资源环境科技发展态势分析平台

Modeling soil hydraulic properties requires an effective representation of capillary and non‐capillary storage and conductivity. This is made possible by using physically comprehensive yet flexible soil hydraulic property models. Such a model (BW model) was introduced by Weber et al. (2019) and it overcomes some core deficiencies present in the widely used van Genuchten‐Mualem (VGM) model. We first compared the performance of the BW model to that of the VGM model in its ability to describe water retention and hydraulic conductivity data on a set of measurement of 402 soil samples with texture covering the entire range of classes. Secondly, we developed a simple transfer function to predict BW parameters based on VGM parameters. Combined with our new function, any existing pedotransfer function for the prediction of the VGM parameters can be extended to predict BW model parameters.

Based on information criteria, the smaller variance of the residuals, and a 40% reduction in mean absolute error in the hydraulic conductivity over all samples, the BW model clearly outperforms VGM. This is possible as the BW model explicitly accounts for hydraulic properties of dry soils. With the new pedotransfer function developed in this study, better descriptions of water retention and hydraulic conductivities is possible. We are convinced that this will strengthen the utility of the new model and enable improved field scale simulations, climate change impact assessments on water, energy and nutrient fluxes, as well as crop productivity in agroecosystems by soil‐crop and land‐surface modelling.