不同土地利用方式下表层土壤大团聚体特征

Characteristics of surface soil macro aggregates under different land use patterns

土壤大团聚体含量能表征土壤结构稳定性,反映土壤结构变化趋势。本研究在辽河干流中下游流域主要沙化区分析湿地、林地、农田和草地4种土地利用方式对0-20cm土层土壤大团聚体(>0.25 mm)含量和稳定性的影响,及各粒径大团聚体的空间异质性,并进行空间插值模拟其分布。结果显示,农田土壤团聚体破坏率最大,达到46.98%,林地最小,为26.36%;依据土壤水稳性大团聚体含量、团聚体颗粒平均重量直径和几何平均直径,评价土壤结构稳定性强弱为湿地>林地>农田>草地;4种土地利用导致土壤大团聚体稳定性差异显著(P<0.05),湿地和草地之间的差异性最显著;湿地土壤结构相对最好,其次是林地和农田,草地相对最差。本研究结果可为辽河干流流域土地沙化程度评价及分区治理提供参考依据。

The content of soil aggregates can be used to characterize the stability of soil structure and reflect the change trend of soil quality. In this study, the effects of 4 kinds of land use, namely, wetland, woodland, farmland, and grassland, on soil aggregate content and stability were analysed in the 0--20 cm soil layer, and the spatial heterogeneity of large particle size aggregates was analysed to simulate the distribution by spatial in- terpolation. The results showed that the destruction rate of farmland soil aggregates was the maximum at 46.98~/oo, but that of woodland was the minimum at 26.36~. On the basis of the content of soil water stable ag gregate, and mean weight diameter and geometric mean diameter of aggregate particles, the strength of soil structure stability was found to be wetland ~ woodland 〉 farmland ~ grassland; all 4 kinds of land use resul- ted in significant differences in soil aggregate stability （P^0.05）, and the difference between the wetland and grassland was the most significant. Wetland soil structure was the best, followed by woodland and farmland; grassland showed the least stable soil structure. The results of this study can provide a reference basis for the e- valuation of desertification degree and zoning management in the Liaohe River basin.