Potential Soil Salinity Research Articles

Hydrogeochemical features, genesis, and quality appraisal of confined groundwater in a typical large sedimentary plain.

The confined groundwater of arid sedimentary plains has been disturbed by long-term anthropogenic extraction, and its hydrochemical quality is required for sustainable development. The present research investigates the hydrochemical characteristics, formation, potential health threats, and quality suitability of the confined groundwater in the central North China Plain. Results show that the confined groundwater has a slightly alkaline nature in the study area, predominantly dominated by fresh-soft Cl-Na and HCO3-Na types. Water chemistry is governed by water-rock interactions, including dissolution of evaporites and cation exchange. Approximately 97% of the sampled confined groundwaters exceed the prescribed standard for F-. It is mainly due to geological factors such as mineral dissolution, cation exchange, and competitive adsorption of HCO3 - and may also be released from compacted soils because of groundwater extraction. Enriched F- in the confined groundwater can pose an intermediate and higher non-carcinogenic risk to more than 90% of the population. It poses the greatest health threat to the population in the north-eastern part of the study area, especially to infants and children. For sustainable development, the long-term use of confined groundwater for irrigation in the area should be avoided, and attention should also be paid to the potential soil salinization and infiltration risks. In the study area, 97% of the confined groundwaters are found to be excellent or good quality for domestic purposes based on Entropy-weighted Water Quality Index. However, the non-carcinogenic health risk caused by high contents of F- cannot be ignored. Therefore, it is recommended that differential water supplies should be implemented according to the spatial heterogeneity of confined groundwater quality to ensure the scientific and rational use of groundwater resources. PRACTITIONER POINTS: The hydrochemistry quality of confined groundwater in an arid sedimentary plain disturbed by long-term anthropogenic extraction was investigated. The suitability of confined groundwater for multiple purposes such as irrigation and drinking were evaluated. The hydrochemical characteristics and formation mechanism of confined groundwater under the influence of multiple factors were revealed.

Quantitative Inversion of Soil Salinity in Different Seasons in Huinong District, Ningxia based on Sentinel-2 satellite

Salinisation of agricultural soils poses an important constraint to sustainable agricultural development, especially in the Huinong region of Ningxia, northwestern China, where salinised soils are widely distributed. However, due to the limitations of monitoring technology, the detailed situation of soil salinisation in this region is not known. Currently, the multispectral instrument (MSI) on board the Sentinel-2 satellite provides a good opportunity for monitoring soil salinity dynamics. Therefore, in this study, the feasibility of using the multispectral instrument (MSI) on board the Sentinel-2 satellite, combined with a machine learning model, to accurately monitor the soil salinity content during the spring and summer seasons was explored. And three additional red-edge bands (B5-B7) were used instead of the traditional red band (B4) to generate potential soil salinity indices. A screening method based on the PLS-VIP criterion was used to screen the spectral covariates, and three machine learning methods, namely, Random Forest (RF), Support Vector Machine (SVM) and Extreme Learning Machine (ELM), were employed to build the inverse model of soil salt content. The results showed that the Random Forest model based on Sentinel-2 imagery performed the best in the inversion with good prediction results, with R2 and RE of 0.825 and 0.207 and 0.711 and 0.271 in spring and summer, respectively.The study also revealed that soil salinity varied significantly between seasons, and was higher in spring than in summer. This result is of great significance as a guide for soil salinity monitoring and land reclamation in arid or semi-arid regions.

