摘要
文章选择位于长江中游的洪湖流域作为研究对象，应用流域分布式水文模型SWAT，探讨传统农业条件下流域营养盐输移的规律。模拟时段选择为建国初期的1951～1960年，模拟的边界条件设置为自然地形、土壤、传统农业生产和土地利用方式，其中土壤资料包括营养盐（N和P）、有机质含量、粒径等理化参数等。根据流域汇水范围的变化，模拟分汛期与非汛期两个时间段进行。通过对模型参数率定和调试，水文模拟结果与实测值有较好的吻合程度，由此进行营养盐输出模拟。模拟结果显示，传统农业条件下流域营养盐输出，TN和TP浓度变化有明显的季节特征，体现了耕作制度对营养盐浓度的影响；同时，该时段营养盐浓度相比较自然条件下有了很大的改变，体现了人类活动对流域营养盐输移的影响，主要是土地利用类型变化和湖泊水域面积的缩小。
Excessive nutrient enrichment is one of the fundamental causes of eutrophication, which is greatly accelerated by human activities. To better understand the relationship between the natural environment-induced changes versus changes caused by human activities during the process of eutrophication, we tried to evaluate nutrient transportation over catchments and its contribution to lake eutrophication by working on the Honghu Lake Basin located at the middle reach of the Changjiang River, as an example. Numerical simulations with the SWAT model were used to rebuild nutrient deposition and transportation processes. SWAT （Soil and Water Assessment Tool） is a hydrological model developed by the Agriculture Research Service of US Department of Agriculture to analyze the principle of nutrient transportation which is the scientific basis for the mechanism research of eutrophication. Data sets for simulations were prescribed in the 1950s （ 1951 - 1960） in order to evaluate the traditional agricul- tural condition in the Honghu Lake Basin, including 1 ： 250000 digital elevation models, 1 ： 1000000 digital soil map with spatial and non-spatial information （soil bulk density, TN, TP concentration, et al. ） , 1 ： 100000 lake distribution map of 1950s, 1 ： 100000 landuse map of 1980, and 1951 - 1960 daily temperature/precipitation data. Total nitrogen （TN） and total phosphorus （TP） in the main channel transported into the lake were simulated during both the flood season （summer） and non-flood season （spring, fall and winter） respectively in each year. A stream network data set was created by digitizing 1 ： 100000 topography maps and using a ＂burn-in＂ method： A stream network theme would be superimposed onto the DEM to define the location of the stream network. The results show that the simulated model matches well the practically measured runoff values. The runoff of summer season occupies about 50% of the total year, with a quantity of about 51.9 × 10^8m^3 per year. The TN and TP concentrations simulated under traditional agriculture condition are 0.31mg/L and 0. 057mg/L respectively. The simulated TN and TP concentrations show significant seasonal changes, with the maximum and minimum values in spring and autumn respectively. Summer has relatively lower nutrient concentration due to the influence of the runoff. The nutrient loading has its peak value in summer, consistent with the peak of summer runoff. The total annual nitrogen and phosphorus loadings are 1823t and 303t respectively, much higher than those of our previous simulation for the beginning of the 20^th century in the same basin, suggesting a result of 36% decreas of water area and 80% increase of cultivated area such as the rice land and the wheat land from the beginning of the 20^th century to the 1950s of the Honghu Lake Basin. This simulation proves an effect of human activities on the catchment nutrient transportation.
出处
《第四纪研究》
CAS
CSCD
北大核心
2006年第5期849-856,共8页
Quaternary Sciences
基金
国家重点基础研究发展规划项目(批准号:2002CB412300-1)
中国科学院知识创新工程项目(批准号:KZCX1-SW-12-1)资助
关键词
营养盐输移
模拟
传统农业
洪湖流域
nutrient transportation, simulation, traditional agriculture, Honghu Lake Basin
