Isotopic Assessment of Groundwater Salinity: A Case Study of the Southwest (SW) Region of Punjab, India

In recent decades, due to rapid increases in water demand and greater usage of water for irrigation from surface canals, waterlogging problems have been created in the southwest zone of Punjab, coupled with a stagnation in saline zone formation due to salinity ingression. To understand these salinity issues, the present study has been conducted in three districts (Muktsar, Fazilka, and Faridkot) of Punjab to understand the root cause. To this end, groundwater samples were collected from 142 piezometers developed at 40 sites. Electrical conductivity (EC) observations were taken in the field, and collected samples were analyzed for isotopes in the laboratory. Results found that salinity in groundwater arises from the combination of evaporation enrichment and salt dissolution. The dissolved salts may be acquired due to salts from aquifer materials or salts from surface soils dissolving and leaching down with the recharging water. Besides, the zone of interaction is mapped using stable isotopic composition. The study suggests that zone of interaction between aquifers can be effectively used in groundwater augmentation, management, and contamination control at regional and/or global scales to curb water demand in the future.

The Influence of Groundwater Desalination by Modified Active Carbon/Bentonite on Its Application in Agriculture

It cannot be denied the importance of groundwater (Gw) as a source for irrigation. It is considered the only source of water in some locations such as newly reclaimed lands. However, the groundwater quality could be affected by salinity or heavy metals because of human activities or natural reasons. Thence, groundwater desalination comes to above as a part of the solution. In this study, the modified active carbon by inorganic iron polymer (Fex(OH)y) (Fe-AC) and bentonite (Ben) were used in groundwater desalination. The treatment process of 2 liters of groundwater was carried out by using a fixed-bed column where the flow rate was 120 mL/hour for each 20 grams sorbent. The results showed that the EC value of groundwater (2.54 dS/m) was reduced to 1.12 dS/m for treated groundwater (TGw) by Fe-AC/Ben mixture. Furthermore, the effect of irrigation by Gw and TGw was tested on the Faba bean and soil properties. The vegetative characters were significantly affected by irrigation by saline Gw while plant characters were much better after irrigation with TGw as well as soil chemical properties. Accordingly, the desalination of groundwater by Fe-AC/Ben mixture considers an effective and economic method that can be applied to reduce groundwater salinity and its impact on soil and crop.

Effects of Different Water Table Depth and Salinity Levels on Quality Traits of Bread Wheat

Abiotic stress factors encountered in production lands influence both the yield and the quality traits of bread wheat. This study investigated the effects of three different water table depths (30, 55, and 80 cm) and four different groundwater salinity levels (0.38, 2.0, 4.0, and 8.0 dSm−1) on some quality traits of bread wheat under irrigated and unirrigated conditions. The experiments were conducted in the 2018 and 2019 growing seasons in randomized blocks—factorial (three factors) experimental design with three replications under controlled conditions. The hectoliter weight, fat ratio, starch ratio, protein content, Zeleny sedimentation, wet gluten content, ash ratio, acid detergent fiber (ADF), and neutral detergent fiber (NDF) values were investigated. The hectoliter weights varied between 66.1% and 77.8 kg, fat ratios between 1.49% and 1.70%, starch ratios between 61.9% and 67.8%, protein contents between 11.9% and 13.8%, Zeleny sedimentation values between 23.5 and 28.0 mL, wet gluten contents between 25.0% and 28.8%, ash ratios between 1.43% and 1.75%, and ADF values between 2.85% and 4.12%. The quality traits were positively influenced by increasing the water table depths. With increasing the groundwater salinity levels, the hectoliter weight, fat ratio, starch ratio, and NDF values decreased, while the protein ratio, sedimentation value, wet gluten content, ash ratio, and ADF values increased.