【摘要】 以均质沙壤土和由沙壤土与沙土组成的层状土为材料,在室内对中子水分探测仪进行了土壤水分标定试验。供试土壤装填在直径57 cm、高90 cm的塑料桶内,其中层状土的分层次序为沙壤土、沙土、沙壤土,每层厚度30 cm。试验中同时观测中子计数和土壤质量含水率;利用统计学方法分析中子计数与土壤含水率之间的相关关系。试验结果表明:中子计数与土壤含水率之间的标定关系存在有效适用范围,即当土壤含水率低于某一个值时,中子仪的标定关系与大于该值时的标定关系完全不同;中子仪在均质土壤中的标定关系可用线性关系表示,而且用整体标定的线性关系代替分层标定的线性关系仍然可以得到满意的精度;但是,中子仪在层状土壤中的标定关系表现出明显的非线性特点,如果用线性关系来标定,则只有用分层标定才能得到满意的精度。该研究结果对改进中子仪标定方法有帮助。更多还原

【Abstract】 Homogeneous sandloamandlayered soil consisting of sandloamand sandy soil are usedinthe experi ments to calibrate neutron probe in soil moisture measurement.The soil is filled in the plastic barrels with 57 cmdiameter and 90cmheight,and the layered soil is filledin the order of sandloam,sandy soil,and sandloam,withlayer thickness of 30cm.In the experi ment,the neutron counting and the soil weight moisture content are observed si multaneously,and their calibrated relations are analyzed withthe statistical methods.The experi mental results indicate that the calibrated function between the neutron counting and the soil weight moisture content which belowa certain value is different fromthat of the soil moisture content whichis greater than the value.The calibrated function for the homogeneous soil is linearity,and the calibrated accuracy of the neutron probe for entire homogeneous soil is si milar to that for stratified homogeneous soil.But the calibrated function of the neutron probe in the layered soils is obviously nonlinearity,and linear functions are only available for the neutron probe in stratified calibrationinlayered soil for a satisfactory accuracy.The results of these experi ments are helpful to i mprove the methods to calibrate the neutron probe in soil.更多还原