纳版河流域土地利用方式对土壤水稳性团聚体的影响

Effects of Land Use Types on Soil Water-stable Aggregates in Naban River Watershed

土壤团聚体稳定性是土壤结构的关键性指标，是土壤环境、管理实践和土地利用方式相互作用的结果。为了探讨纳版河流域自然林转变为耕地以及不同种植年限橡胶林之后对土壤水稳性团聚体分布以及土壤团聚体水稳性的影响，研究了自然林、耕地（玉米地和水稻田）以及不同种植年限橡胶林土壤。结果显示：较之自然林，玉米地〉5mm以及5～2mm土壤水稳性团聚体质量分数分别显著（P〈0．05）下降了91．46％和73．37％，水稻田5～2mm土壤水稳性团聚体质量分数显著下降了63．73％；一年、五年以及十年橡胶林〉5mm土壤水稳性团聚体质量分数分别显著下降了44．66％、65．00％以及59．47％，5。2mm土壤水稳性团聚体质量分数分别显著下降了56．21％、43．16％以及34．34％；〉5mm、5～2mm以及2～1mm土壤水稳性团聚体质量分数随着橡胶种植年限的延长而增大。与自然林相比较，玉米地〉0．25mm土壤水稳性团聚体质量分数、MWD以及GMD均显著下降；一年、五年以及十年橡胶林〉0．25mm土壤水稳性团聚体质量分数、MWD、GMD均显著降低。相关分析表明：〉0．25mm土壤水稳性团聚体含量、MWD以及GMD与〉5mm以及5～2mm土壤水稳性团聚体含量之间均表现出极显著（P〈0．01）正相关关系。

Soil aggregates stability which could be influenced by soil environment, soil management practices and land use type can be used as an indicator of soil structural quality. The objective of this study was to evaluate the impact of conversion from natural forest to farmland （cornfield and rice-paddy field） and rubber plantation of different cultivating ages on the distribution characteristics of soil water-stable aggregates and water stability of soil aggregates in Naban river watershed. It was found that the distribution features of 〉 5 mm and 5 ~ 2 mm soil water-stable aggregates were significantly influenced after converting natural to farming land and rubber plantation with different cultivating ages, as compared with that of natural forest, the contents of 〉 5 mm and 5 ~ 2 mm soil water-stable aggregates lowered significantly （P 〈 0.05） by 91.46% and 73.37% respectively under cornfields, the contents of 5 - 2 mm soil water-stable aggregates decreased significantly by 63.73% under rice-paddy field, the contents of 〉 5 mm soil water-stable aggregates lowered significantly （P 〈 0.05） by 44.66%, 65.00% and 59.47% respectively and that of 5 2 mm soil water-stable aggregates decreased significantly （P 〈 0.05） by 56.21%, 43.16% and 34.34% respectively under rubber plantation converted from natural forest for one, five and ten years respectively. As compared with that of natural forest, the contents of 〉 0.25 mm soil water-stable aggregates, MWD and GMD lowered significantly （P 〈 0.05） under cornfields and the contents of 〉 0.25 mm soil water-stable aggregates, MWD and GMD decreased significantly under rubber plantation which had been converted from natural forest for one, five and ten years respectively. Correlation analysis demonstrated that the contents of 〉 0.25 mm soil water s extremely significantly （P 〈 0.01） and positively related to the contents of 〉 table aggregates, MWD and GMD were 5 mm and 5 - 2 mm soil water-stable aggregates.