Monitoring the seasonal variation of groundwaterchemistry and quality assessment for agricultural and industrial purpose of Athgarh basin, India

The groundwater chemistry of a region is sensitive to climate change and to change of agricultural practice of the surrounding region. The water quality is also largely governed by the litho hydrological character of the region. Hence monitoring the hydrochemistry of the groundwater with respect to climate change is vital for detecting its suitability for irrigation of cropland and industrial use. The present study area Athgarh basin, belongs to upper Gondwana has a varied lithology. The regional scale data can be statistically related to climate change. Moreover, seasonal variation of water quality has been monitored after systematic collection of groundwater samples and their methodical physicochemical analysis. 75 water samples were collected during pre-monsoon, monsoon and post-monsoon period of 2015-2016. The quality assessment is made through the estimation of physicochemical parameters, cations and anions. Based on these analyses, the irrigational parameters like salinity hazard, sodium absorption ratio (SAR), sodium%, residual sodium carbonate (RSC), potential soil salinity (PS), magnesium ratio (MR), corrosivity ratio (CR) and permeability index (PI) were calculated to determine the suitability of groundwater for irrigational and industrial purpose. The groundwater falling under (Doneen’s) class-II is almost good for irrigation purpose whereas groundwater falling under class-III indicates poor water quality. The groundwater samples are excellent to good as per Wilcox diagram. From Gibb’s diagrams, it can be established that the groundwater of the study area is mainly dominated by the lithology of aquifer of the concerned region.Various classifications show that present status of groundwater is suitable for irrigation purpose, except few locations, with a caution that it may deteriorate in near future

Seasonal impoundment alters patterns of tidal wetland plant diversity across spatial scales

AbstractUnderstanding patterns of biodiversity is a key goal of ecology and is especially pressing in the current human‐caused biodiversity crisis. In wetland ecosystems, human impacts are centered around hydrologic manipulation including the common practice of wetland diking and impoundment. Constraining how wetland management influences plant biodiversity patterns across spatial scales will provide information on how best to modify actions to preserve biodiversity and ecosystem function in managed wetlands. Here, we compare patterns of plant diversity and species presence, abundance, and community composition at several spatial scales among tidal wetlands along an estuarine salinity gradient and managed wetlands that were formerly tidal. Managed impounded wetlands had decreased alpha and gamma diversity of rare species, with less than 60% of the species richness found in tidal brackish wetlands at several spatial scales. There was little change in the overall pattern of alpha, beta, and gamma diversity for common species in impounded wetlands; however, dominant tidal brackish species, primarily perennial rhizomatous graminoids, were replaced with management target plants and non‐native annual grasses in impounded wetlands. This species replacement led to over 60% of impounded sites being classified as containing novel plant assemblages. An additional 25% of impounded sites were classified as containing tidal saline plant assemblages, suggesting potential soil salinization. Along the estuarine gradient, patchiness and codominance of common plant species drove high diversity and turnover in tidal brackish wetlands, while it remains unclear whether tidal fresh or brackish wetlands maximize rare plant diversity. With reduced species richness, altered functional dominants, and novel or saline assemblages, impounded brackish wetlands may require careful water management to balance native plant biodiversity, associated ecosystem processes, and waterfowl requirements.

GROUNDWATER QUALITY MODELING FOR SUITABILITY FOR IRRIGATION PURPOSES IN OIL PRODUCING AREAS OF KHANA AND GOKANA LOCAL GOVERNMENT AREAS OF RIVERS STATE, NIGERIA

This study is aimed at modeling groundwater quality for irrigation purposes in oil producing areas of Khana and Gokana Local Government areas of Rivers State, Nigeria. A random sampling approach was adopted in groundwater sampling in Khana and Gokana local government areas of Rivers State. Groundwater samples were collected from a total of twenty-two (22) boreholes in the area. Ten (10) residential boreholes were sampled in Khana while 12 boreholes were sampled in Gokana local government area. Various indices were used to determine the quality of groundwater for irrigation in the study area such as Electrical Conductivity (EC), Sodium Adsorption Ratio (SAR), Permeability Index (PI), Percent Sodium (%Na), Magnesium Adsorption Ratio (MAR), Kelly’s Ratio (KR) and Potential Soil Salinity (PS). In Khana area, all the water samples have PI values which render the groundwater unsuitable for irrigational purposes. Meanwhile, in Gokana, the groundwater samples show good to excellent quality for irrigation purposes. A high permeability index enhances crops yield, because the soils becomes more aerated and allows flow to occur easily, carrying plant nutrients from one part of the soil to the other. All groundwater samples in the area plotted in the C1-S1 (low sodium hazard and low salinity), C2-S1 (low sodium hazard and moderate salinity) and C3-S1 (low sodium hazard and high salinity) category which represents low sodium hazard and low salinity hazards and are therefore suitable for irrigation.

