农田河道河岸土壤含水量变化特性分析研究

Study and Analysis of Soil Moisture Content Variation on Farmland Riverbank

河岸土壤含水量是选择农田河道护岸植物的一个重要影响因素。根据2008年10月-2009年9月对宁波农村地区3条典型农田河道河岸土壤含水量的周年监测结果,同时结合同期的降水量数据和河道水位数据,开展宁波农村地区农田河道河岸土壤含水量的变化特征研究。结果表明：（1）农田河道河岸不同位置的平均土壤含水量顺序为位置3（常水位至洪水位河岸区域）〉CK（岸边蔬菜地）〉位置2（洪水位至岸顶河岸区域）〉位置1（岸顶区域）,岸顶及洪水位以上河岸区域的土壤相对干燥,而常水位至洪水位之间河岸区域相对湿润,但此区域土壤含水量变化幅度大,长期处于旱湿交替状态;（2）河岸位置1和位置2的土壤含水量与采样当地3日内的降水量之和存在显著相关关系,河岸位置3的土壤含水量与降水量相关性不显著,而与河道水位高低存着极显著相关关系。（3）农田河道河岸不同位置的护岸植物选种需根据土壤含水量变化特征进行确定。

Soil moisture content of riverbank is an important factor in selecting plant species for riverbank protection of farmland rivers.The variations of characteristics of soil moisture content were investigated in detail for three typical farmland rivers in a rural area of Ningbo from September 2008 to October 2009 using monthly-monitored soil moisture contents on riverbank,in combination with precipitation data and river water levels.Results showed that the mean soil moisture on riverbank of farmland rivers decreased as follows： Location3（riparian zone between ordinary water level and flood water level） CK（vegetable field adjacent to the bank） Location 2（riparian zone between flood water level and riverbank top） Location 1（riverbank top）.The soils in the riparian zone above flood water level and top riverbank were relatively dry,while the soils in the riparian zone between ordinary water level and flood water level were relatively wet.However,soil moisture in the riparian zone between ordinary water level and flood water level fluctuated greatly,and that zone experienced a long period of alternating wetting and drying.The three days＇ cumulative precipitation was significantly correlated with the soil moisture contents in Location 1 and Location 2 but not with that of Location 3,which was highly correlated with river water levels.These results confirmed that selection of plant species for riverbank protection of farmland rivers should be based on characteristics of variation in soil moisture content that occur at different locations of the riverbank.