scholarly journals Using of pedotransfer functions for assessment of hydrolimits

2011 ◽  
Vol 48 (No. 9) ◽  
pp. 407-412 ◽  
Author(s):  
V. Štekauerová ◽  
J. Skalová ◽  
J. Šútor
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Region Of Interest ◽  
Calcium Content ◽  
Field Capacity ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Soil Water Retention ◽  
Laboratory Assessment ◽  
Retention Curve

Soil hydrologic coefficients, also called hydrolimits, are soil water contents defined for certain values of water potentials. Closer attention is paid to three hydrolimits: field capacity, point of decreased availability, and wilting point. The hydrolimits can be found by various ways. Their assessment under natural conditions should be seen as laboratory assessment of hydrolimit values or use of soil water retention curves for reading of hydrolimits. Therefore, some methods for indirect assessment of the water retention curve from actually mapped soil characteristics such as soil texture, bulk density and calcium content were devised. They are generally called pedotransfer functions (PTFs). Aim of the study is to calculate values of some important hydrolimits using PTFs. The hydrolimits calculated by this way are compared to hydrolimits determined from another measured water retention curves. The presented study documents an efficiency and promptness of PTFs use for a region of interest for dynamics evaluation of water storage in the soil aeration zone considering the water supply of plants.

Evaluation of soil texture data for estimating soil water retention curve

2009 ◽  
Vol 89 (4) ◽  
pp. 461-471 ◽  
Author(s):  
B Ghanbarian-Alavijeh ◽  
A M Liaghat
Keyword(s):  
Soil Water ◽  
Soil Texture ◽  
Water Retention ◽  
Geometric Mean ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Statistical Parameters ◽  
Retention Curve

The soil water retention curve (SWRC) is one of the basic characteristics used in determining soil hydraulic properties, including unsaturated hydraulic conductivity. As its measurement is time consuming and difficult, much effort has been expended to develop indirect methods, such as pedotransfer functions and empirical relationships, to estimate SWRC. In this study, three methods were evaluated based on estimation of retention models parameters and, consequently, the soil water retention curve. For this purpose, soil data collected from three data bases, totaling 72 soil samples with 11 different textures, were used in this study. The statistical parameters such as: MR (mean of residual), RE (relative error), RMSE (root mean square error), AIC (Akaike’s information criterion) and GMER (geometric mean error ratio) showed that the Saxton et al. (1986) method estimates the soil water retention curve better than the other methods.Key words: Pedotransfer function, soil texture, soil water retention curve

scholarly journals Developing Pseudo Continuous Pedotransfer Functions for International Soils Measured with the Evaporation Method and the HYPROP System: I. The Soil Water Retention Curve

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3425
Author(s):  
Amninder Singh ◽  
Amir Haghverdi ◽  
Hasan Sabri Öztürk ◽  
Wolfgang Durner
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Soil Samples ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Data Set ◽  
Retention Curve ◽  
Evaporation Method

Direct measurements of soil hydraulic properties are time-consuming, challenging, and often expensive. Therefore, their indirect estimation via pedotransfer functions (PTFs) based on easily collected properties like soil texture, bulk density, and organic matter content is desirable. This study was carried out to assess the accuracy of the pseudo continuous neural network PTF (PCNN-PTF) approach for estimating the soil water retention curve of 153 international soils (a total of 12,654 measured water retention pairs) measured via the evaporation method. In addition, an independent data set from Turkey (79 soil samples with 7729 measured data pairs) was used to evaluate the reliability of the PCNN-PTF. The best PCNN-PTF showed high accuracy (root mean square error (RMSE) = 0.043 cm3 cm−3) and reliability (RMSE = 0.061 cm3 cm−3). When Turkish soil samples were incorporated into the training data set, the performance of the PCNN-PTF was enhanced by 33%. Therefore, to further improve the performance of the PCNN-PTF for new regions, we recommend the incorporation of local soils, when available, into the international data sets and developing new sets of PCNN-PTFs.

