喀斯特洼地退耕和耕作土壤优先流特征  

Characteristics of Preferential Flow in Soil of Abandoned Farmland and Cultivated Land of Karst Depression

作　　者：王发[1,2,3] 付智勇[1,2] 陈洪松[1,2] 王克林[1,2] 

机构地区：[1]中国科学院亚热带农业生态研究所/中国科学院亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院环江喀斯特生态系统观测研究站,广西环江547100 [3]中国科学院大学,北京100049

出　　处：《水土保持学报》2016年第1期111-116,共6页Journal of Soil and Water Conservation

基　　金：中国科学院西部行动计划项目(KZCX2-XB3-10);国家自然科学基金项目(41171187;31100294);湖南省自然科学基金项目(14JJ3144)

摘　　要：应用亮蓝染色示踪技术,研究了喀斯特洼地退耕封育区土壤和耕作土壤的优先流类型及其特征,分析2种土地利用方式下的土壤优先流路径分布特征以及影响因素,并结合去除耕作层的对比试验,阐述了耕作层对优先流发生及其优先流路径发育的重要影响。结果表明,喀斯特洼地优先流类型为大孔隙流、裂隙流;耕地与自然封育区的优先流程度差异显著(P<0.01),虽然其剖面染色总面积并无明显差异,但耕地染色区域主要集中在表层土壤,0—20cm范围内染色面积占染色总面积的91%,而自然封育区染色面积比仅为60%;耕地的水分入渗深度小于自然封育区,耕作层阻碍了水分入渗及优先流的产生并加强了孔隙中水分与基质的交换;耕作层以下土壤优先流程度与自然封育区差异不明显,但其优先流路径分布特征具有明显差异,自然封育区的孔隙、裂隙发育程度高于耕地,但是最大入渗深度大于退耕封育区,表明封育区更能有效的蓄持水分;植被覆盖及其根系生长通过影响土壤理化性质及其优先流路径分布导致优先流特征差异,而同时耕作层的存在对于耕作层以下部分优先流路径的发育起到关键作用。In this study,the dye tracing method was used to investigate the characteristics and types of preferential flow in soil of abandoned cropland in enclosed zone and cultivated land,and to analyze the difference in the distribution characteristics of preferential flow paths and their influencing factors based on contrast experiment excluding plough layer of soil,exploring the effects of plough layer on the development and paths of preferential flow.The results showed that the preferential flow in the soil profile of Karst depressions belonged to macropore flow and fractured flow.There were significant differences in preferential flow patterns between cropland and enclosed abandoned cropland（p〈0.01）.Although the soil profiles of the 2types of experimental lands had the same total dyeing area,the dyeing area was mainly distributed in the topsoil of cropland,with91% of dyeing area in 0—20cm soil layer,while only 60% of dyeing area was distributed in 0—20cm soil layer of the enclosed land.The infiltration depth in soil of cropland was smaller than that of the enclosed land,because the plough layer blocked the infiltration of water,prevented the production of preferential flow and enhanced the exchange between water and substrate.Below the plough layer,the difference of preferential flow between enclosed land and cropland was not significant,but the distribution of preferential flow paths was different.In the enclosed land,the development of marcopores and cracks was better than that in cropland,while the maximum infiltration depth showed an opposite tendency,which suggested that the enclosed land showed better water conservation capacity.The different characteristics of preferential flow were influenced by vegetation coverage and the growth of roots,which could influence soil physical andchemical characteristics and the distribution of preferential flow.Meanwhile,the plough layer plays an important role in impacting the formation of preferential flow paths in farmland below the plough layer.

关 键 词：喀斯特 优先流 退耕还林 染色示踪 

分 类 号：S152[农业科学—土壤学] S157[农业科学—农业基础科学]