The efficiency of various approaches to obtaining estimates of soil hydraulic properties

A formal analysis was carried out to evaluate the efficiency of the different methods in predicting water retention and hydraulic conductivity. Efficiency can be defined in terms of effort, cost or value of information. The analysis identified the contribution of individual sources of measurement errors to the overall uncertainty. The value of information summaries the quality of the prediction, the cost of information, the application of predicted hydraulic properties, and the effect of spatial variability. For single measurements, the inverse disc-permeameter analysis is economically more efficient than using pedotransfer functions or measuring hydraulic properties in the laboratory. However, given the large amount of spatial variation of soil hydraulic properties it is found that lots of cheap and imprecise measurements, e.g. by hand texturing, are more efficient than a few expensive precise ones. (C) 2002 Elsevier Science B.V. All rights reserved.