Soil water flux (/. ) is an important hydrological parameter which determines soil infiltration, runoff and solute transport, yet no corresponding practical techniques are available for its real-time measurement in situ. In this study, heat-pulse measurements were performed of deferent water fluxes in packed soil columns different in texture. Based on temperature changes between upstream and downstream locations from the heat-pulse probe, water flux was then calculated with the MDTD method (maximum dimensionless temperature increase difference) , and the Td/Ta method (ratio of temperature changes between downstream and upstream positions) , and a modified Td/Ta method along other known parameters. Results indicated that strong linear relationships (R2 >0. 99) existed between the estimated and the measured water fluxes ( up to 6 x 10" m s" ) . Though, the three methods all down-estimated, however, the Td/Tu method was highest precise and simplest in calculation, and needed the least number of additional parameters. In coarse sand, the Tt/Ta method was relatively more accurate in estimation of Jw, yet in fine sandy clay loam, especially when Jw was greater, obvious discrepancies were observed between the estimated and the measured, reaching 20% . Besides, the reason of underestimation of Jw with the heat-pulse technique is explored and presented as a basis for further development of the heat-pulse technique.%土壤水流通量(Jw)是一个重要的水力学参数,决定着土壤渗漏、径流和化学物质的迁移过程,但缺少相应的实际技术来进行实时定位测定.本研究通过设置室内一维饱和土壤不同水流速率下的热脉冲试验,根据热脉冲技术测定的热源上下游温度变化,利用上下游最大无量纲温差法(MDTD)、上下游温度升高比率法(Td/Tu)及改进的比率法估算Jw,并检验其可靠性.结果表明,三种方法估算的Jw与通过收集出流液测定的Jw存在很好的线性关系(R2＞0.99)(Jw＜6×10-5 ms-1).三种方法估算的.Jw均低于出流液测定值,其中Td/Tu估算的Jw精度最高,而且计算简单,需要的参数相对较少.对于质地较粗的砂土,Td/Tu法估算的Jw较为准确,但是对于质地较细的砂质黏壤土,尤其是Jw较大时,实测值和估算值差异很大,估算误差达到20％.此外,本文也分析了热脉冲技术低估Jw的原因,为进一步发展热脉冲技术提供依据.
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