than N availability significantly increased the nitri..