利用盘式负压仪测定土壤导水率的计算方法对比  

Comparison of methods for computing soil hydraulic conductivity measured by disc infiltrometer

作　　者：高雪梅[1,2] 佘冬立[1,2] 房凯 

机构地区：[1]河海大学南方地区高效灌排与农业水土环境教育部重点实验室,江苏南京210098 [2]河海大学水资源高效利用与工程安全国家工程研究中心,江苏南京210098 [3]江苏省宿迁市水务局,江苏宿迁223800

出　　处：《排灌机械工程学报》2015年第3期246-252,共7页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51109063;41471180);江苏省水利科技项目(2012079)

摘　　要：土壤导水率作为重要的水力特征参数之一,准确测量和计算不仅有助于促进土壤非饱和带的水分运动过程理论研究,同时可为合理确定农田灌排技术参数提供科学依据.为了比较分析在盘式入渗仪下不同导水率计算方法的适用性,针对2种土地类型(菜地、茶园)进行了4个负压水头(-9,-6,-3,0 cm)、2个盘径(10,20 cm)的入渗试验,并通过不同计算方法计算导水率.结果表明:盘径对导水率影响不具有统计学意义,且不同计算方法结果趋于一致,因此在野外缺水条件下,可考虑选用小圆盘进行试验;对于不同的土地类型,建议选择不同的方法测量,作为耕作地的菜地,计算导水率时建议使用稳态流方法,而茶园导水率的测定则推荐使用瞬态流方法;在相同负压下,不同土地利用方式对导水率的影响具有统计学意义,且对于不同的计算方法,2种土地类型在4个负压下表现的导水率变化规律一致.Soil hydraulic conductivity is one of the most important soil hydraulic parameters. Precisely measuring and computing the conductivity can not only promote the theoretical study on water flow process in an unsaturated soil but also can provide a scientific basis for reasonable determination of technical parameters in irrigation and drainage of farmland. To check the applicability of various methods for computing hydraulic conductivity, a series of infiltration experiments are conducted on the soils collected from vegetable and tea gardens by using a disc infiltrometer with 10 cm and 20 cm discs under four different negative pressure heads, namely - 9, - 6, - 3, and 0 cm. Then the conductivities are figured out by means of different computing methods. The results show that the hydraulic conductivity is less affected by the disc diameter, the conductivities given by various methods are nearly the same, and a smaller disc is therefore recommended for the field test. It is suggested that the choice of computing method for the conductivity depends on type of soil, for example, the conductivity of the soil from cultivated land such as a vegetable garden should be estimated by making use of a steady flow model, while for the soil in a tea garden, the transient flow model should be adopted. At the same pressure head, the hydraulic conductivity is obviously dependent on type of soil. The variations of hydraulic conductivity calculated by using different methods are almost the same under four pressure heads for two kinds of soil.

关 键 词：土壤入渗特性 圆盘入渗仪 土壤导水率 土地利用方式 计算方法 

分 类 号：S277.7[农业科学—农业水土工程]