【摘要】 土壤含水量（θv）与电磁波在插入土壤的时域反射仪（TDR）探针中传播时间（T）的半理论、半经验标定曲线θv＝（T／Ta－Ts／Ta）／（Kw0.5－1）通常用于计算土壤含水量。本项试验应用TDR测定了不同质地及不同容重条件下烘干土壤的Ts／Ta值。结果表明，四种被测土壤的Ts／Ta值介于1．61～1．80，且土壤容重大，Ts／Ta值也大，三种农业土壤的Ts／Ta平均值可取1．68。用烘干至饱和含水量的砂质壤土和壤上的土柱试验结果表明，选用不同的Ts／Ta值，引起的含水量偏差分别为0．001～－0．005cm3／cm3和0．007～0．006cm3／cm3。对于砂质壤土，在实际合水量不变但改变土壤温度的情况下，TDR测定的含水量在实际含水量大于0．30cm3／cm3时有明显的偏差，且温度升高，TDR测定的含水量偏低，反之亦然。本文还给出了温度每增加（或减少）1℃引起的含水量测定值的偏差范围以及进行修正的方法。更多还原

【Abstract】 The semi-theoretical and -empirical calibration curve, θv = (T/ Ta--Ts/Ta) / (Kw0.5-1), soil water content (θv ) versus propagation time (T) of electromagnetic wave along TDR probe inserted in soil, is used to calculate soil water content. In this experiment TDR is used to measure Ts/ Ta value of oven-dried soils with different texture and bulk density. The result showed that Ts/Ta value from 1.61 to 1.80 for four soils, and the larger bulk density, the larger Ts/Ta value. For three agricultural soils the average Ts/Ta can be used as 1.68. The column experiments on sandy loamand loam showed (water content from oven-dry to saturation) that different Ts/Ta values lead to warer content deviation 0.001～-0.005 cm3/cm3 and 0.007～-0.006cm3/ cm3 respectively. For sandy loam with varied soil temperature, water content measured by TDR deviated from real values when it is higher than 0.30 cm3 /cm3. The higher temperature, the lower water content measured. This paper also indicates the deviation range of measured water content with temperature increasing (or decreasing) 1℃ and its modification method.更多还原