Hydro-geochemical classification and spatial distribution of groundwater to examine the suitability for irrigation purposes (Golestan Province, north of Iran)

One of the most important agricultural areas in Iran is Golestan Province. In this study, the suitability of groundwater for irrigation purposes was assessed. To determine hydro-geochemical classification of the station and assessment of spatial modeling of the study area, 12 groundwater stations were selected and an average of the last 5 years of sampling (2011–2015) has been considered. Suitability of groundwater for irrigation was assessed based on Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Na%, Permeability Index (PI), Magnesium Adsorption Ratio (MAR), Kelley’s Ratio (KR), Corrosion Ratio (CR), Residual Sodium Carbonate (RSC), Potential Soil Salinity (PSS), Chloro-Alkaline Indices (CAI), Meteoric genesis (Met. gen) and Wilcox classification. The abundance of major ions followed a HCO3 > SO4 > Na > Ca > Mg > Cl > K trend. CAI results indicate reverse cation exchange for this area, and Wilcox classification indicates that only Kalou, Kafshgari, and Kia stations are appropriate for irrigation. The spatial distribution of groundwater quality demonstrates a decreasing trend from SE to NW based on CAI, Cl, CR, EC, TSS, and TDS and shows reverse trends for KR, MAR, Met. gen, Mg/Ca, Na%, pH, PI, and RSC. In addition, the results of hydro-geochemical classification of irrigation parameters have categorized the irrigation water of this area into three different classes. Based on EC, MAR, Mg/Ca, Cl and CR, this area is suitable, but based on PSS, KR, and TH, all stations are unsuitable and according to SAR, TDS, Na% and PI, this area’s groundwater is moderate.

Chemical suitability of groundwater for irrigation in Trimohoni and Sagardari union, Keshabpur Upazila, Jessore, Bangladesh

The paper intends to provide guidance to evaluate and identify a standard ground water chemistry data for irrigation in south western region of Bangladesh. During the course of hydrogeological studies in the study area, twenty water samples were collected from twenty different villages and chemically analyzed. The analytical results revealed that the water was slightly acidic to slightly alkaline (pH 6.68 - 7.32) and TDS values range from 565 to 1073 mg/l. The other parameters like sodium adsorption ratio, (SAR) (0.10 - 0.27), sodium percentage (3.22 - 7.13), residual sodium carbonate, (RSC) (3.2 - 5.33) and potential soil salinity, (PS) (less than 30) were below the desired limit suggesting the suitability for irrigation purpose. Considering SAR, permeability index and salinity hazard, all waters could be applied safely for irrigation without any hazard to crops.Bangladesh J. Sci. Res. 27(2): 121-131, December-2014

Water quality monitoring of selected dug wells of central India with special

Dug wells water is frequently used for irrigation of crops in India. The huge quantity of various toxic pollutants enters to ground water through anthropogenic and geogenic sources, which make the ground water, unfit for irrigation. Such water if used for irrigation may pose a serious risk to quality and quantity of crops and other things. The present study highlights the water quality monitoring of selected dug wells of Central India (Rajaula ward of Chitrakoot town). Different water quality parameters such as pH, electrical conductivity, Ca ++ , Mg ++ , Na + , K + , HCO 3 − , CO 3 − - chloride, sulfate, sodium percentage (Na %), magnesium hazards, sodium absorption ratio (SAR), residual sodium carbonate (RSC), potential soil salinity and permeability index were investigated for monitoring of t0 assess its suitability for irrigation. Some models, i.e. Wilcox Diagram, U.S. Salinity diagrams, Doneen criterion, etc. were also used for conformation of dug well water quality for irrigation purpose. Results of the study indicated that all selected wells have mostly medium and high salinity, under limit of SAR, medium Na%, medium Mg hazards, under limit of RSC and low Cl − quantity.

