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针对3种供试土壤,利用HYPROP系统与快速离心法分别测定了土壤在低吸力(800hPa以下)和高吸力(1×103～15×103 hPa)范围内土壤吸力和含水率的关系,并联合2种方法的测定结果,采用van Genuchten(1980)-Mualem拟合得到了土壤水分特征曲线的经验参数。其中快速离心法中用对数函数拟合了转速与压缩量间的关系,并利用压缩量对不同转速下的土壤吸力进行了修正。研究结果表明,利用HYPROP系统与快速离心法联合测定土水特征曲线,克服了HYPROP系统不能测定高吸力范围土壤水分特征曲线以及快速离心法对低吸力范围测定精度较差的缺点,在较短时间内可以准确测定低吸力和高吸力范围内的土壤水分特征曲线。土壤质地及孔隙分布是影响土壤水分特征曲线的主要因素。
The relationship between soil suction and soil water content under low suction (under 800 hPa) and high suction (1 × 103 ~ 15 × 103 hPa) was determined by HYPROP system and rapid centrifugation, According to the results of two methods, the empirical parameters of soil water characteristic curve were obtained by van Genuchten (1980) -Mualem fitting. In the rapid centrifugation method, the relationship between rotational speed and the amount of compression was fitted by a logarithmic function, and the soil suction at different rotational speeds was corrected by the amount of compression. The results show that the combination of HYPROP system and fast centrifugation can be used to determine the soil-water characteristic curve, which overcomes the shortcoming that the HYPROP system can not determine the soil moisture characteristic curve in the high suction range and the poor accuracy of the low-suction range in the rapid centrifugation method. Within the soil can accurately determine the low suction and high suction within the range of soil moisture characteristic curve. Soil texture and pore distribution are the main factors affecting the soil water characteristic curve.