Effect of free swelling index on improving estimation of the soil moisture retention curve by different methods

A - Papers appearing in refereed journals

Javanshira, S., Bayat, H. and Gregory, A. S. 2020. Effect of free swelling index on improving estimation of the soil moisture retention curve by different methods. Catena. 189, p. 104479. https://doi.org/10.1016/j.catena.2020.104479

AuthorsJavanshira, S., Bayat, H. and Gregory, A. S.

Several variables have been used to estimate the soil moisture retention curve (SMRC) so far, but one of the main points in using pedotransfer functions (PTFs) is the selection of readily available soil properties as inputs. In this study, 147 disturbed and undisturbed soil samples were taken from five provinces of Iran. Some soil properties such as particle size distribution (PSD), bulk density (BD), free swelling index (FSI) and SMRC were measured. A double exponential model was fitted to the SMRC data, and PTFs were developed to predict the model parameters,by multivariate linear regression and artificial neural network (ANN) methods. Using FSI with the soil basic properties (silt to sand ratio, clay and BD) as estimators improved the estimation of SMRC significantly for the full data set by ANN method (by 10.9 and 9.0% in the training and testing steps, respectively), and in the textural groups of “clay loam, silty clay loam”, “clay”, “loam”, “sandy loam” and “sand”, by the linear regression method in the range of 1.0 to 14.9%. Grouping the soil samples significantly improved the accuracy of the estimates, especially in the sandy soil textural group. In estimating SMRC using total data, ANN method had a greater accuracy compared with the linear regression method. In general, FSI significantly improved the accuracy of parametric estimation of the SMRC and grouping of data had a positive impact on improving estimates in some textural groups.

KeywordsArtificial neural network; Dexter model; Linear regression; Pedotransfer functions
Year of Publication2020
Journal citation189, p. 104479
Digital Object Identifier (DOI)https://doi.org/10.1016/j.catena.2020.104479
Web address (URL)https://doi.org/10.1016/j.catena.2020.104479
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeS2N - Soil to Nutrition - Work package 1 (WP1) - Optimising nutrient flows and pools in the soil-plant-biota system
Output statusPublished
Publication dates
Online14 Feb 2020
Publication process dates
Accepted15 Jan 2020
PublisherElsevier Science Bv

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