关键词: 有机肥替代比例, 土壤性质, 气候条件, N₂O排放, NH₃挥发, 硝酸盐淋溶, 产量, 经济效益

Abstract:

【Objective】 Substituting fertilizer by manure is a key measure to reduce the amount of chemical nitrogen (N) fertilizer while maintaining yield. However, the complex relationships among grain yield, environmental costs, and economic benefits of substituting fertilizer by manure were still not clear for wheat production. This study quantified the agronomic, environmental and economic benefits of substituting fertilizer by manure, aiming to provide a reference for the application of substituting fertilizer by manure for wheat production of China. 【Method】 In this study, the effects of substituting fertilizer by manure on the agronomic, environmental and economic benefits of wheat production in China were assessed through Meta-analysis. 【Result】Substituting fertilizer by manure did not reduce wheat yield under the condition that the use of chemical nitrogen fertilizer was reduced by an average of 43%. The replacement ratio of manure was less than 15% and 15%-30%, and the yield significantly increased by 8% and 5%, respectively; while the replacement ratio of manure was higher than 30%, the yield did not significantly increase. Net economic benefit of wheat production was influenced by the replacement ratio of manure and the type of substituted manure. The replacement ratio of manure was less than 30%, and the net economic benefit showed no significant diffidence; while the replacement ratio of manure was higher than 45%, net economic benefits decrease by 18%, 68% when using cow manure and commercial manure as substituting fertilizer. Substituting fertilizer by manure reduced NH₃ volatilization by 24% in whole wheat growing season, and decreased nitrate residue by 16% at wheat harvest stage, but increased N₂O emission by 32% in whole wheat growing season. Further analysis indicated that soil properties, manure types, climatic conditions, test duration, yield and fertilization level could regulate wheat yield of substituted manure. Compared with application of chemical fertilizer treatment, the grain yield in substituting fertilizer by manure increased by 4% when soil organic matter>15 g·kg ^-1, while there was no difference when soil organic matter<15 g·kg ^-1. Yield in substituting fertilizer by manure increased by 8% when soil pH<7, while there was no difference when soil pH>7. When chicken manure, pig manure and commercial organic manure was used as substituted manure, grain yield increased by 6%, 6% and 4%, respectively, while there was no difference when cow manure was considered as substituted manure. Substituting fertilizer by manure treatment significantly increased yield by 4% in the areas with annual precipitation >600 mm, but there was no difference in the areas with annual precipitation ≤600 mm. Substituting fertilizer by manure increased yield by 5% in areas with average annual air temperature>15℃, but there was no difference in the areas with average annual air temperature <15℃. The duration of the experiment, the different yield and fertilization levels could affect wheat yield of substituted manure. Compared with the application of chemical fertilizer treatment, the grain yield in substituting fertilizer by manure increased by 6% when duration of the experiment more than a decade, while there was no difference when duration of the experiment less than a decade. Yield in substituting fertilizer by manure increased by 4% when under the condition of high nitrogen application rate, while there was no difference when low nitrogen application rate. The substitution of manure at low yields significantly increased wheat yield by 9%, while the substitution of manure at medium and high yields no difference. 【Conclusion】 Substituting fertilizer by manure did not reduce wheat yield under the condition that the use of chemical nitrogen fertilizer was reduced by an average of 43%. Substituting fertilizer by manure had the potential to substantially reduce the amount of chemical N fertilizer and N loss while maintaining wheat yield, but did not increase economic income. It was very important for increasing wheat yield, protecting ecological environment and increasing economic income to adopt suitable manure types and ratio of substituting fertilizer by manure. The use of reasonable amount of chemical N fertilizer substitution and manure types had the potential to increase the yield of substituting fertilizer by manure in the areas of sufficient precipitation and high air temperature.

Key words: replacement ratio of manure, soil properties, climatic conditions, N₂O emissions, NH₃ volatilization, nitrate leaching, yield, economic benefits