When saline water is used to irrigate crops in arid environments, appropriate irrigation management should be applied to avoid negatively impacting soil characteristics. In this study, the effects of irrigating date palms with saline water (2,24 g l−1) on soil physicochemical characteristics such as the electrical conductivity (ECe), the pH of the saturated soil paste (pHe), the concentrations of soluble cations (Ca2+, Mg2+, Na+), the sodium adsorption ratio (SAR), the saturated soil hydraulic conductivity (Ks), and the volumetric water content of the soil (θv) were evaluated in a Tunisian Saharan cropland, the Dergine Oasis, during a 4-year period (2012–2015).
The effects of three different irrigation treatments of date palms on soil properties were investigated: low treatment (90% of the net irrigation requirement (NIR) of date palms was applied); medium treatment (100% of NIR was applied), and high treatment (110% of NIR was applied). The results showed that the application of saline water for irrigation inevitably has a negative impact on the physicochemical properties of the soil.
Irrigation with saline water was observed to have severe negative impacts on the soil characteristics, especially ECe, Na+, Ks, and θv. However, among the three irrigation treatments applied, statistical analysis (Duncan’s multiple range test) indicated that the high treatment significantly (p < 0.05) minimized the degradation of soil characteristics by the saline water; this treatment decreased ECe, Na+, and SAR and increased the water content, θv, of the studied soil.
Table of Contents
1. Introduction
2. Materials and methods
2.1 The Dergine Oasis
2.2 Experimental design and monitored plots
2.3 Soil sampling
2.4 Electrical conductivity of the saturated soil paste (ECe)
2.5 pH of the saturated soil paste (pHe)
2.6 Soluble cation concentrations (Ca2+, Mg2+, and Na+)
2.7 Sodium adsorption ratio (SAR)
2.8 Soil hydraulic conductivity (Ks)
2.9 Volumetric water content (θv)
2.10 Statistical analysis
3. Results and discussion
3.1 Effect of saline irrigation water on soil characteristics
3.2 Effects of the irrigation treatments on the soil characteristics
3.2.1 Effect on soil electrical conductivity (ECe)
3.2.2 Effect on soil water content (θv)
3.2.3 Effects on the Ca2+, Mg2+, and Na+ concentrations and the SAR
3.2.4 Effect on pHe
3.2.5 Effect on Ks
4. Conclusion
Research Objectives and Topics
This study aims to assess the long-term impact of irrigating date palms with saline water on soil physicochemical properties and to identify an irrigation treatment—specifically the volume of saline water—that minimizes soil degradation in arid environments.
- Effects of saline water on soil electrical conductivity and pH.
- Changes in soluble cation concentrations (Ca2+, Mg2+, Na+) and SAR.
- Impact of varying irrigation quantities on soil hydraulic conductivity and water content.
- Evaluation of optimal irrigation management to suppress soil salinization.
Excerpt from the Book
Effect of saline irrigation water on soil characteristics
We now present a comparison of the soil physicochemical characteristics before (January 2012) and after (December 2015) the application of saline water for irrigation to plot 2 (a medium irrigation treatment was applied in this plot). It is apparent from the results presented in Table 4 that the application of saline water for irrigation (2.24 g l−1 salinity) significantly (p < 0.05) changed the soil physicochemical characteristics in all three soil layers. As presented in Table 4, pHe decreased from neutral (7.2–6.9) in January 2012 to slightly acidic (6.5–6.1) by the end of the studied period. As reported by Roy et al. (2006), microbial activity and nutrient efficiency are maximized in neutral to slightly acidic soil, thus facilitating optimal crop growth. Also, the density of palm roots in the deep (60–90 cm) soil layer increases over time (Zaid and Jiménez 2002), which increases the amount of organic acid in this layer (i.e., the pH decreased with soil depth). This may be another reason for the increase in the observed soil acidity following three years of the saline water irrigation treatment.
Regarding the effects of the applied saline irrigation water on the soluble cation concentrations (Ca2+, Mg2+, and Na+) in plot 2, the following findings should be noted. First, the saline irrigation water decreased the calcium (Ca2+) concentration in the studied soil. The acidity level of the irrigated soil may be the main reason for this noticeable decrease (Fig. 3). Good irrigation management by the farmers during the studied period (i.e., a strategy to reduce the gypsum concentration) could be another reason for this decrease.
Summary of Chapters
Introduction: This chapter highlights the challenges of water scarcity in arid regions and the resulting necessity of using saline groundwater, which causes primary and secondary soil salinization.
Materials and methods: This section details the environmental conditions of the Dergine Oasis, the experimental design involving three irrigation treatments (low, medium, and high), and the standard analytical procedures used to measure soil properties.
Results and discussion: This core section analyzes the temporal changes in soil physicochemical properties and compares the efficacy of the three irrigation treatments in minimizing soil degradation.
Conclusion: This final chapter synthesizes the findings, concluding that higher irrigation volumes effectively suppress soil salinization through leaching, and recommends these strategies for sustainable agriculture in Saharan oases.
Keywords
Irrigation treatment, Soil characteristics, Saline water, Arid environments, Oasis, Soil salinization, Date palms, Electrical conductivity, Sodium adsorption ratio, Hydraulic conductivity, Sustainable agriculture, Tunisian Sahara, Leaching requirement
Frequently Asked Questions
What is the primary focus of this research?
The research focuses on evaluating the impacts of irrigating date palms with saline water on the physicochemical properties of soil in the Dergine Oasis over a four-year period.
What are the central themes of the work?
The central themes include soil salinity management, irrigation scheduling, the degradation of soil physical and chemical parameters, and strategies for sustainable agriculture in arid Saharan regions.
What is the primary objective of the study?
The primary objective is to identify an irrigation treatment—defined by the volume of water applied—that minimizes the negative impacts of saline irrigation on soil quality.
Which scientific methods were employed?
The study used a combination of field measurements, soil sampling at different depths, laboratory analyses (e.g., flame photometry, atomic absorption spectrophotometry), and statistical analysis (ANOVA and Duncan’s multiple range test) to evaluate results.
What topics are covered in the main section of the paper?
The main section covers the temporal changes in soil indicators like electrical conductivity (ECe), pH (pHe), soluble cation concentrations (Na+, Ca2+, Mg2+), SAR, hydraulic conductivity, and volumetric water content.
Which keywords best characterize this work?
Key terms include saline water irrigation, soil physicochemical characteristics, date palm cultivation, arid environments, and soil salinization mitigation.
How does the high irrigation treatment (110% of NIR) affect soil salinity?
The high irrigation treatment effectively reduces soil salinization by facilitating the leaching of salts from the soil profile, keeping electrical conductivity closer to the tolerance threshold of date palms.
Why did the study specifically focus on date palms?
Date palms are critical crops in Saharan croplands, and their high water requirements necessitate extensive use of saline groundwater, making the understanding of irrigation impacts vital for long-term productivity.
What role does the drainage system play in the Dergine Oasis?
The subsurface drainage system is essential for controlling the shallow groundwater table, preventing it from rising to critical levels and worsening soil salinization.
How did the soil acidity change over the four-year study period?
The study observed a shift in soil pH from neutral to slightly acidic, a process attributed to both the long-term saline water application and increased organic acid production from the dense palm root systems in deeper soil layers.
- Citation du texte
- Zied Haj-Amor (Auteur), Hossein Hashemi (Auteur), Salem Bouri (Auteur), 2018, The consequences of saline irrigation treatments on physicochemical soil characteristics, Munich, GRIN Verlag, https://www.grin.com/document/428105
