秸秆/生物炭施用对关中地区小麦-玉米轮作系统净增温潜势影响的对比分析

Comparative Analysis on Effect of Wheat Straw and Its Biochar Amendment on Net Global Warming Potential Under Wheat-Maize Rotation Ecosystem in the Guanzhong Plain

为探讨秸秆、生物质炭施用对小麦-玉米轮作系统固碳减排效应,利用静态暗箱-气相色谱原位监测小麦-玉米轮作系统条件下秸秆、生物质炭施用对土壤CO_2、CH4和N_2O 3种温室气体排放、作物产量、土壤有机碳以及净增温潜势的影响.试验处理设置为:空白对照(CK)、常规施肥(F)、施肥并施用8 t·hm-2秸秆(FS)、施肥并施用8 t·hm-2生物质炭(FBlow)和施肥并施用16 t·hm-2生物质炭(FBhigh)共5个处理.结果表明:与F处理相比,FS、FBlow及FBhigh处理下小麦产量分别提高了30.9%、66.3%和36.6%;对于玉米产量而言,FS,CK及FBhigh处理下玉米产量分别降低了14.1%、18.0%和24.6%,但是FBlow处理下对玉米产量没有显著性的影响.与F处理相比,FS处理下土壤CO_2的年排放总量增加了60.2%,但是FBhigh处理下土壤CO_2的年排放总量减低了14.4%;生物质炭的施用降低了土壤N_2O的排放,与F处理相比,FBlow和FBhigh处理下分别减低了27.6%和38.7%,而秸秆的施用对N_2O的排放没有显著性的影响.总的来说,与F处理相比,FBlow和FBhigh处理下净增温潜势分别降低了24.13和58.44 t·hm-2,单位产量的净综合增温潜势分别降低了1.78和5.06 t·t-1.综上所述,对于小麦-玉米轮作体系而言,施用16 t·hm-2生物质炭可作为一种提高作物产量并降低净增温潜势的良好措施.

In order to compare the differences in carbon sequestration and greenhouse gas mitigation between straw and straw-derived biochar amendment, a field experiment was conducted with simultaneous measurement of carbon dioxide （CO2 ）, methane （CH4 ） and nitrous oxide （N2 O） emissions, crop yield, soil organic carbon （SOC） content and net global warming potential （NGWP） in a wheat-maize rotation cropping system from the loess plateau of China. Five treatments were included： control （no straw incorporation, no straw-derived biochar amendment and no fertilization, CK）, fertilization （no straw incorporation and no straw-derived biochar amendment, F）, straw with fertilization （wheat straw incorporated at 8 t·hm ^- 2 , FS）, low straw-derived biochar （8 t·hm ^- 2 ） with fertilization （FBlow） and high straw-derived biochar （16 t·hm^ - 2 ） with fertilization （FBhigh）. Wheat yield increased by 30. 9% , 66. 3% and 36. 6% under FS, FBlow and FBhigh treatment, as compared to the F treatment, respectively. However, maize yield decreased by 14. 1% , 18. 0% and 24. 6% under FS, CK and FBhigh treatment as compared to the F treatment, respectively. There was no significant difference between FBlow and F treatment. Annual CO2 emission increased by 60. 2% under FS treatment, but decreased by 14. 4% under FBhigh treatment as compared to the F treatment, respectively. Annual N2 O emission decreased by 27. 6% and 38. 7% under FBlow and FBhigh treatment as compared to the F treatment, respectively. However, no significant difference was observed under straw application. Overall, the NGWP decreased by 24. 13 and 58. 44 t·hm ^- 2 under FBlow and FBhigh treatment as compared to the F treatment, respectively. And the NGHGI decreased by 1. 78 and 5. 06 t·t^ - 1 under FBlow and FBhigh treatment as compared to the F treatment, respectively. In summary, we conclude that the fertilization with 16 t·hm ^-2 biochar amendment can be used as an effective management to improve the crop yield and reduce the net global warming potential under the wheat-maize rotation system.