Abstract
The saturated hydraulic conductivity (Ks) and water retention curve (SWRC) parameters are important properties for simulating soil hydrological processes and characterizing soil conservation around the world. Therefore, Ks and SWRC are related with the soil physical quality (SPQ) and several SPQ indices can be derived from SWRC, such as the pore size distribution, relative field capacity, plant available water, drainable porosity, and soil hydraulic-energy indices (SHEI). It is well known that the soil structure can be assessed by using SHEI, but a possible physical relationship between Ks and SHEI was not examined yet. Therefore, the objective of this study was to investigate the behavior of Ks as function of SHEI for several soil textural classes. If this relationship be proved, then SHEI might be applied to improve the Ks prediction by PTF models. In this work, a data set of 395 measured SWRC's were fitted to the vG equation to obtain the SHEI to verify whether they are statistically correlated and physically dependent on Ks. The resulting parametric and non-parametric correlation results were split up according to six textural classes. The significant influence of Ks on at least one of the absolute SHEI (Aa or WRa) was verified on the numerical scale when all textures were grouped and on numerical and pF scales for clayey and silty textures. Ks showed significant impact on Aa and WRa indices in four textural classes. Furthermore, Ks had influence on the sum Aa + WRa denoted in pF scale for five of the six textural classes, with a significant linear correlation in the clayey texture when log (Aa + WRa) was applied. The significant and high correlation of Ks on the ratios WRa/AWC and Aa/φD was also observed in four of the six classes, and therefore the use of these indices is recommended for the development of PTFs for Ks prediction.
| Original language | English |
|---|---|
| Pages (from-to) | 798-807 |
| Number of pages | 10 |
| Journal | International Soil and Water Conservation Research |
| Volume | 12 |
| Issue number | 4 |
| DOIs | |
| State | Published - Dec 2024 |
Bibliographical note
Publisher Copyright:© 2024 International Research and Training Center on Erosion and Sedimentation, China Water and Power Press, and China Institute of Water Resources and Hydropower Research
Funding
The soil hydraulic-energy-indices (SHEI), extracted from the integral of the soil water retention curve (SWRC) and equated from SWRC's parameters (Rastgou et al., 2020; Peters et al., 2021), are examples of SPQ indicators. Although Armindo & Wendroth (2016) and Dos Reis et al. (2019) theoretically defined and applied Ks as a soil property associated with the absolute aeration index (Aa), the physical relationship between Ks and SHEI was not examined and identified yet. If the link between Ks and SHEI were proven, these indices might also be used as input parameters for pedotransfer functions (PTFs) to predict Ks (Pachepsky et al., 2014; Koureh et al., 2019). PTFs are important tools to help scientists and consultants to predict, for example, the available water content (AWC) and drainable porosity (∅D) that are applied to support the management of the soil, crops, and irrigation systems. Pachepsky & Rawls (2003) reported that the accuracy of PTFs for predicting water retention and soil hydraulic conductivity typically increases when they are developed based on both soil textural and structural attributes. In an attempt to simplify the PTF input, Lin et al. (1999) used only textural information, i.e., percentages of clay and sand to develop a PTF for Ks. Besides that, there are computational models built under PTFs to estimate Ks, such as Splintex 2.0 that require as input parameters the frequency distribution of the granulometric particles and bulk density (Da Silva et al., 2020a). The prediction performance of Splintex 2.0 was evaluated for different soil textural classes estimating log10(Ks) with precision (r = 0.48) and accuracy (RMSE = 1.17) (Da Silva et al., 2020b) in comparison with Ks measured in situ by the instantaneous profile method. Before that, Wösten et al. (1999) have already developed PTFs to predict Ks based on the parameters of the SWRC equation of Van Genuchten (1980) (vG) using the European database HYPRES. The authors emphasized that calibrated PTFs should not be used to predict soil hydraulic properties from outside Europe due to different specific soil local conditions.The funding brazilian agencies CNPq, CAPES, and FAPEMIG are acknowledged by the first, second, and fourth authors to support their scholarships. The fifth author [ow] acknowledges support through the Multistate Project KY006120 “Soil, Water, and Environmental Physics to Sustain Agriculture and Natural Resources” and from the University of Kentucky Agricultural Experiment Station. The fifth author [ow] acknowledges support through the Multistate Project KY006120 “Soil, Water, and Environmental Physics to Sustain Agriculture and Natural Resources” and from the University of Kentucky Agricultural Experiment Station.
| Funders | Funder number |
|---|---|
| Environmental Physics to Sustain Agriculture and Natural Resources” | |
| Conselho Nacional de Desenvolvimento Científico e Tecnológico | |
| Coordenação de Aperfeiçoamento de Pessoal de Nível Superior | |
| PTFs | |
| Stroud Water Research Center | |
| University of Kentucky Agricultural Experiment Station | |
| Fundação de Amparo à Pesquisa do Estado de Minas Gerais | KY006120 |
| Fundação de Amparo à Pesquisa do Estado de Minas Gerais |
Keywords
- Soil permeability
- Soil physical quality
- Soil structure
- Soil water retention curve
ASJC Scopus subject areas
- Agronomy and Crop Science
- Water Science and Technology
- Soil Science
- Nature and Landscape Conservation