不同土壤转换函数预测砂土非饱和导水率的对比分析
Estimating unsaturated hydraulic conductivity of sandy soils using different pedotransfer functions
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摘要: 以现有的4种土壤转换函数(Pedotransfer Functions, PTFs)(包括ROSETTA、RAWLS、CAMPBELL和VAUCLIN)为例,将其用于土壤水力性质数据库UNSODA中56个典型砂土样本的非饱和导水率预测,对4种PTFs的预测结果进行了误差分析,探讨了饱和导水率对非饱和导水率预测的影响。结果表明,当同种PTFs预测的饱和导水率作为输入时,在4种PTFs中VAUCLIN的预测精度最高,其次为ROSETTA和RAWLS,CAMPBELL的误差最大;当实测饱和导水率作为输入时,RAWLS、CAMPBELL和ROSETTA的预测精度有了不同程度提高,但VAUCLIN的预测误差反而有所增大;饱和导水率对非饱和导水率预测的影响较大,实测饱和导水率作为输入时CAMPBELL预测的非饱和导水率与实测值最为接近。Abstract: This study tested the ability of four published pedotransfer functions (PTFs) (including ROSETTA, RAWLS, CAMPBELL and VAUCLIN) to predict unsaturated hydraulic conductivity for 56 sandy soil samples from the UNSODA database. Different PTFs for the estimation of saturated hydraulic conductivity were also evaluated in this study. Results showed that among the four PTFs, VAUCLIN produced the best performance, followed by ROSETTA and RAWLS, and CAMPBELL gave the worst performance when saturated hydraulic conductivity predicted by the identical PTFs as input. The performance of RAWLS, CAMPBELL and ROSETTA has been improved to different extent when measured saturated hydraulic conductivity as input. However, VAUCLIN did not produce the best performance when measured saturated hydraulic conductivity as input. The influence of saturated hydraulic conductivity on the predictive accuracy of unsaturated hydraulic conductivity was significant. Overall, CAMPBELL gave the best performance when the measured saturated hydraulic conductivity was used in the functions for estimation of unsaturated hydraulic conductivity.
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