东北丘陵漫岗区坡耕地土壤抗蚀性研究

采用室内分析与野外试验测定相结合的方法,对研究区坡耕地土壤理化性状和土壤崩解速率进行了分析,并采用EPIC(土壤侵蚀和生产力影响估算)模型计算了土壤可蚀性因子K值,研究了东北丘陵漫岗区坡耕地抗蚀性分布特征。结果表明:(1)该区土壤容重的变化趋势为:0—5cm土层<20—25cm土层<40—45cm土层,坡下部<坡上部,7°<10°。土壤有机质含量变化趋势相反,中值粒径无明显变化规律。(2)土壤崩解速率随土层深度增加而逐渐增大,它与土壤容重和有机质相关性较好。容重越小,有机质含量越高,崩解速率越小。(3)土壤崩解速率随坡度和坡位变化规律一般表现为:坡上部>坡下部,7°<10°。(4)该区坡耕地土壤可蚀性K值处于0.20～0.40之间,土壤抗蚀性能较弱,应加强土壤抗侵蚀研究及水土流失方面的防治工作。

Anti-erodibility of Sloping Land Soil in Upland Region of Northeast China

With indoor experiment and field test,soil physical and chemical properties,soil disintegration rate and related influential factors of sloping land were determined.The formula calculation method of EPIC(erosion productivity impact calculator)was applied to investigate the erodibility factor K of the soil in sloping lands in northeastern upland region of China.The results indicate that soil bulk density increased in an ascending order of soil depth as 0—5cm<20—25cm<40—45cm.The soil of lower slope had smaller bulk density than that of upper slope.Similarly,the soil from gentle slope(7°)had smaller bulk density than that from steeper slope(10°).The organic matter contents showed an exactly opposite trend to bulk density.The median diameter of grain sizes did not show clear trend.The soil disintegration rates gradually increased with soil depth and correlated closely with soil bulk densities and organic matter contents:soil disintegration rate decreased with increase of organic matter content and decrease of soil bulk density.The soil from upper slope often had higher soil disintegration rate than that from lower slope,and the soil from gentle slope(7°)had smaller soil disintegration rate than that from steeper slope(10°).The calculated soil erodibility Kvaried between 0.20～0.40,indicating weak anti-erodibility.Therefore,water and soil conservation should be strengthened in the research area.