Fertilization Methods Effect Spring Wheat Yield and Soil CH4 Fluxes in the Loess Plateau of China.

Dryland agricultural soils are recognized as significant sites of methane (CH4) absorption, making them integral to the global CH4 budget. Nitrogen fertilization is commonly used by growers in these regions to obtain optimal wheat yields, but it is unclear how various methods may affect CH4 absorption. Therefore, we conducted two years of field studies in the rain-fed agricultural experimental station in the semi-arid Loess Plateau in northwest China to test how four fertilization methods altered different crop and soil characteristics. Plots consisted of a popular spring wheat variety treated with either no fertilizer (CK), nitrogen fertilizer (N), organic manure (M), or a combination of nitrogen and organic manure (NM). We analyzed the effects each fertilization methods had on both yield and soil CH4 flux. The results indicated that these soils act as a net sink of CH4. The NM treatment significantly increased wheat yield, while the N treatment significantly reduced CH4 absorption. Furthermore, soil CH4 absorption under each treatment had a clear temporal pattern, which peaked during the flowering stage. Our principal component analysis and linear regression analysis illustrated how CH4 fluxes were significantly positively or negatively correlated with soil total nitrogen, nitrate nitrogen, and temperature (P < 0.05), potentially explaining 40% of the CH4 variability. In conclusion, our results indicate that the co-application of nitrogen and organic manure can both support optimal wheat yield and effectively reduce the risk of CH4 emissions. [ABSTRACT FROM AUTHOR]