Use Of Marginal Quality Water Research Articles

Review: Modeling the Effects of Salinity and Sodicity in Agricultural Systems

AbstractSoil salinity and sodicity are major concerns in agricultural systems, threatening plant growth in the short term and soil health in the long term. Despite these risks, use of marginal quality water with high salt concentrations is often essential to maintaining food production, especially in arid and semi‐arid regions. Leveraging our understanding of basic soil processes and feedbacks is essential for ensuring sustainable use of marginal quality water and land. Models are an important component in effective management, since they allow us to investigate large numbers of potential future scenarios, augmenting our ability to predict the consequences of agricultural practices. In this review, we examine the most advanced models for studying the effects of salinity and sodicity on plant health and soil structure. We place special emphasis on the integration of these frameworks into dynamical models, which can be used to examine how changing climate and irrigation conditions lead to evolving plant and soil responses over time. We highlight important differences in existing modeling frameworks, especially with regard to their relative complexity and suitability for integration into larger climate models. We overview important applications of these models, including studies of localized leaching of salts, complex ion chemistry, the dynamics in layered profiles, and the risk of long‐term soil degradation as a result of particular irrigation practices.

Response of Potted Hebe andersonii to Salinity under an Efficient Irrigation Management

Although the use of marginal-quality water can be an effective measure to alleviate water scarcity, it often contains a high concentration of salts that can compromise crop growth. As a result, farmers apply more water than necessary to leach salts away from the root zone, resulting in wasted water and the release of fertilizers into the groundwater. In this study, we assessed the effects of three salinity levels of irrigation water (1.8 dS m−1, 3.3 dS m−1, and 4.9 dS m−1) on the physiology and ornamental traits of Hebe andersonii cv. Variegata. The experiment was carried out with potted plants in a greenhouse for seven months. We also studied the feasibility of growing this cultivar without leaching salts. The results showed that Hebe plants can be grown without leaching using water up to 3 dS m−1. This setup produces plants with high water use efficiency and without reducing their ornamental value. Meanwhile, irrigation with 5 dS m−1 water reduced the quality of Hebe but did not compromise its physiological processes. The photosynthesis of Hebe under salinity conditions was mainly controlled by stomata, which was related to the level of salt stress and water status of the plant. Salinity had no significant effects on photosystem II, which can be explained by the fact that Hebe was able to dissipate the excess excitation energy as heat effectively. Hebe was able to avoid ion toxicity and maintain a suitable nutrient balance under the salinity levels tested in this experiment.

Towards Sustainable Application of Wastewater in Agriculture: A Review on Reusability and Risk Assessment

The use of marginal-quality waters, not limited to brackish/saline and treated sewage effluent (TSE), is called reclaimed water. Reclaimed water is a sustainable source in the future for use in agriculture, essentially required to offset the food demand of a rapidly growing population. Moreover, the sustainable recovery of reclaimed water is essential for humanity to satisfy extreme sanitation and water-supply demands. To increase access to water supply, alternate water resources’ use, existing water resources’ degradation, and improved water-use efficiency are imperative. There is a high potential to address these factors by using reclaimed water as an alternative source. The reclaimed water treated at a tertiary level has the potential for use in crop production, especially for forage crops, irrigating urban landscapes, recreational and environmental activities, industry, and aquifer recharge to increase strategic water reserves in water-scarce countries. This way, we can save precious freshwater that can be utilized for other purposes. Eminently, freshwater applications for industrial and agronomic sectors account for 20% and 67%, respectively, depleting freshwater resources. The use of reclaimed water in agriculture can significantly reduce pressure on freshwater. However, if the quality of reclaimed water does not comply with international standards, it may cause serious health risks (diseases) and soil pollution (heavy metals).

