秸秆和生物炭添加对关中地区玉米-小麦轮作农田温室气体排放的影响

Effects of Straw and Biochar Amendment on Greenhouse Gases Emission in Wheat-Maize Rotation Cropland in Guanzhong Area

为探讨玉米—小麦轮作农田秸秆和生物炭添加的固碳减排效应,以关中地区典型玉米—小麦轮作农田为研究区域,采用静态暗箱—气相色谱法监测了秸秆和生物炭添加后土壤CO2,CH4和N2O排放的动态变化。设常规施肥(N)、施基肥和添加4t/hm^2秸秆还田(NS)、施基肥和添加4t/hm^2生物炭(NB_(Clow))、施基肥和添加8t/hm^2生物炭(NB_(Chigh))和对照(CK)既不施肥也不施有机物料5个处理。结果表明:(1)与N处理相比,NS处理的农田土壤N2O排放总量没有显著变化,添加生物炭降低了土壤N2O年排放总量,NB_(Clow)和NB_(Chigh)处理分别降低了13.21%和23.75%。(2)与N处理相比,NS处理的农田土壤CO2年排放总量增加了44.07%,添加8t/hm^2生物炭降低了CO2年排放总量,NB_(Chigh)处理降低了9.94%。(3)与N处理相比,NS处理的CH4年排放总量增加了42.32%。NB_(_(Clow))和NB_(Chigh)处理CH4年排放总量分别增加了76.38%和73.23%。(4)秸秆还田和生物炭添加均提高了作物产量,与N处理相比,NS,NB_(Clow)和NB_(Chigh)处理的年产量分别提高了13.73%,20.37%和7.56%;NB_(Chigh)处理比NB_(Clow)处理年产量降低了10.64%;与N处理相比,NS,NB_(Clow)和NB_(Chigh)处理的小麦产量分别提高了22.36%,25.41%和14.06%;NS,NB_(Chigh)处理的玉米产量分别提高了5.40%和15.50%。(5)添加生物炭降低了净增温潜势,与N处理相比,NB_(Clow)和NB_(Chigh)处理分别降低了33.59,48.33t/hm^2,单位产量的净增温潜势分别降低了2.53,4.21t/t。综上所述,添加4t/hm^2生物炭更有利于玉米—小麦轮作农田系统的固碳减排和产量的提高。

In order to reveal the effects of straw and biochar amendment on greenhouse gases（GHG）emission and crop yield,the farmland ecosystem of maize-wheat rotation in Guanzhong Plain of China was taken as the study area.The annual GHG emissions（CO2,CH4,and N2O）from a wheat-maize rotation system with straw and biochar amendment were monitored using the static opaque chamber and gas chromatography technique.Five field treatments in the study including conventional fertilization（N）,fertilization and 4 t/hm-2 straw（NS）amendment,fertilization and 4 t/hm-2 biochar（NB（Clow））amendment,fertilization and 8 t/hm-2 biochar（NB（Chigh））amendment.CK was without straw,biochar and fertilizer.The results showed that：（1）compared with N treatment,annual N2O emission decreased by 13.21%and 23.75% under NB（Clow） and NB（Chigh）treatment,respectively,and no significant difference was observed under straw application;（2）compared with N treatment,annual CO2 emission increased by 44.06% under NS treatment,but decreased by 9.94%under NB（Chigh）treatment;（3）compared with N treatment,annual CH4 emission increased by 42.32%,76.38% and 73.23%,respectively,under NS,NB（Clow）and NB（Chigh） treatment;（4）yield increased by13.73%,20.37% and 7.56%,respectively,under NS,NB（Clow）and NB（Chigh）treatment as compared to N treatment,and decreased by 10.64% under NB（Chigh）treatment as compared to NB（Clow） treatment;（5）the NGWP decreased by 33.59 t/hm-2 and 48.33 t/hm-2,respectively,under NB（Clow）and NB（Chigh）treatment as compared to N treatment,and the NGHGI decreased by 2.53 t/t and 4.21 t/t,respectively,under NB（Clow） and NB（Chigh）treatment as compared to N treatment.In summary,it is concluded that biochar application of 4 t/hm-2 can be used as an effective management to carbon sequestration and increase crop yields under the wheat-maize rotation system in Guanzhong Area.