黄土高原丘陵沟壑区土地利用方式对土壤团聚体特征的影响

为研究黄土高原丘陵沟壑区复垦土地在不同利用方式下对土壤团聚体的影响,以陕西延安南泥湾沟壑区退化耕地整治复垦后,5种不同的土地利用方式,分别为林地(F处理),水稻(R处理),玉米(M处理)、蔬菜(V处理)及荒地(CK处理)。测定分析干筛法和湿筛法0—40cm土层土壤0.25mm团聚体分布、平均重量直径(MWD)、几何平均直径(GMD)、团聚体破坏率(PAD)和分形维数(D)。结果表明:(1)各处理在0—40cm各土层土壤团聚体数量及大小均显著优于CK处理,各处理干筛下0—40cm土层0.25mm团聚体含量(DR0.25)和湿筛下该团聚体含量(WR0.25)随着土壤土层深度的增加呈现相反的趋势;(2)干筛法和湿筛法0—40cm土层各处理土壤平均重量直径(MWD)和几何平均直径(GMD)的平均值大小顺序均呈现F处理R处理M处理V处理CK处理,F处理和R处理对增加土壤团聚体较其它处理效果显著;(3)湿筛法分析表明,各处理土壤团聚体破坏率(PAD)在0—40cm土层内均表现出近似"Z"字形趋势,各处理显著低于CK;(4)各处理的分形维数(D)在0—40cm土层平均值大小顺序为F处理R处理M处理V处理CK处理。土壤分形维数(D)与干筛法和湿筛法下0—40cm土层0.25mm团聚体含量之间存在良好的线性关系,分别为R2=0.73和R2=0.80。林地和水稻田利用方式可有效提高土壤团聚体数量和质量,增加土壤稳定性和改善土壤结构。

Effects of Land Use Types on Soil Aggregate Characteristics in Hilly-gully Region of Loess Plateau

The effects of reclaimed land on soil aggregates under different land use patterns in the hilly-gully regions of Loess Plateau were studied to provide the scientific basis for improving soil stability and productive performance of reclaimed land. Five different land use types after reclamation of degraded cultivated land, included forestland (F treatment), rice (R treatment), maize (M treatment), vegetable (V treatment) and wasteland (CK treatment), were studied in the Nanniwan gully area of Yan''an, Shaanxi Province. The mean weight diameter (WMD), geometric mean diameter (GMD), aggregate processing damage rate (PAD) and fractal dimension (D) of >0.25 mm aggregates in wet sieve method and dry sieve of 0 ~ 40 cm soil layer soil were measured. The results showed that: (1)The number and size of soil aggregates in 0-40 cm soil layer were significantly better than those in CK treatment. The content of >0.25 mm aggregate (DR0.25) and (WR0.25) in 0-40 cm soil layer showed the opposite trend with the increase of soil depth. (2)The order of mean weight diameter (MWD) and geometric mean diameter (GMD) of soil treated by dry sieve method and wet sieve method was F treatment>R treatment>M treatment>V treatment>CK treatment, F treatment and R treatment on soil aggregates increased significantly than other treatments. (3)The results of wet sieve analysis showed that the PAD of soil aggregates in 0-40 cm soil layer showed similar Z-shaped trend, and the treatments were significantly lower than CK. (4)The fractal dimension (D) of each treatment was in the order of F treatment