Analysis of factors controlling soil N2O emission by principal component and path analysis method

Abstract

Nitrous oxide (N2O) is a potent greenhouse gas. Mitigating N2O emission is critical for combating global climate change and improving the ecological environment. Many studies have focused on factors affecting N2O emission from agricultural soils, but rarely on the relationship among these factors. In the present study, continuous measurement on N2O emission was conducted in a maize system in Griffith, Australia and the relationships between N2O emission, soil properties and weather conditions were examined. Principal component analysis and path analysis were used to analyze these data in correlation coefficient and the direct and indirect effects to N2O emission. Results indicated that (1) the major factors affecting N2O emission were WFPS, mineralized nitrogen (Mineral N), daily mean temperature (T mean) and CO2 concentration. The factors of direct influence N2O emission were following Mineral N, CO2, WFPS, and T mean. The indirect influence N2O emission was following T mean, WFPS, Mineral N, and CO2 concentration. (2) The standard multiple regression describing the relationship between N2O emission and its major factors were Y = −37.162 + 0.5267 X 1 + 0.4331 X 2 + 0.3014 X 3 + 0.2392 X 4 (r = 0.924, p < 0.01, n = 151), where Y is N2O emission, X 1 is Mineral N, X 2 is CO2, X 3 is WFPS and X 4 is T mean. (3) N2O emission from agricultural soils can be monitored and mitigated through improved management practices such as irrigation, straw retention and fertilizer application.