摘要
西藏地区丰富的水电资源可替代原有火电成为其清洁能源的主流,然而水电开发将改变河岸带土壤组成和结构,从而带来不可逆的生态环境影响。该文提出一套水电开发土壤肥力评价指数方法,分析拉萨河流域水电开发工程影响下,其河岸带土壤营养元素含量空间分布统计特征及趋势特征。结果表明：水电工程能够增加土壤中粗颗粒物含量的比重,使土壤抗侵蚀能力较差;河岸带土壤无机元素中钾元素含量较高,平均含量为2.4 mg/g,磷元素含量较低,平均含量为0.97 mg/g,拉萨河水电开发导致土壤中镁元素流失最为严重;根据水电开发土壤肥力评价指数得到拉萨河地区100 m范围内、100~200 m、200~300 m 3个不同空间尺度土壤肥力等级,结果显示拉萨河河岸带土壤肥力等级整体偏低,其中近岸100 m范围内水电开发所导致的土壤养分流失最为明显,建议适当控制流域放牧规模,通过水土保持工程恢复与植被恢复相结合的模式,减少水电工程开发引起的流域水土流失影响。
Tibet is rich in water resource and hydropower is a good alternative of the traditional thermal power plant. However, hydropower development will induce a significant effect on the hydrological regime of the river＇s upstream and downstream reaches, and induce irreversible ecological impacts. In this paper, a soil fertility evaluation indicator was proposed to identify the main influence of the riparian soil caused by hydropower development. Spatial pattern of four soil element concentrations, the determination of calcium （Ca）, magnesium （Mg）, potassium （K） and phosphorus （P） in Lhasa River from three different spatial scales were analyzed. Results showed that the soil particle size of downstream Lhasa River has a higher coarse sand fraction than that of upstream. The soil particle size of three spatial scales also showed that the soil texture within 100 meters has a higher coarse fraction than that of the distant shore, which is caused by hydropower development of the River. Average concentration of soil potassium is the highest as 2.4 mg/g, and average concentration of soil phosphorus is the lowest as 0.97 mg/g. Based on the overall element concentration rate of the River, the hydropower development has a severe negative effect on concentration of soil Mg. The assessment result of soil fertility evaluation indicator from three spatial scales showed that the River is suffering a relatively severe soil loss in the riparian region, especially in the off-shore area. Thus, considering the characteristics of the River, the combination of engineering restoration and vegetation recovery measures needed to be put forward to reduce the soil erosion rate and increase the soil formation rate in the River. What＇s more, moderate grazing should be carried out in the River watershed management to enhance the soil fertility at the same time.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2015年第5期148-156,194,共10页
Environmental Science & Technology
基金
国家环保公益项目(201209032)
国家基金委创新研究群体科学基金(5112100)
关键词
拉萨河
水电开发
土壤元素
土壤肥力评价指数
the River
hydropower
soil elements
soil fertility evaluation indicator
作者简介
李筱金（1988-），女，硕士研究生，主要研究方向为城市生态、环境经济、环境规划、评价与管理，（电子信箱）lixiaojingood@163．com；通讯作者。
