生物炭施用量对紫色水稻土温室气体排放的影响

Effects of Biochar Application Rates on Greenhouse Gas Emissions in the Purple Paddy Soil

为探究生物炭施用量对紫色水稻土温室气体排放的影响,通过盆栽试验,采用静态暗箱/气相色谱法,研究了不施肥对照(CK)、常规施肥(NPK)、10 t·hm-2生物炭+NPK(LBC)、20 t·hm-2生物炭+NPK(MBC)、40 t·hm^(-2)生物炭+NPK(HBC)这5种处理下温室气体的排放规律.结果表明:(1)生物炭施用显著降低了土壤CH_4排放通量,其排放通量大小顺序为:NPK>CK>LBC>MBC>HBC,各处理CH_4排放通量均呈单峰型曲线,峰值主要集中在水稻的生长后期,整个观测期CH_4的排放通量在-0.05~47.34 mg·( m^2·h)^(-1)之间;各处理CO_2排放通量变化较复杂,介于32.95~1 350.88mg·( m^2·h)^(-1)之间,除LBC和MBC处理呈双峰型曲线外,其余处理均呈单峰型,不同生物炭施用量处理均延后了CO_2排放通量峰值出现的时间;N_2O的排放通量在-309.39~895.48μg·( m^2·h)^(-1)之间,除LBC处理呈双峰型曲线变化外,其余处理均呈单峰型曲线;(2)与空白对照处理相比,生物炭处理均可显著降低CH_4的累积排放量,而促进了CO_2和N_2O累积排放量,CH_4、CO_2和N_2O的平均累积排放量从大到小分别为CK>LBC>MBC>HBC处理、LBC>MBC>HBC>CK处理和HBC>MBC≈LBC>CK处理;与常规施肥处理相比,不同施用量生物炭添加均可显著降低CH_4和CO_2的排放,且生物炭添加量越多,对CH_4和CO_2排放的减缓作用越明显,但是对N_2O排放的抑制作用尚不明显;(3)在100 a时间尺度上各生物炭处理可显著降低温室气体的综合增温潜势,表明生物炭配施化肥是一种有效的减排措施.

In order to explore the effects of different amounts of biochar applied in purple paddy soil on greenhouse gas（ GHG）emissions,potted experiments using a static opaque chamber and gas chromatography method were used to study the regulations and influences of biochar on soil greenhouse gas emission using five treatments： no fertilizer（ CK）,conventional fertilization（ NPK）,10 t·hm-2 biochar ＋ NPK（ LBC）,20 t·hm^（-2） biochar ＋ NPK（ MBC）,and 40 t·hm-2 biochar ＋ NPK（ HBC）.（1） Soil CH4 emission flux reduced significantly with all biochar application treatments; the emission flux followed the order,from large to small,of NPK CK LBC MBC HBC. The CH4 emission flux of each treatment showed a single peak curve,and the peak value was mainly concentrated in the late growth stage of the paddy cropland. During the entire observation period,the emission flux of CH4 was between-0. 05 mg·（ m^2·h）^（-1） and 47. 34 mg·（ m^2·h）^（-1）. The CO2 emission flux of each treatment was complicated and ranged from 32. 95 mg·（ m^2·h）^（-1） to 1 350. 88 mg·（ m^2·h）^（-1）. The CO2 emission flux of the LBC and MBC treatments showed bimodal curves,and the CO2 emission flux of other treatments showed single peak curves. In addition,all biochar treatments delayed the peak time of the CO2 emission flux. The N2O emission flux of each treatment ranged from -309. 39 to 895. 48 μg·（ m^2·h）^（-1）,and the N2O emission flux of the LBC treatment showed a bimodal curve,while other treatments showed single peak curves.（2） Compared with the CK treatment,biochar treatment can significantly reduce the cumulative emissions of CH4 and promote the cumulative emissions of CO2 and N2O. The average amount of CH4 cumulative emissions followed the order CK LBC MBC HBC,while the average amount of CO2 cumulative emissions followed LBC MBC HBC CK,and the average amount of N2O cumulative emissions followed HBC MBC≈LBC CK.Compared with conventional fertilization treatment,different application rates of biochar addition significantly reduced CH4 and CO2 emissions. As more biochar was added,CH4 and CO2 cumulative emissions were lower. Although the regulation of N2O cumulative emissions on biochar addition was not obvious,the application of nitrogen fertilizer could promote the emission flux of N2O to some extent.（3） Over the time scale of 100 years,the integrated global warming potentials（ GWP） of CH4 and N2O emission under different biochar treatment were decreased significantly,indicating that biochar combined with chemical fertilizer is an effective GHG emission reduction measure.