Sustainability of Groundwater for Irrigation Purposes in Semi-arid Parts of Namibia

The groundwater quality data from 1,137 boreholes in 10 regions of Namibia were assessed for sodium adsorption ratio (SAR), Kelly's ratio (KR), sodium percentage (Na%), magnesium adsorption ratio (MAR), total hardness (TH), soluble sodium percentage (SSP), potential salinity (PS), electrical conductivity (EC), and total dissolved solids (TDS) to determine the suitability for the irrigation. The groundwater was classified as follows: all the regions' groundwater shows the TH as very hard water of >4.6 meq/l, PS as not suitable for irrigation (>3 meq/l), and EC as very highly (0.75–2.25 dS/m). However, Na%: 10% of regions have doubtful water (>80%), MAR: 30% of regions are not recommended for irrigation (>50 meq/l), and TDS: 90% of the regions have slightly moderate (450–2,000 mg/l) and 10% have groundwater that is unsuitable for agricultural purposes (>2,000 mg/l). The unsuitability of groundwater for irrigation could be due to higher concentrations of K+, Mg2+, Ca2+, and Cl− that has exceeded the FAO guideline for irrigation. Some groundwater qualities had inverse classification such as SAR all regions have excellent groundwater (<10 meq/l), KR: 90% of regions have safe water (<1 meq/l), Na%: 50% of regions have good groundwater (20–40%), 40% of the regions have permissible water (40–80%), and MAR: +70% of region's water is recommended for irrigation (<50 meq/l).

Appraisal of Water Quality Measurements for Canal and Tube Well Water Systems for Agriculture Irrigation in Rechna Doab, Pakistan

The present study was an attempt to assess the surface and ground water quality for irrigation suitability in Rechna Doab. Irrigation water quality at canals and tube well water were analyzed by physicochemical parameters including pH, Electric Conductivity (EC), important cations such as Calcium (Ca2+) Magnesium (Mg2+), Potassium (K+), Sodium (Na+), important anions such as Chloride (Cl-), Bicarbonate (HCO3-), Sulphate (SO42-), three heavy metals including Zinc (Zn), Nickel (Ni) and Copper (Cu). Twelve water samples were collected from the main canals (Lower Gogera canal, Jhang branch canal and Rakh branch canal) while fifty water samples were collected from the tube wells. Statistically, data were analyzed by generating correlation coefficients. Canal water quality parameters i.e. Sodium Adsorption Ratio (SAR), Magnesium Adsorption Ratio (MAR), Sodium Percentage (Na %), Kelly Ratio (KR), Soluble Sodium Percentage (SSP), Residual Sodium Bicarbonate (RSBC), Permeability Index (PI) and Potential Salinity (PS) with their mean values 0.16,38.18, 8.03, 0.08, 10.17, 0.08, 28.34 and 0.024 respectively were calculated. Piper and Durov diagrammatic representations provided the suitability of the canal water regarding ionic composition. Results revealed that the status of the canal water was fit for agriculture. On the contrary, the data about Electric Conductivity (EC), Sodium Adsorption Ratio (SAR) and Residual Sodium Carbonate (RSC) of tube well water (with their maximum values 4.80, 29.65 and 13.60, respectively) was exceeding the FAO limits owing of sodium hazards. Thus, the scenario of groundwater is alarming due to unfit status of tube well water regarding irrigation purposes. Out of total 50 water samples of tube wells, 11 samples were found to be fit. While 39 samples were unfit for crop irrigation. Geo-statistical analysis was performed by using Inverse Distance Weighted (IDW) technique created in Arc map.