scholarly journals Comparison Of Selected Pedotransfer Functions For The Determination Of Soil Water Retention Curves

2015 ◽  
Vol 23 (3) ◽  
pp. 33-36 ◽  
Author(s):  
Michal Kupec ◽  
Peter Stradiot ◽  
Štefan Rehák
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Undisturbed Soil ◽  
Retention Curve ◽  
Van Genuchten Model

Abstract Soil water retention curves were measured using a sandbox and the pressure plate extractor method on undisturbed soil samples from the Borská Lowland. The basic soil properties (e.g. soil texture, dry bulk density) of the samples were determined. The soil water retention curve was described using the van Genuchten model (Van Genuchten, 1980). The parameters of the model were obtained using the RETC program (Van Genuchten et al., 1991). For the determination of the soil water retention curve parameters, two pedotransfer functions (PTF) were also used that were derived for this area by Skalová (2003) and the Rosetta computer program (Schaap et al., 2001). The performance of the PTFs was characterized using the mean difference and root mean square error.

scholarly journals Estimation of the soil water retention curve (SWRC) using pedotransfer functions (PTFs)

2008 ◽  
Vol 2 (No. 4) ◽  
pp. 113-122 ◽  
Author(s):  
S. Matula ◽  
M. Mojrová ◽  
K. Špongrová
Keyword(s):  
Czech Republic ◽  
Soil Water ◽  
Water Retention ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
The Czech Republic ◽  
Retention Curve ◽  
Parameter Fitting

Soil hydraulic characteristics, especially the soil water retention curve and hydraulic conductivity, are essential for many agricultural, environmental, and engineering applications. Their measurement is time-consuming and thus costly. Hence, many researchers focused on methods enabling their indirect estimation. In this paper, W&ouml;sten&rsquo;s continuous pedotransfer functions were applied to the data from a selected locality in the Czech Republic, Ti&scaron;ice. The available data set related to this locality consists of 140 measured soil water retention curves, and the information about the soil texture, bulk density &rho;<sub>d</sub>, and organic matter content determined at the same time. Own continuous pedotransfer functions were derived, following the methodology used in continuous pedotransfer functions. Two types of fitting, 4-parameters and 3-parameters, were tested. In 4-parameter fitting, all parameters of the van Genuchten&rsquo;s equation, &theta;<sub>s</sub>, &theta;<sub>r</sub>, &alpha;, n, were optimized; in 3-parameter fitting, only three parameters, &theta;<sub>r</sub>, &alpha;, n, were optimised while the measured value of &theta;<sub>s</sub> was set as constant. Based on the results, it can be concluded that the general equations of W&ouml;sten&rsquo;s pedotransfer functions are not very suitable to estimate the soil water retention curves for the locality Ti&scaron;ice in the Czech Republic. However, the parameters of the same W&ouml;sten&rsquo;s equations, which were calculated only from the data for each particular locality, performed much better. The estimates can be improved if the value for the saturated soil water content &theta;<sub>s</sub> is known, applied and not optimised (the case of 3-parameter fitting). It can be advantageous to estimate SWRC for a locality with no data available, using PTFs and the available basic soil properties. In addition, to measure some retention curves and/or some their parameters, like &theta;<sub>s</sub>, can improve the accuracy of the SWRC estimation.

INFLUENCE OF SOIL MATRIX ON SOIL-WATER RETENTION CURVE AND HYDRAULIC CHARACTERISTICS

2017 ◽  
Vol 16 (4) ◽  
pp. 869-877
Author(s):  
Vasile Lucian Pavel ◽  
Florian Statescu ◽  
Dorin Cotiu.ca-Zauca ◽  
Gabriela Biali ◽  
Paula Cojocaru
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Hydraulic Characteristics ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Soil Matrix ◽  
Retention Curve
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