Assessing soil salinity hazard in cultivated areas using MODFLOW model and GIS tools: A case study from the Jezre’el Valley, Israel

A high water table and soil salinization processes are common in irrigated fields in the Jezre’el Valley of Israel. This valley, located in the Lower Galilee in the northern part of the country, covers nearly 300km2. In general, salinization is accelerated when a field is underlain by a shallow, semi-confined aquifer exerting upward hydraulic pressure, which impedes drainage of the overlying soil layers. Owing to its hydrological setting, the Jezre’el Valley has inherent drainage problems, which were aggravated in the 1960s by the introduction of intensive irrigated farming. The water table rose, leading to soil salinization problems. By 1989, 1500ha showed soil salinity problems and by 1991, an area of 3300ha was affected by salinity. In this study, the MODFLOW groundwater flow model was used to simulate groundwater levels in the Jezre’el Valley. Geo-database and ArcGIS techniques were used for model input of the required dates, spatial analysis of the model results, and assessment of areas under soil salinity hazard, based on two hydrogeological criteria: (1) groundwater table depth from the soil surface and (2) difference between groundwater levels in the upper soil layer and semi-confined aquifer. It was found that the total area with intensive soil salinization is 325ha, and that with potential soil salinization 6275ha. With the appropriate input, a spatially distributed groundwater flow model such as MODFLOW can provide reliable information for the planning of an effective subsurface drainage system to prevent soil salinization.

Field Study of Salt Balance of a Land Application System

Wastewater land application is a cost-effective method to treat and dispose wastewater; however, it may cause soil salinization. Salt mass balance and the potential soil salinization caused by the wastewater land application were investigated in the crop root zone in a wastewater land application system at the City of Littlefield, TX, USA from October 7, 2005 to September 28, 2007 using a lysimeter system. This study showed that, after 2 years of wastewater land application, the ranges of soil salinity were still lower than the threshold (8,500 μS/cm) for Bermuda grass assuming a 10% yield reduction. The leached salt mass showed large spatial and temporal variation. The average values of electrical conductivity of the saturated paste extract of the soil samples increased from 1,433 μS/cm in June 2006 to 1,840 μS/cm in June 2007. The average values of the soil sodium adsorption ratio between June 2006 and June 2007 increased from 11 to 14 resulting in a potential risk of soil dispersion and decreasing the soil infiltration rate. Although the measured leaching fractions in nearly all sampling periods, except one, were higher than the leaching requirement, salt accumulations in the root zone were still found with only two exceptions. Since the time required for reaching equilibrium between cumulative salt mass input and cumulative salt mass output varies from 1 year to a few years, or even longer, the long-term investigation is recommended for the study of salt mass balance in the root zone of this wastewater land application system.

Groundwater table and salinity: Spatial and temporal distribution and influence on soil salinization in Khorezm region (Uzbekistan, Aral Sea Basin)

Groundwater (GW) management is an essential element in irrigated agriculture. This paper analyzes the temporal dynamics of GW table and salinity in Khorezm, a region of Uzbekistan which is situated on the lower Amu Darya River in the Aral Sea Basin and suffering from severe soil salinization. We furthermore identify the critical areas for potential soil salinization by examining GW table and salinity measured during 1990–2000 in 1,972 wells, covering the entire region. Additionally, case studies were performed to assess the contribution of the GW to the soil salinization on a field scale. Over the entire area, GW was only moderately saline averaging 1.75 ± 0.99 g l−1 However, GW levels were generally very shallow averaging 148 ± 57 cm below the ground surface and thus likely to prompt secondary soil salinization. Three case studies where GW table, soil and GW salinity were closely monitored at the field scale, suggested that the elevated GW levels forced soil salinization by annually adding 3.5–14 t ha−1 of salts depending on the position and salinity of the GW table. Maps interpolated from the regional dataset revealed that GW was significantly shallower and more saline in the western and southern parts of Khorezm despite the presence of a drainage network which is rather uniformly distributed throughout the region. The results of the current study will assist the development of an improved drainage management in Khorezm.