Characterization and evaluation of the effects of mine discharges on surface water resources for irrigation: a case study of the Enyigba Mining District, Southeast Nigeria

Mining activities generate much wastes which degenerate into various geochemical components and affect the natural composition of surface water resources. They cause Acid Mine Drainage (AMDs) and influence the hydrochemical evolution of the hydrogeological systems. This study employed hydrochemical parameters to characterize and evaluate the effects of mine discharges on irrigation surface water in the mining district of Enyigba, SE Nigeria. Twenty-four water samples were collected from surface water sources used for subsistence irrigation farming and analyzed for pH, total dissolved solids (TDS), electrical conductivity (EC), sodium (Na+), potassium (K), calcium (Ca2+), magnesium (Mg2+), bicarbonate (HCO3−), chloride (Cl−) and sulfate (SO42−), while various irrigation parameters including Soluble Sodium Percentage (SSP), Magnesium Adsorption Ratio (MAR), Sodium Percentage (Na %), Sodium Adsorption Ratio (SAR), Permeability Index (PI), Total Hardness (TH), Kelly Ratio (KR) and Electrical Conductivity (EC) were deduced. Result indicates hydrogeochemical trend of Cl− > Mg2+ > Ca2+ > SO42− > HCO3− + CO3 > Na+ + K+, while hydrogeochemical facies from Piper Trilinear plot, Durov and Schoeller plots shows that the dominant ionic species are the Mg2+, Cl−, and SO42−. Irrigation parameters such as SSP, MAR, Na %, SAR, PI, KR and EC indicate that majority of water sample are very good to moderately suitable for irrigation. Five samples around Amorie and Ameka are within the hard category for TH, which could be attributed to the high concentration of dissolved magnesium and calcium ion in the area. Apart from mine discharges, rock water interaction also affects the composition of surface water resources of the area.

Estimation of the Exchangeable Sodium Percentage from the Sodium Adsorption Ratio for salt-affected soils in Bolivia

<p>In order to obtain a more cost-time efficient way to determine the sodicity of salt-affected soils, this study aims to generate a regression model to predict the Exchangeable Sodium Percentage (ESP) from the Sodium Adsorption Ratio (SAR<sub>e</sub>). Based on a database with 84 soil samples from the High Valley of Cochabamba (Bolivia), two linear models were generated: <em>ESP= 0.9725 SAR + 1.5766 </em>(R<sup>2</sup>=0.85, RSE=4.47) and <em>ESP= 0.9197 SAR + 0.3813 </em>(R<sup>2</sup>=0.71, RSE=0.91)<em> </em>with square root transformation. Subsequently, through a set of 18 testing samples and a T-test of paired samples between the predicted ESP and measured ESP values, the efficiency of the generated models was verified with a value of p= 0.063 and 0.209, respectively, in contrast to p= 0.285 from the US Salinity Lab referential model. To improve the performance of the generated models, could be necessary a stratification according to soil sodicity levels and additional samples for the calibration dataset.</p>

HYDROCHEMICAL ASSESSMENT OF GROUNDWATER OF EUPHRATES AQUIFER IN ANAH, WESTERN IRAQ FOR IRRIGATION PURPOSES

Groundwater quality is of prime importance in determining its suitability for various human activity such as irrigation, therefore, groundwater samples are collected from selective wells in Anah city and subjected to hydrochemical analysis in order to measure the concentrations of the major ions, in addition to the Electrical Conductivity, pH, Total Dissolved Solids, Soluble Sodium Percentage (Na%), and Sodium Adsorption Ratio)SAR( to assess the suitability of groundwater for irrigation. Results showed that the groundwater in Anah city is characterized by excellent to good SAR with good Na% and accepted value of pH for irrigation, whereas, values of Electrical Conductivity and Total Dissolved Solids were not acceptable due to the rising of salinity (SO4 and Cl). According to Piper diagram, the type of water is Earth alkaline.

Assessment of Water Quality for Irrigation Purpose: A Case Study of Bassi and Chaksu Tehsils, Jaipur District, Rajasthan, India

Quality of Groundwater has assessed for irrigation purpose to get the suitability of water. Water samples has analysed by employing different parameters: Electrical Conductivity, Sodium Absorption Ratio (SAR), Soluble Sodium Percentage (SSP), Residual Sodium Carbonate (RSC), Kelly’s Ratio, Potential Salinity and Corrosive Ratio. Suitability of Water for irrigation has presented by the diagram based on the combination of Electrical Conductivity and Sodium Absorption Ratio suggested by United States Department of Agriculture (USDA). Livelihood of the study area depends on the Agriculture and allied activities so it becomes more important to analyse the quality of water for irrigation.Keywords: Irrigation, Electrical Conductivity, Sodium Absorption Ratio, Kelly’s Ratio, Soluble Sodium Percentage.