Physiological and biochemical responses of mini watermelon irrigated with brackish water under two types of irrigation system

the use of marginal quality water can be a viable alternative in regions with water scarcity when associated with an adequate irrigation management strategy. The aim of this study was to evaluate the physiological and biochemical responses of ‘Sugar Baby’ mini watermelon as a function of irrigation management and salinity of the nutrient solution (ECsol). The experiment was carried out in a greenhouse of the Federal University of Recôncavo of Bahia, in the municipality of Cruz das Almas - BA, in a completely randomized design, with four replications. The plants were grown under two types of irrigation management (conventional drip - CD and pulse - PD) and four saline levels of the fertigation nutrient solution (2.5 - control; 4.5; 5.5; 6.5 dS m-1). At 65 days after cultivation, the following variables were evaluated: chlorophyll a and b content, chlorophyll a fluorescence, and organic and inorganic solutes content. The treatments did not influence the levels of chlorophyll a and b. Salinity decreased the quantum yield of photochemical energy conversion due to the increased quantum yield of unregulated energy loss. Irrigation management and water salinity did not affect carbohydrate content in mini watermelons leaves. However, soluble proteins were higher in the CD than in PD and decreased with increasing salinity in both managements. Salinity increased free amino acids in CD but did not change the content of these solutes in PD. Free proline was only influenced by the management system and was higher in CD than in PD. Sodium, chloride, and sodium to potassium ratio increased with ECsol, but these increases were more pronounced in PD. Salinity increased potassium content in PD and reduced in CD. The CD led to lower absorption of toxic ions, reducing the effects of salinity on the mini watermelon.

Reassessing irrigation water quality guidelines for sodicity hazard

Current irrigation water quality guidelines for sodicity hazard, in use since the 1980s, are based on assessments of salinity (Electrical conductivity, EC) and sodicity (Sodium Adsorption Ratio, SAR), where SAR considers the positive effects of calcium (Ca) and magnesium (Mg) against the adverse effects of sodium (Na) on soil permeability. Recent research and practice, however, have provided ample evidence for negative effects of both potassium (K) and Mg on soil physical properties in addition to Na. This paper (1) discusses a proposed irrigation water quality parameter which generalizes SAR by including the Potassium Adsorption Ratio (PAR) along with two adjustable numerical coefficients for the K and Mg concentrations to reflect their role as dispersive cations; (2) discusses the tradeoffs from including K and the complex effects of Mg in irrigation water quality assessment; (3) analyzes water quality using the new parameter for 600 water samples from irrigated regions around the world; and (4) proposes revised irrigation water quality guidelines for assessing soil permeability hazard, a generalization of sodicity hazard. Revising current irrigation water quality guidelines in this way will help practitioners assess the suitability of a given water more accurately and will guide fit-for-purpose options and associated management strategies to ensure the sustainability of irrigated agriculture as the use of marginal-quality waters increases to meet the challenge of freshwater scarcity.

Towards predicting the soil-specific threshold electrolyte concentration of soil as a reduction in saturated hydraulic conductivity: The role of clay net negative charge

The use of marginal quality water with saline and dispersive properties is set to become more prevalent in agricultural production given demands on freshwater resources. The threshold electrolyte concentration (CTH) is often used to define the suitability of such water, with irrigation practitioners seeking a general predictive model based on soil order. Recent work supports that the CTH absolute value is soil-specific, although there remains a requirement to identify the contribution of predictive factors in an effort to create a predictive function for the CTH. This work used 58 soils to explore the variability of the CTH within and between soil orders, subsequently comparing saturated hydraulic conductivity to leachate turbidity as a means to investigate CTH existing prior to the point of spontaneous dispersion. The role of clay net negative charge was investigated in terms of its relation to the CTH in an effort to move towards a predictive capacity for this soil-specific characteristic. Subsequently, it was demonstrated that the CTH was apparently described by net negative charge of clay particles, suggesting that surface interactions between clay particles and the bulk solution are important in governing soil stability from a soil-specific point of view The CTH occurred prior to the aggregate–dispersion threshold and was clearly soil-specific, even within a soil order. Future work is required to incorporate the ionisation potential and clay domain pressure models of soil stability to move towards a CTH predictive function based on quantified differences in soil mineralogy and charge characteristics, which is discussed.

