三峡库区森林土壤大孔隙特征及对饱和导水率的影响

发布时间：2018-11-09 09:51

【摘要】：土壤大孔隙是土体内孔径较大能优先传导水分的根孔、洞穴或裂隙,大孔隙内优先流的产生是土壤水分运动研究由均衡走向非均衡的标志。利用原状土柱的水分穿透试验,对三峡库区山地不同林型覆盖下土壤的大孔隙结构进行了研究,分析了温性阔叶林棕壤、针阔混交林黄棕壤、暖性针叶林黄壤及弃耕草地剖面内大孔隙的剖面分布特征及其对土壤饱和导水率的影响。结果表明:研究区内森林土壤的大孔隙当量孔径在0.3—3 mm之间,占土壤总体积的0.15%—4.72%。大孔隙中孔径0.3—0.6 mm的大孔隙密度最大,占大孔隙总数量的72.2%—90.4%;而孔径1 mm的孔隙仅占大孔隙总数量的1.26%—8.55%。土壤大孔隙密度和大孔隙面积比的顺序为:温性阔叶林棕壤针阔混交林黄棕壤针叶林黄壤弃耕坡地。各孔径段的大孔隙密度在不同样点均呈现A层-B层-C层逐渐减小的趋势,大孔隙密度与有机质含量呈显著正相关关系。土壤饱和导水率与不同孔径大孔隙的密度、面积比均成显著正相关关系,孔径1mm的大孔隙仅占大孔隙总数量的1.26%—8.55%,但决定了饱和导水率84.7%的变异。此外,森林土壤饱和导水率与各土壤层的有机质含量成显著正相关关系,有机质的增多有利于改善土壤的入渗性能。
[Abstract]:Macropore is the root hole, cave or fissure, which has larger pore diameter in soil, which can preferentially transmit water. The generation of preferential flow in macropore is the symbol of the study of soil moisture movement from equilibrium to disequilibrium. The macroporous structure of soil under different forest types in the three Gorges Reservoir area was studied by the water penetration test of undisturbed soil column. The yellow brown soil of temperate broad-leaved forest and mixed coniferous and broad-leaved forest was analyzed. Distribution characteristics of Macropores in Yellow soil and abandoned grassland profile of warm coniferous Forest and its effect on saturated Water conductivity of soil. The results showed that the equivalent pore size of the forest soil was between 0.3 and 3 mm, accounting for 0.15-4.72% of the total soil volume. In macropores, the pore density of 0.3-0.6 mm is the largest, accounting for 72.2% -90.4% of the total number of macropores, while the pore size of 1 mm is only 1.26-8.55% of the total number of macropores. The order of soil macropore density and macropore area ratio is: temperate broad-leaved forest brown soil mixed forest yellow brown soil coniferous forest yellow soil abandoned sloping land. The macropore density of each pore is decreasing gradually from layer A to layer B to layer C at different points, and there is a significant positive correlation between the macropore density and the content of organic matter. There was a significant positive correlation between saturated water conductivity and the density and area ratio of different pore size macropores. Macropores of pore size 1mm accounted for only 1.26-8.55% of the total number of macropores, but the variation of saturated water conductivity was 84.7%. In addition, there was a significant positive correlation between the saturated water conductivity of forest soil and the content of organic matter in each soil layer, and the increase of organic matter was beneficial to the improvement of soil infiltration performance.
【作者单位】：地理过程分析与模拟湖北省重点实验室;华中师范大学城市与环境科学学院;
【基金】：国家自然科学基金项目(41001125) 湖北省自然科学基金重点项目(2015CFA141)
【分类号】：S714.2

【参考文献】