不同土地利用方式土壤团聚体组成及几种团聚体稳定性指标的比较

为分析比较不同土地利用方式以及种植年限土壤团聚体质量，获得较灵敏的团聚体状况指标与研究方法，揭示人为活动对土壤质量的作用与影响，以关中地区不同种植年限的菜园土壤和果园土壤为研究对象，经干筛法测定团聚体的组成状况后分别用平均质量直径（MWD）、几何均重直径（GMD）、分形维数D以及矩法参数为指标，分析菜园土壤和果园土壤在系列时间的振动筛分过程中团聚体组成变异特征，结果表明：用MWD和GMD作为团聚状况指标，只有在适宜的振动筛分时间范围内才能基本反映各种性状土壤的团聚水平差异；用分形维数作为指标，表征各类土壤的团聚水平的可信性值得商榷；用矩法的理论和其中的偏倚系数Cs能够较为灵敏地表征各类土壤的团聚水平。同时，研究发现菜园土壤和果园土壤的团聚化水平均有随着种植年限的增加有先提高后降低的趋势。研究得出了矩法的偏倚系数能够更清楚地区分各土壤之间的团聚水平，为评价土壤团聚水平提供更为灵敏的指标。

Comparative study on composition of soil aggregates with different land use patterns and several kinds of soil aggregate stability index

To analyze and compare the quality of soil aggregate under various conditions, and find more sensitive status index and research method of the aggregation, and reveal the effect and influence of human activities on soil quality, an experiment on vegetable garden soil and the orchard soil with different planting histories was conducted. Mean weight diameter (MWD), geometric mean diameter (GMD), dimension and moment method parameter were used to analyze the characteristics of aggregates composition variation of the two kinds of soil in the process of vibration screening. The results showed that: MWD and GMD as aggregate status index could basically reflect the difference of the soil aggregate levels only in the appropriate scope of vibration screening time. The credibility of using dimension for index to display the level of soil aggregate was questionable. Moment method parameter was more sensitive to characterize the level of soil aggregate. At the same time, the level of soil aggregate of both garden soil and orchard soil increased at first and then decreased with the increase of using term.