Analytical steady‐state solutions for water‐limited cropping systems using saline irrigation water

AbstractDue to the diminishing availability of good quality water for irrigation, it is increasingly important that irrigation and salinity management tools be able to target submaximal crop yields and support the use of marginal quality waters. In this work, we present a steady‐state irrigated systems modeling framework that accounts for reduced plant water uptake due to root zone salinity. Two explicit, closed‐form analytical solutions for the root zone solute concentration profile are obtained, corresponding to two alternative functional forms of the uptake reduction function. The solutions express a general relationship between irrigation water salinity, irrigation rate, crop salt tolerance, crop transpiration, and (using standard approximations) crop yield. Example applications are illustrated, including the calculation of irrigation requirements for obtaining targeted submaximal yields, and the generation of crop‐water production functions for varying irrigation waters, irrigation rates, and crops. Model predictions are shown to be mostly consistent with existing models and available experimental data. Yet the new solutions possess advantages over available alternatives, including: (i) the solutions were derived from a complete physical‐mathematical description of the system, rather than based on an ad hoc formulation; (ii) the analytical solutions are explicit and can be evaluated without iterative techniques; (iii) the solutions permit consideration of two common functional forms of salinity induced reductions in crop water uptake, rather than being tied to one particular representation; and (iv) the utilized modeling framework is compatible with leading transient‐state numerical models.

Use of Marginal Quality Waters for Irrigation

CSA NewsVolume 59, Issue 6 p. 17-17 Science Use of Marginal Quality Waters for Irrigation First published: 03 June 2014 https://doi.org/10.2134/csa2014-59-6-6Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume59, Issue6June 2014Pages 17-17 RelatedInformation

Global Sensitivity Analysis for UNSATCHEM Simulations of Crop Production with Degraded Waters

One strategy for maintaining irrigated agricultural productivity in the face of diminishing resource availability is to make greater use of marginal quality waters and lands. A key to sustaining systems using degraded irrigation waters is salinity management. Advanced simulation models and decision support tools can aid in the design and management of water reuse systems, but at present model predictions and related management recommendations contain significant uncertainty. Sensitivity analyses can help characterize and reduce uncertainties by revealing which parameter variations or uncertainties have the greatest impact on model outputs. In this work, the elementary effects method was used to obtain global sensitivity analyses of UNSATCHEM seasonal simulations of forage corn (Zea mays L.) production with differing irrigation rates and water compositions. Sensitivities were determined with respect to four model outcomes: crop yield, average root zone salinity, water leaching fraction, and salt leaching fraction. For a multiple‐season, quasi‐steady scenario, the sensitivity analysis found that overall the most important model parameters were the plant salt tolerance parameters, followed by the solute dispersivity. For a single‐season scenario with irrigation scheduling based on soil water deficit, soil hydraulic parameters were the most important; the computed salt leaching fraction was also strongly affected by the initial ionic composition of the exchange phase because of its impact on mineral precipitation. In general, parameter sensitivities depend of the specifics of a given modeling scenario, and procedures for routine use of models for site‐specific degraded irrigation water management should include site‐specific uncertainty and sensitivity analyses. The elementary effects method used in this work is a useful approach for obtaining parameter sensitivity information at relatively low computational cost.

ADAPTING TO CLIMATE CHANGE BY IMPROVING WATER PRODUCTIVITY OF SOILS IN DRY AREAS

ABSTRACTConsidering extreme events of climate change and declining availability of appropriate quality water and/or highly productive soil resources for agriculture in dryland regions, the need to produce more food, forage and fibre will necessitate the effective utilization of marginal‐quality water and soil resources. Recent research and practices have demonstrated that effective utilization of these natural resources in dry areas can improve agricultural productivity per unit area and per unit water applied. This paper focuses on the following three case studies as examples: (1) low productivity soils affected by high levels of magnesium in soil solution and on the cation exchange complex; (2) degraded sandy soils under rainfed conditions characterized by low water‐holding capacity, organic matter and clay content and (3) abandoned irrigated soils with elevated levels of salts inhibiting growth of income generating crops. The results of these studies demonstrate that application of calcium‐supplying phosphogypsum to high‐magnesium soils, addition of clays to light textured degraded soils and phytoremediation of abandoned salt‐affected soils significantly improved productivity of these soils. Furthermore, under most circumstances, these interventions were economically viable, revealing that the efficient use of marginal‐quality water and soil resources has the potential to improve livelihoods amid growing populations in dry areas while reversing the natural resource degradation trend. However, considerably more investment and policy‐level interventions are needed to tackle soil degradation/remediation issues across both irrigated and dryland agricultural environments if the major challenge of producing enough food, forage and fibre is to be met. Copyright © 2011 John Wiley & Sons, Ltd.

