Effect of Irrigation Water pH on Saturated Hydraulic Conductivity and Electrokinetic Properties of Acidic, Neutral, and Alkaline Soils

Ali, Aram; Biggs, A. J. W.; Marchuk, Alla; Bennett, John McLean

doi:10.2136/sssaj2019.04.0123

Cited by 33 publications

(13 citation statements)

References 57 publications

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“…Most existing models for the dynamics of salinity and sodicity, by contrast, are not capable of considering the effect of soil type on changes to hydraulic conductivity. While the advantages of a soil‐specific approach have been demonstrated, the incorporation of soil‐specific considerations into existing models for the dynamics of salinity and sodicity has been hampered, possibly due to difficulties in modifying the code of these existing models (Ali et al, 2019; van de Craats et al, 2020). As an open‐source program coded in Python, SOTE is easily amenable to user modifications.…”

Section: Discussionmentioning

confidence: 99%

Soil Degradation Risks Assessed by the SOTE Model for Salinity and Sodicity

Kramer

Mau

2020

Water Resources Research

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Soil salinity and sodicity are serious environmental hazards, with the potential to limit agricultural production and cause destructive soil degradation. These concerns are especially high in dry areas, which often rely on saline and sodic irrigation water to support agriculture. To assess long-term soil degradation risk, we introduce the Salt of the Earth (SOTE) model, which describes the dynamics of soil water content, salinity, and sodicity, as driven by irrigation and rainfall. The SOTE model incorporates how changes in salinity and sodicity affect saturated soil hydraulic conductivity, K s , on a soil-specific basis. The model was successfully validated against results from a multiyear lysimeter experiment involving different irrigation water qualities and precipitation. We evaluated the impact of shorter rainy seasons on the dynamics of soil degradation in a Mediterranean climate. Critical degradation risk, indicated by reductions in K s greater than 20%, increased from 0% to 3% when the rainy season was shortened from 130 to 80 days. Alarmingly, when irreversible degradation is allowed for, overall risk increases to 68%. Assessing the effect of irrigation water on different soils textures, we found that while greater clay fractions are usually more susceptible to dispersion, accurate risk assessment hinges on soil water dynamics. SOTE is amenable to large-ensemble simulations of stochastic climatic conditions, for which trends in the statistics of salinization and soil degradation can be identified. As such, SOTE can be a useful land management tool, allowing planners to understand the risk of long-term soil degradation given irrigation practices, soil qualities, and climate conditions.

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Section: Discussionmentioning

confidence: 99%

Soil Degradation Risks Assessed by the SOTE Model for Salinity and Sodicity

Kramer

Mau

2020

Water Resources Research

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“…This may suggest that the initial soil pH is not important in predicting the hydraulic conductivity decline. However, we caution that this assumption is on the basis of the study of Ali et al (2019), who demonstrated that the initial soil pH and the clay content were both important in controlling the extent of the hydraulic conductivity reduction. The same nine soils were used in this work.…”

Section: Soil Initial Ph and Hydraulic Conductivity Reductionmentioning

confidence: 96%

“…3). From these data, a generalized r 2 function was also formed using the same approach as Šimůnek and Suarez (1997), based on the results of r K s for the soils used in the study of Ali et al (2019) and presented in (Fig. 1 and 2).…”

Section: Modification Of the Hydraulic Reduction Scaling Factor For Phmentioning

confidence: 99%

A pH‐Based Pedotransfer Function for Scaling Saturated Hydraulic Conductivity Reduction: Improved Estimation of Hydraulic Dynamics in HYDRUS

