通过测定土壤水稳性团聚体、总孔隙度、容重等物理性质,对延安梁峁山丘四种不同土地利用方式对土壤水稳性团聚体和总孔隙度的影响作了定量分析。结果表明,不同土地利用方式对土壤水稳性团聚体和总孔隙度的改善作用的大小顺序为草地>有林地>灌木林地>耕地。通过进一步分析四种土地利用方式下,土壤中直径≤1mm有效根根量的分布特征,发现不同土地利用方式下的土壤中,有效根根量的差异是造成这种不同影响的重要原因之一。

Based on the measuement of soil water-stable aggregate, total porosity, bulk density and other soil physical property parmeters, a quantitaive stduy of the effect of four different land use in Yanan city on the soil water-stable aggregate and the total porosity was made. The result showed that the sequence of the improvement of different land use to soil water-stable aggregate and total  porosity is natural grass land ＞ forest land ＞ shrub land ＞ cropland. By further measuring the soil roots parameters under four different land use, we found that the difference of effective roots (φ≤ 1mm) mass in the soil under different land use is one of important reasons of this difference.