Predicting the Campbell-Shiozawa soil-water retention function for the dry region: comparing visible – near infrared spectroscopy with a classical pedotransfer function

Research output: Contribution to conferencePosterResearch

The soil-water retention curve (SWRC) at the dry end, also known as soil water vapor sorption isotherms, is essential for the modelling of water vapor transport, microbial activity and biological processes such as plant water uptake in the vadose zone. Measurement of detailed soil water vapor sorption isotherms (WSIs) can be time-consuming. Therefore, we propose rapid, inexpensive methodologies (vis−NIRS and a pedotransfer function) to predict the Campbell-Shiozawa (CS) model parameters to obtain the WSIs. Water vapor sorption isotherms were measured on 144 soil samples (clay: 0.04–0.46 kg kg-1, organic carbon: 0.009–0.084 kg kg-1) from Denmark, Germany and the USA with a Vapor Sorption Analyzer. The CS semi-logarithmic-linear function anchored at a soil-water matric potential of -106 cm H2O (log|-106|=pF 6) was fitted to the measured data, since it accurately characterizes the WSIs. Thereafter, a vis−NIRS calibration model and a pedotransfer function (PTF), based on clay and organic carbon contents, were developed and used to predict the two CS model parameters (α, and W6). Both parameters were predicted with a reasonable degree of accuracy using vis−NIRS and the PTF (for α, RMSE values of 0.0041 and 0.0025, and for W6, RMSE values of 0.0042 and 0.0034, respectively, for vis−NIRS and the PTF). Based on the predicted α and W6 values, the predicted WSIs compared closely to the measured isotherms for individual soil samples from each field. At the field scale, the vis−NIRS model performed marginally better than the PTF. Thus, it is evident that the use of vis−NIRS and PTFs provides a relatively inexpensive approach to predicting soil water sorption isotherms.
Original languageEnglish
Publication year2019
Publication statusPublished - 2019
Event2018 - 2019 SSSA International Soils Meeting : SOILS ACROSS LATITUDES - Sheraton San Diego Hotel & Marina, San Diego, United States
Duration: 6 Jan 20199 Jan 2019
https://www.sacmeetings.org/

Conference

Conference2018 - 2019 SSSA International Soils Meeting
Location Sheraton San Diego Hotel & Marina
CountryUnited States
CitySan Diego
Period06/01/201909/01/2019
Internet address

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