秸秆生物炭对玉米农田温室气体排放的影响

通过大田试验,采用静态暗箱-气象色谱法研究玉米农田不施生物炭(C0),施生物炭分别为15 t/hm2(C15)、30 t/hm2(C30)和45 t/hm2(C45)后温室气体(CO_2、CH_4和N_2O)的排放特征,并估算CH_4和N_2O的综合增温潜势(GWP)及排放强度(GHGI)。结果表明:添加生物炭显著降低CO_2和N_2O的季节累积排放总量,与C0处理相比,CO_2最大降幅为24.6%(C15),N_2O最大降幅为110.35%(C45),且其随着生物炭施用量的增加而降低;CH_4的季节累积排放总量由小到大依次为:C15、C30、C0、C45,其中,C15处理较C0处理降低幅度最大为259.62%,添加生物炭同时也降低CH_4和N_2O的综合增温潜势(GWP)及排放强度(GHGI),处理C15、C30和C45的GWP值较对照C0分别降低88.2%、123.2%和109.9%,GHGI分别降低88.86%、121.60%和100.03%。施用适量的生物炭可以有效增加玉米产量,处理C15、C30和C45的增幅分别为6.28%、7.27%和1.69%。处理C30显著降低CH_4和N_2O的综合增温潜势及其排放强度,并且产量的增幅最大。因此,在当前玉米农田管理措施下,生物炭施用量为30 t/hm2时可实现玉米增产和固碳减排的目标。

Impacts of Straw Biochar on Emission of Greenhouse Gas in Maize Field

A field experiment was conducted by using the static chamber-gas chromatography method to analyze the emission behavior of greenhouse gas (CO2, CH4 and N2O), and estimate the global warming potentials (GWP) of CH4 and N2O and the greenhouse gas intensity (GHGI) through different straw biochar application treatments in a maize field, including none biochar application (C0), biochar application rate of 15t/hm2 (C15), 30t/hm2 (C30) and 45t/hm2 (C45). Results showed that biochar application can significantly decrease the seasonal emissions of CO2 and N2O. The emissions of CO2 and N2O were decreased with the increase of biochar application rate, and the maximum decreases of CO2 and N2O emission were 24.6% (C15) and 110.35% (C45), respectively, compared with those of C0. The seasonal CH4 emission followed a decreasing order of C15, C30, C0 and C45, in which the maximum decrease of CH4 emission for C15 was 259.62% compared with that of C0. Biochar application can also decrease the comprehensive temperature increasing potentials (GWP) and the emission intensity (GHGI) of CH4 and N2O. The GWP of C15, C30 and C45 were reduced by 88.2%, 123.2% and 109.9%, respectively, and the GHGI were reduced by 88.86%, 121.60% and 100.03%, respectively, compared with those of C0. In addition, biochar application was able to increase maize yield. Compared with that of C0, the maize yield increases were 6.28%, 7.27% and 1.69% for C15, C30 and C45, respectively. The experiment demonstrated that C30 reached the most decrease of GWP and GHGI and increase of maize yield. Therefore, biochar application with a rate of 30t/hm2 can achieve the purposes of yield increase, carbon fixation and emission reduction under the current maize filed management measures.