晋北丘陵风沙区不同植被恢复模式的水土保持效应

通过对山西右玉贾家窑阳坡退耕还林约20年后的4种植被恢复模式(自然恢复草地、油松林、柠条灌丛和油松—柠条林)土壤水分、理化性质、径流量和侵蚀量的测定,探讨了不同植被恢复模式的水土保持效应。结果表明:(1)4种植被恢复模式0—100cm土层土壤平均含水量无显著差异,油松林和自然恢复草地的土壤容重高于油松—柠条林和柠条灌丛,土壤总孔隙度的变化趋势与容重相反;(2)4种植被恢复模式0—20cm土层土壤粒度组成、pH、有机质、铵态氮和速效磷无显著差异,硝态氮和速效钾差异明显(P0.05);(3)4种植被恢复模式径流量没有明显差异,但土壤侵蚀量自然恢复草地和油松林显著高于柠条灌丛和油松—柠条林(P0.05);(4)覆盖度相似条件下,根系密度、近地表植被盖度和枯枝落叶层厚度是影响林草植被水土保持效应的主要因素。

Effects of Different Revegetation Patterns on Soil and Water Conservation in Sandy-hilly Region of Northern Shanxi Province

This study investigated soil and water conservation effect of different revegetation patterns in sandy-hilly region of northern Shanxi Province. The characteristics of soil water content, physical and chemical properties, runoff volume and soil erosion of four revegetation patterns plots which have been grown for about twenty years at sunny slope in Jiajiayao watershed in Youyu County, were analyzed. Those revegetation patterns included naturally colonized herbaceous plants, Pinus tabuliformis plantation, Caragana korshinskii plantation, and Pinus tabuliformis-Caragana korshinskii plantation. The results showed that:(1) There was no significant difference in soil water content in 0-100 cm depth. Soil bulk density of naturally colonized herbaceous plants and Pinus tabuliformis plantation were higher than those of Pinus tabuliformis-Caragana korshinskii plantation and Caragana korshinskii plantation, while the trends of soil total porosity were opposite to those of bulk density. (2) There were no significant differences in soil granularity distribution, pH, organic matter, ammonium nitrogen and available phosphorus in 0-20 cm depth of the four revegetation patterns, while the differences of nitrate nitrogen and available potassium were significant (P<0.05). (3) Revegetation patterns had significant differences on soil erosion,but no effects on runoff (P<0.05). The soil erosion of naturally colonized herbaceous plants and Pinus tabuliformis plantation were significantly higher than those of Caragana korshinskii plantation and Pinus tabuliformis-Caragana korshinskii plantation (P<0.05). (4) If coverage was similar, root density, near surface vegetation coverage and leaf litter thickness were the main factors affecting soil and water conservation effect of forest-grass vegetation.