【摘要】 土壤团聚体与土壤侵蚀和径流密切相关,本试验用Le Bissonnais法中的快速处理测定黄土丘陵区纸坊沟流域土壤水稳性团聚体含量,计算团聚体平均质量直径(MWD)、几何平均直径(GMD)和质量分形维数(D),比较几种水稳性团聚体指标之间的相关性,确定植被类型对土壤水稳性团聚体含量的影响。结果表明,大于0.2 mm的土壤团聚体含量在1978年油松林地的0~5 cm层最大,为54.95%,在1990年刺槐林地和荒地的20~40 cm层最小,为3.20%;MWD(mm)和GMD(mm)在1978年油松林地的0~5 cm层最大,分别为1.66和0.46,在荒地的20~40cm层最小,分别为0.09和0.05;表层(0~5 cm)土壤D在2.71~2.84之间,表下层在2.74~2.91之间。土壤有机质与D,MWD,GMD和>0.2 mm显著相关,表明增加土壤有机质含量有利于土壤团聚体形成和水稳定性提高。D,MWD,GMD和>0.2 mm都可用于表征土壤团聚体水稳定性,作为土壤抗侵蚀性指标。更多还原

【Abstract】 Soil aggregate is crucial to soil erosion and runoff.The fast wetting of Le Bissonnais method was used to measure the content of soil water stable aggregate and samples were collected from Zhifanggou catchment of the Loess hilly-gully region.The mean weight diameter(MWD),geometric mean diameter(GMD) and mass fractal dimension(D) of soil aggregates were calculated and correlations among these indexes were analyzed.The effects of vegetation types on the content of soil water stable aggregates were studied.The results indicate that the biggest content of >0.2 mm soil aggregate is 54.95% in the 0～5cm of Chinese pine forest restored in 1978 year land and the smallest is 3.20% in the 20～40 cm of black locust forest land restored in 1990 year and abandoned land;The biggest of MWD(mm) and GMD(mm) are 1.66 and 0.46 respectively in the 0～5 cm of Chinese pine forest land restored in 1978 year and the smallest of them are 0.09 and 0.05 respectively in the 20～40 cm of abandoned land.D of topsoil(0～5 cm) and subsoil(5～20 cm) are 2.71～2.84 and 2.74～2.91 respectively.>0.2 mm,MWD,GMD and D correlate significantly with soil organic matter,which indicate that increasing the content of soil organic matter can improve soil aggregate formation and soil aggregate water stability.D,MWD,GMD and >0.2 mm can indicate soil aggregate water stability and are the indicators of the soil anti-erodibility.更多还原