【摘要】 通过5年田间定位试验,研究了不同玉米秸秆还田方式对黑钙土土壤团聚体含量、稳定性和团聚体有机碳贡献率的影响。结果表明:与秸秆不还田(CK)比较,秸秆还田处理能显著提高土壤大团聚体(>250μm)含量、团聚体平均重量直径(MWD)和几何平均直径(GMD)(P<0.05)。秸秆轮耕还田(SRT)比秸秆覆盖还田(SCR)能更有利于土壤大团聚体形成,但2个处理的土壤团聚体稳定性之间差异不显著。秸秆轮耕还田与秸秆不还田相比较能显著增加土壤各粒级团聚体有机碳含量和大团聚体有机碳贡献率,同时,秸秆轮耕还田比秸秆覆盖还田更有利于提高>2 000μm粒径和<53μm粒径团聚体有机碳含量,以及250～2 000μm粒径团聚体有机碳贡献率。相关性分析表明,土壤有机碳含量与土壤团聚体稳定性及其碳库之间存在极显著的正相关关系。旋耕/深翻的轮耕还田模式促进了耕层土壤大团聚体形成和土壤结构稳定,显著提高土壤团聚体碳库和对土壤有机碳的贡献,为东北黑钙土区较适宜的玉米秸秆还田模式之一。更多还原

【Abstract】 A Five-year field experiment was conducted to study the size compositions and stability of soil aggregate and their soil organic carbon(SOC)contribution rates to total SOC in different maize straw returning treatments(without straw returning,CK;straw cover returning,SCR;straw rotational tillage returning,SRT).The results indicated that straw returning modes significantly increased the mass of macro-aggregates(>250μm),mean weight diameter(MWD)and geometric mean diameter(GMD),compared with CK(P <0.05).SRT had more significant effects on formation of soil macro-aggregates than SCR,but there was no obvious difference in stability of soil aggregate between SRT and SCR.SRT markedly enhanced SOC of every size aggregates and contribution rates of aggregates SOC,which were higher than SCR in SOC of>2 000μm and<53μm aggregates,contribution rates of 250～2 000μm aggregates SOC.There were significant positive correlations between the SOC and the stability and associated-C(P < 0.01)of aggregate.Straw rotational tillage(two years of rotary tillage plus one year of moldboard return)was more favorable for macroaggregates formation and soil structure stability,improving carbon pool of soil aggregate and their SOC contribution rates,which one of was the most appropriate rotational tillage pattern in Chernozem soil,northeast China.更多还原