Extrapolative capability of two models that estimating soil water retention curve between saturation and oven dryness

PLoS One. 2014 Dec 2;9(12):e113518. doi: 10.1371/journal.pone.0113518. eCollection 2014.

Abstract

Accurate estimation of soil water retention curve (SWRC) at the dry region is required to describe the relation between soil water content and matric suction from saturation to oven dryness. In this study, the extrapolative capability of two models for predicting the complete SWRC from limited ranges of soil water retention data was evaluated. When the model parameters were obtained from SWRC data in the 0-1500 kPa range, the FX model (Fredlund and Xing, 1994) estimations agreed well with measurements from saturation to oven dryness with RMSEs less than 0.01. The GG model (Groenevelt and Grant, 2004) produced larger errors at the dry region, with significantly larger RMSEs and MEs than the FX model. Further evaluations indicated that when SWRC measurements in the 0-100 kPa suction range was applied for model establishment, the FX model was capable of producing acceptable SWRCs across the entire water content range. For a higher accuracy, the FX model requires soil water retention data at least in the 0- to 300-kPa range to extend the SWRC to oven dryness. Comparing with the Khlosi et al. (2006) model, which requires measurements in the 0-500 kPa range to reproduce the complete SWRCs, the FX model has the advantage of requiring less SWRC measurements. Thus the FX modeling approach has the potential to eliminate the processes for measuring soil water retention in the dry range.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Droughts
  • Models, Theoretical*
  • Soil / chemistry*
  • Water / chemistry*

Substances

  • Soil
  • Water

Grants and funding

This study was funded by the Natural Science Foundation of China (No. 41371240), the Beijing Natural Science Foundation (No. 6133035), the Basic Research Fund of RIF (No. RIF2014-09), and the CFERN & GENE Award Funds on Ecological Paper. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The funders are not linked in any way to a profit making organization.