农业废弃物还田对黑土温室气体排放及全球增温潜势的影响

【目的】研究牛粪、鸡粪、玉米秸秆与化肥配施还田,对黑土温室气体排放及全球增温潜势的影响。【方法】采用静态箱法,试验共设5个处理,分别为:空白对照,单施化肥,牛粪还田配施50%化肥氮(化肥中氮的质量分数为肥料中总氮量的50%),鸡粪还田配施50%化肥氮,秸秆还田配施90%化肥氮。除对照外各处理总施氮量为240kg·hm~(-2)。【结果】各处理中秸秆还田处理的CO_2平均排放通量及总排放量最高,分别达388.96 mg·m~(-2)·h-1和14 718.97 kg·hm~(-2),且追施氮肥明显增加CO_2的排放;单施化肥处理CH_4平均吸收通量及总吸收量最高,分别达0.042 mg·m~(-2)·h-1和1.36 kg·hm~(-2);单施化肥处理N_2O平均排放通量及总排放量最高,分别达0.153 mg·m~(-2)·h-1和5.75 kg·hm~(-2)。秸秆还田处理的全球增温潜势显著高于其他处理,牛粪还田处理较单施化肥处理全球增温潜势降低,但差异不显著。【结论】秸秆覆盖会增加黑土中的CO_2的排放,旱田土壤是大气中CH_4的重要吸收汇,有机无机肥配施对比单施化肥能减少土壤中N_2O的排放,各农业废弃物还田处理对大气变暖贡献程度不同。

Effects of agricultural wastes on greenhouse gas emission and global warming potential in black soil

[Objective] To study the effects of cow dung, chicken manure, and corn straw combined with chemical fertilizers on greenhouse gas emission and global warming potential.[Method] We used the static chamber technique and set up five treatments including control, chemical fertilizers only, cow dung plus chemical fertilizers containing 50% nitrogen of the total nitrogen in the treatment, chicken manure plus chemical fertilizers with 50% nitrogen, and straw plus chemical fertilizers with 90% nitrogen. Totally 240 kg·hm^-2 nitrogen was applied in each treatment except for control.[Result] Among all treatments, the straw treatment resulted in the highest average emission flux and average total emission of CO₂, being 388.96 mg·m^-2·h^-1 and 14 718.97 kg·hm^-2 respectively. Nitrogen topdressing evidently promoted CO₂ emission. The treatment of chemical fertilizers only resulted in the highest average absorption flux and average total absorption of CH₄, being 0.042 mg·m^-2·h^-1 and 1.36 kg·hm^-2 respectively, and resulted in the highest average emission flux and average total emission of N₂ O, being 0.153 mg·m^-2·h^-1 and 5.75 kg·hm^-2 respectively. The global warming potential in the straw treatment was significantly higher than those in other treatments. The global warming potential in the cow dung treatment was lower than that in the treatment of chemical fertilizers only, yet the difference was not significant.[Conclusion] Straw coverage can increase CO₂ emission in black soil. Upland soil is an important sink of CH₄ in the air. Compared with chemical fertilizers only, organic manure combined with inorganic fertilizer can reduce N₂O releasing. The contributions of different agricultural wastes to atmospheric warming vary in degree.