年内轮耕对小麦-玉米两熟农田土壤水稳性团聚体碳、氮分布的影响

摘要

在华北平原小麦-玉米两熟区，设置6种年内轮耕模式，即小麦季免耕玉米季免耕（ WZ-MZ）、小麦季免耕玉米季深松（ WZ-MS）、小麦季深松玉米季免耕（ WS-MZ）、小麦季深松玉米季深松（ WS-MS）、小麦季翻耕玉米季免耕（ WC-MZ）、小麦季翻耕玉米季深松（ WC-MS），探讨年内轮耕模式对土壤水稳性团聚体碳、氮分布的影响。结果表明，MS的年内轮耕模式比MZ有利于0～40 cm土层微团聚体聚成更大粒级的团聚体和保护大团聚体免受破坏；无论玉米季免耕还是深松条件下，与WZ、WC相比， WS能提高10～40 cm土层＞0．25 mm粒级的大团聚体含量；WZ和WS比WC能显著提高土壤表层有机碳及全氮，使更多的碳、氮在土壤表层聚集；MS比MZ能降低0～10 cm和提高10～40 cm土层团聚体中有机碳及全氮含量；WZ能显著提高土壤0～10 cm土壤团聚体中C/N；无论小麦季采用哪种耕作方式，MS比MZ能降低0～10 cm和提高10～40 cm土层团聚体中C/N。%Six rotation tillage modes were used to study the effects of different rotation tillage modes with-in a year on the distributions of organic carbon and nitrogen in soil water -stable aggregates in wheat -maize double-cropping system in North China Plain .The effects of wheat and maize both no -tillage ( WZ-MZ) , wheat no-tillage and maize subsoiling (WZ-MS), wheat subsoiling and maize no -tillage (WS-MZ), wheat and maize both subsoiling ( WS-MS) , wheat conventional tillage and maize no -tillage ( WC-MZ) , wheat conventional tillage and maize subsoiling ( WC-MS) were compared under the same sowing date and seedling densities .The results showed that the rotation tillage mode of MS within a year was better for soil mi-cro aggregate gathering into larger aggregates in 0~40 cm soil layer and protecting large aggregates from dam-age than MZ.Under maize no -tillage or subsoiling condition , compared with WZ and WC , WS could im-prove the content of large aggregate (>0.25 mm) in 10~40 cm soil layer.Compared with WC, WZ and WS could significantly increase the soil organic carbon and total nitrogen content in surface soil and make more carbon and nitrogen gathering in surface soil .MS could reduce the soil organic carbon and total nitrogen con-tent in the aggregates in 0~10 cm soil layer and raise those in 10~40 cm soil layer than MZ .WZ could sig-nificantly increase the C/N in the aggregates in 0~10 cm soil layer .No matter what tillage mode of wheat , MS could reduce the C/N in the aggregates in 0~10 cm soil layer and raise that in 10~40 cm soil layer than MZ.