不同覆盖模式对樱桃园土壤团聚体及碳氮的影响

Effects of Different Coverage Modes on Aggregates and Carbon and Nitrogen of Soil in Cherry Orchard

为探究不同覆盖模式对土壤团聚体及其碳氮的影响,以新津县樱桃园土壤为研究对象,采用定位试验,设置清耕(CK)、自然生草覆盖(NGC)、野豌豆覆盖(VC)和地布覆盖(GCM)4个处理,对土壤团聚体分布、大团聚体含量(R_(0.25))、平均重量直径(MWD)、几何平均直径(GMD)、团聚体破坏率(PAD)和不稳定团粒指数(E_(lt))及水稳性团聚体有机碳、全氮进行了测定与分析。结果表明:自然生草覆盖、野豌豆覆盖、地布覆盖和清耕在0—10 cm和10—20 cm土层的机械稳定性团聚体分布均以>5 mm团聚体含量最高,而水稳性团聚体分布以>5 mm和5~2 mm含量较高。在两个土层中,自然生草覆盖、野豌豆覆盖和地布覆盖与清耕相比,均提高了R_(0.25),MWD,GMD,降低了PAD和E_(lt),同时提高了水稳性团聚体有机碳、全氮含量。有机碳提升效果以自然生草覆盖处理最好,而全氮提升效果以野豌豆覆盖处理最好。综上,覆盖处理能够提高土壤团聚体稳定性以及水稳性团聚体有机碳、全氮含量,改善土壤质量。

In order to research the effects of different coverage modes on soil aggregates and carbon and nitrogen,the soil samples in the cherry orchard were taken in Xinjin County,and positioning experiment was adopted.Four treatments such as clean tillage(CK),natural grass coverage(NGC),vetch coverage(VC)and ground cloth coverage(GCM)were set up.Distribution of soil aggregates,large aggregates content(R_(0.25)),mean weight diameter(MWD),geometric mean diameter(GMD),percentage of aggregate destruction(PAD)and unstable aggregate index(E_(lt)),as well as organic carbon and total nitrogen in water-stable aggregates were tested and analyzed.The results showed that:contents of>5 mm mechanically stable aggregates in the 0—10 cm and 10—20 cm soil layers of natural grass coverage,vetch coverage,ground cloth coverage and clean tillage are the highest,while the contents of>5 mm and 5~2 mm water-stable aggregates are higher;in the two soil layers,compared with clean tillage,natural grass coverage,vetch coverage and ground cloth coverage increase R_(0.25),MWD,GMD and decrease PAD and E_(lt),increase the organic carbon and total nitrogen contents in water-stable aggregates;the best result of organic carbon improvement was natural grass coverage,the best result of total nitrogen improvement was vetch coverage.In summary,coverage treatments can increase the stability of soil aggregates,the organic carbon and total nitrogen contents of water-stable aggregates,as well as improve soil quality.