Ali

Biggs

Šimůnek

et al. 2019

Vadose Zone Journal

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Soil‐specific pedotransfer functions can be incorporated into the HYDRUS model. Electrolyte concentration reduces the adverse effect of pH and Na on soil structural stability. Clay content is important in governing soil hydraulic reduction dynamics due to pH. Hydraulic conductivity is a key soil property governing agricultural production and is thus an important parameter in hydrologic modeling. The pH scaling factor for saturated hydraulic conductivity (Ks) reduction in the HYDRUS model was reviewed and evaluated for its ability to simulate Ks reduction. A limitation of the model is the generalization of Ks reduction at various levels of electrolyte concentration for different soil types, i.e., it is not soil specific. In this study, a new generalized linear regression model was developed to estimate Ks reduction for a larger set of Australian soils compared with three American soils. A nonlinear pedotransfer function was also produced, using the Levenberg–Marquardt optimization algorithm, by considering the pH and electrolyte concentration of the applied solution as well as the soil clay content. This approach improved the estimation of the pH scaling factor relating to Ks reduction for individual soils. The functions were based on Ks reduction in nine contrasting Australian soils using two sets of treatment solutions with Na adsorption ratios of 20 and 40; total electrolyte concentrations of 8, 15, 25, 50, 100, 250, and 500 mmolc L−1; and pH values of 6, 7, 8, and 9. A comparison of the experimental data and model outputs indicates that the models performed objectively well and successfully described the Ks reduction due to the pH. Further, a nonlinear function provided greater accuracy than the generalized function for the individual soils of Australia and California. This indicates that the nonlinear model provides an improved estimation of the pH scaling factor for Ks reduction in specific soils in the HYDRUS model and should therefore be considered in future HYDRUS developments and applications.

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“…This might take place because both the clay and organic matter contents in soils probably formed layers of low filtration rates (Patle et al, 2019). Moreover, clay particles reserve Na ions in soil; which consequently increased clay dispersion (Ali et al, 2019), while decreased soil hydraulic conductivity (Arienzo et al, 2012).This is an important aspect for water and salts transportation (Klopp and Daigh, 2019). Thus, there is no wonder to find out that the total concentrations of trace elements significantly and negatively correlated with soil ESP (Table 2).…”

Section: Ab-dtpa Extractable (Available) Contents Of Trace Elements Imentioning

confidence: 99%

Monitoring Environmental Pathways of Trace Elements in the Northern East Area of Egypt

Bassouny

Abbas

2020

EBSS

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N ILE Delta aquifer is one of the largest aquifers worldwide that receives the agrochemical leachates from the surrounding environments. To assess the status of some trace-elements (As, Co, Cd, Pb, Cu and Ni) in the NorthEast area of Egypt, well-water samples beside of surface, subsurface and deep-soil-samples were collected from 17 different locations to represent three environmental-pathways: the first one signifies areas relatively nearby Damiettabranch, while the third pathway stands for the arable lands nearby Ismaellia-canal. The second pathway is in-between these two pathways. Furthermore,a reference soil (irrigated with fresh-Nile-water) was sampled for data comparison.These samples were estimated for their total and AB-DTPA-extractable contents of the aforementioned trace elements (TEs). Results revealed that AB-DTPA-extractable-TEs were in dynamic equilibrium with the corresponding soluble contents in irrigation water. Likewise, AB-DTPA-extractable-TEs significantly correlated with their corresponding total contents in soil. Concentrations of TEs in surface-soil-layer were higher than the corresponding ones in the subsurface and deep-soil-layers. The calculated values of contamination factor indicated moderate to very high levels of soil contamination with TEs. According to the principal component analysis, total and AB-DTPA-extractable-TEs in soil were affected by only one-principal-component, recording 86.13 % of the data variance. This indicates that these contaminants originated probably from the same source. Moreover, multivariate-analyses revealed that total TEs significantly and positively correlated with soil hydraulic conductivity and bulk density, while negatively correlated with exchangeable sodium percentage, clay and organic matter contents. These results indicate that the groundwater flow is the potential source that enriched soils with TEs. Accordingly, any reductions in effluents of fresh Nile water, which is in hydraulic continuity with the groundwater in the studied area, can increase the severity of soil pollution with TEs in the studied area.

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Effect of Irrigation Water pH on Saturated Hydraulic Conductivity and Electrokinetic Properties of Acidic, Neutral, and Alkaline Soils

Cited by 33 publications

References 57 publications

Soil Degradation Risks Assessed by the SOTE Model for Salinity and Sodicity

Soil Degradation Risks Assessed by the SOTE Model for Salinity and Sodicity

A pH‐Based Pedotransfer Function for Scaling Saturated Hydraulic Conductivity Reduction: Improved Estimation of Hydraulic Dynamics in HYDRUS

Monitoring Environmental Pathways of Trace Elements in the Northern East Area of Egypt

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