贵阳市花溪河岸喀斯特带地表径流中磷流失和土壤入渗分析

河岸带是流域生态系统水陆交错带,河岸带研究对重点流域环境保护和面源污染控制有着重要的意义。本研究选择贵州省贵阳市花溪河作为研究对象,通过野外实地调查对河岸带分类,利用河水模拟地表径流对不同类型河岸带的冲刷,并采用径流槽收集径流,测定径流中P含量,同时测定河岸带土壤磷相关化学性质、水分-物理性质,分析喀斯特河岸带P释放规律。结果表明:花溪河可划分为9种不同类型的河岸带;不同河岸带土壤水分累积入渗量差异显著,丘陵谷地+壤土+沟渠(护渠堤)+中重度干扰河岸带类型经五次加水后未产生径流,累积入渗量最高为4000±0 mL。河岸带土壤水分入渗量随着加水次数的增加而减小,最后达到稳渗。不同河岸带类型单位体积径流中总磷含量和磷酸盐含量差异均显著,丘陵谷地+渣土+风景名胜设施用地+中度干扰河岸带类型单位体积地表径流平均总磷含量和磷酸盐含量最高,分别为0.249±0.005 mg/L和0.242±0.003 mg/L,达到Ⅲ类地表水标准,且随着加水次数的增加,径流中的磷含量逐渐降低。试验所用的径流槽可用于收集地表径流,测定地表径流量,进而得到入渗量,认识土壤入渗和土壤P释放规律。

Simulation of the Phosphorus Loss in the Surface Runoff and Soil-water Infiltration in Karst Riparian Zones of Huaxi River in Guiyang City of China

A riparian zone is an ecotone between terrestrial ecosystem and water body in a watershed ecosystem.Understanding of the losses of phosphorous from the riparian zone plays an essential part in the environmental protection and the controls of non-point source pollution in major watersheds.This study took Huaxi River,which located in central Guizhou province,as an example to observe and analyze release of P from its karst riparian zones by simulating the surface runoff processes.Meanwhile,we classified the riparian zones by field survey and utilized river water to simulate surface runoff scouring on different riparian zones.We also adopted runoff trough to collect runoff,measure total P content in the runoff,as well as a relative property in the soils on the riparian zones,such as water contents,N,P,K contents,and pH.The results showed that:along the banks of Huaxi River,9 various kinds of riparian zones could be classified.Soil-water infiltration was significantly different among these types.After 5 times of water addition,the riparian zones "hill-valley + loam + ditch(dike dam canal) + moderately-severe-interference" did not yield runoff,which indicated the highest cumulative infiltration volume-4000 ± 0 occurred.The content of TP and phosphate in the surface runoff in different kinds of riparian zones was significantly different.The surface runoff from the riparian zones "hill-valley + waste-residue + scenic-spots-facilities + moderately-interference" contained the highest content of TP and phosphate,i.e.,0.249 ± 0.005mg/L and 0.242 ± 0.003 mg/L,respectively.The phosphorus content in the surface runoff declined gradually after the second addition of water to the runoff troughs.The runoff trough was a new tool that could be used to collect surface runoff and to calculate the volume of soil water infiltration,as well as to measure the P losses with the surface runoff.