A comparison of CH4 emissions from coastal and inland rice paddy soils in China

To achieve regional CH4 regulation, it is essential to understand the differences in methane (CH4) emissions from inland and coastal rice paddy soils. The aim of this study was to compare the CH4 emissions from coastal and inland rice paddy soils in China. A statistical analysis was conducted using a database compiled from published references, soil property datasets, and field experimental data. The results showed that during the growing seasons, the average CH4 emissions from inland rice paddy soils were significantly higher than those from coastal paddy soils (p < 0.05). For both inland and coastal zones, single and multiple drainage practices greatly decreased CH4 emissions from rice paddy soils (p < 0.05). Organic fertilizer application increased CH4 emissions from Chinese rice paddy soils (p < 0.05). Seasonal CH4 emissions decreased significantly with increases in longitude (p < 0.001) and latitude (p < 0.05). Total nitrogen, available P, soil organic matter, and some exchangeable cations (e.g., Al3+, Mg2+, and Ca2+) greatly affected the CH4 emissions from rice paddy soils. The results of this study can provide information useful to the development of assessment models for CH4 budgets and the best management practices for CH4 mitigation in rice paddy soils at the national scale.