Salinity‐related desertification and management strategies: Indian experience

AbstractHigh concentration of salts in the rootzone soil limits the productivity of nearly 953 million ha of productive land in the world. Australia, followed by Asia, has the largest area under salinity and sodicity. Most of the salt‐affected soils and brackish ground water resources are confined to arid and semiarid regions and are the causative factors for triggering the process of desertification. The problem of salinity and sodicity has degraded about 6·73 million ha area in India. Secondary salinization associated with introduction of irrigation in dry areas like Thar desert in the western part of the country and Sharda Sahayak in Central India have caused desertification due to rise of salts with the rise in ground water level. Large scale cultivation of prawns using sea water in coastal Andhra Pradesh and elsewhere rendered about 2.1 million ha area unfit for agriculture. Similarly, 30–84 per cent ground water in north‐western states of the country is either saline and /or brackish and is unfit for irrigation. Use of marginal quality water for irrigation has rendered several thousand ha of productive land unfit for cultivation. The Central Soil Salinity Research Institute was established in 1969 at Karnal to develop sustainable and eco‐friendly technologies for reclamation and management of salt‐affected soils and judicious use of marginal quality waters. The institute has developed location‐specific techniques for reversion of salinity related desertification in India. Salient findings of research during the last three decades and more are presented in this review. This paper deals with (a) classification, nature and extent of salt‐affected soils and poor quality water in India, (b) case studies/socio‐economic concerns of salinity related desertification, (c) chemical, hydrological and biological approaches in use for rehabilitation of salt‐affected soils, (d) guidelines for safe and productive use of marginal quality ground water through cyclic and mixed mode and precision irrigation techniques, (e) successful rehabilitation case studies, (f) alternate land use practices such as raising forest plantations, horticulture, agroforestry, high value medicinal, aromatic and flowering crops, etc., (g) technological, social, economic and environmental impacts and (h) future line of research. Issues requiring policy initiatives to halt salinity‐related desertification are also discussed in this review paper. Copyright © 2009 John Wiley & Sons, Ltd.

Distribution and storage characterization of soil solution for drip irrigation

The increased use of marginal quality water with drip irrigation requires sound fertigation practices that reconcile environmental concerns with viable crop production objectives. We conducted experiments to characterize dynamics and patterns of soil solution within wet bulb formed by drip irrigation. Time-domain reflectometry probes were used to monitor the distribution of potassium nitrate (KNO3) and water distribution from drippers discharging at constant flow rates of 2, 4 and 8 L h−1 in soil-filled containers. Considering results from different profiles, we observed greater solute storage near the dripper decreasing gradually towards the wetting front. About half of the applied KNO3 solution (48%) was stored in the first layer (0–0.10 m) for all experiments, 29% was stored in the next layer (0.10–0.20 m). Comparing different dripper flow rates, we observed higher solution storage for 4 L h−1, with 45, 53 and 47% of applied KNO3 solution accumulating in the first layer (0–0.10 m) for dripper flow rates of 2, 4 and 8 L h−1, respectively. The results suggest that based on the volume and frequency used in this experiment, it would be advantageous to apply small amounts of solution at more frequent intervals to reduce deep percolation losses of applied water and solutes.

Use of marginal quality water for plant production in Europe

The use of marginal quality water for plant production in Europe is analysed. The implications of using marginal quality water on plant, health and environment are reviewed. The status of current European research is outlined. On the basis of current experience, it can be concluded that marginal quality water can be safely used for plant production, provided certain precautions are taken to protect health and the environment.