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通过田间试验,在大豆和冬小麦生长季,进行常规翻耕(conventional tillage,T)、免耕(no-tillage with no straw cover,NT)、常规翻耕+秸秆(conventional tillage with straw cover,TS)、免耕+秸秆(no-till with straw cover,NTS)4种耕作措施处理,采用静态箱-气相色谱法测定土壤-作物系统CO_2和N_2O排放通量.结果表明:在大豆生长季,与T相比,NTS在开花-结荚期显著增加了CO_2累积排放量(P=0.045),增幅达27.9%;NT在鼓粒-成熟期显著降低了CO_2累积排放量(P=0.043),降幅达28.9%.与T相比,NT在鼓粒-成熟期的N_2O累积排放量降低了28.3%(P=0.042).在冬小麦生长季,与T相比,TS、NT在拔节-孕穗期使CO_2累积排放量降低了24.3%(P=0.032)和36.0%(P=0.041),在成熟期降低了26.8%(P=0.027)和33.1%(P=0.038).在返青期,NT、NTS、TS的N_2O累积排放量与T比较均没有明显差异,NTS比NT的N_2O累积排放量降低了42.0%(P=0.035).可见,保护性耕作措施对土壤-作物系统CO2排放的影响较大,对N2O排放的影响不明显.
Through field experiments, conventional tillage (T), no-tillage with no straw cover (NT), conventional tillage with straw cover (TS) , No-till with straw (NTS), and static box-gas chromatography (GC-MS) was used to determine the CO_2 and N_2O fluxes of soil-crop system.The results showed that in the soybean growing season, NTS significantly increased the cumulative CO 2 emissions (P = 0.045) at the flowering and podding stages, an increase of 27.9%, while NT significantly reduced the cumulative CO 2 emissions (-0.043) at the puffing and maturing stages (P = 0.043) 28.9% .Compared with T, N 2 O 2 emission decreased by 28.3% (P = 0.042) in the grain-maturity stage of NT at NT stage.In the winter wheat growing season, Cumulative emissions were reduced by 24.3% (P = 0.032) and 36.0% (P = 0.041) and by 26.8% (P = 0.027) and 33.1% (P = 0.038) during maturation. There was no significant difference between TS cumulative emission of N 2 O and T, and NTS decreased by 42.0% (P = 0.035) compared with NT. It can be seen that the effect of conservation tillage on soil-crop system CO2 emissions A greater impact, the impact on N2O emissions is not obvious.