滇池流域不同土壤类型和土地利用方式的土壤中溶解性有机碳的流失特性研究

摘要

采集滇池流域不同土壤类型、不同土地利用方式下的土壤样品,进行土壤中溶解性有机碳(DOC)的静态解吸实验,通过测定不同时间下溶入水相的COD量,探究不同土壤类型及土地利用方式下DOC的流失特性,从而揭示不同土地利用方式对滇池流域面源污染的影响.结果表明,同一土地利用方式的不同类型土壤中DOC的溶出平衡时间为壤土＞粘土＞粘壤土,其中退耕区(粘壤土＞粘土＞壤土)、大棚(粘土＞粘壤土=壤土)土壤不符合该规律,溶出平衡时间基本为1.5～2.5h；不同的土壤类型和土地利用方式下,DOC的溶出率为1.00％～2.75％,同一土地利用方式的不同类型土壤中DOC的溶出率存在一定差别,这是由于不同类型的土壤中砂粒、粉粒、粘粒的含量有所差异.%The soil samples of different types and in different land use pattern was collected from Dianchi Lake basin to carry out the static desorption experiment.By measuring the concentration of COD in aqueous phase,the author studied the releasing characteristic of dissolved organic carbon (DOC) from different soil samples,and further revealed the influence of land use pattern on non-point source pollution in Dianchi Lake basin.For most land use patterns,the DOC releasing balance time of different soil types followed the order of loam＞clay＞sticky loam,but the rule did not applied to soil in demolition area (sticky loam＞clay＞loam) and green house (clay＞sticky loam=loam).The DOC releasing time for different soil samples all ranged 1.5-2.5h.There was certain difference found in DOC dissolution rate among soils of different types and land use pattern (1.00％-2.75％),this is caused by the different contribution rate of sand,silt and clay to soil composition.