A hydrologic-economic-agronomic model with regard to salinity for an over-exploited coastal aquifer

The SALTMED model performance was evaluated by comparing the simulated and measured soil water content, biomass and grain yield data of quinoa grown in a Mediterranean climate under various irrigation regimes using fresh and saline water of different qualities. The data from a two‐year field study (2010–2012) were used for this purpose. Six different treatments consisted of full irrigation with fresh and saline water with salinity levels of ECw 10, 20 and 30 dS m‐1, and deficit irrigation with fresh water applied at 50 and 75% of full irrigation and rainfed treatment were considered. Quinoa irrigated with saline water of 30 dS m‐1 resulted in significant grain yield reduction in 2010, but slightly reduced with water salinity level ranging from 10 to 30 dS m‐1 in comparison to fresh water in 2012. However, deficit irrigation with fresh water reduced plant dry matter yields considerably. The results of calibration and validation of the model showed that the SALTMED model can simulate soil water content, dry matter and grain yield of quinoa with high accuracy under various watering regimes using fresh and saline water of different qualities. Copyright © 2016 John Wiley & Sons, Ltd.

برای بررسی اثر سطوح شوری آب آبیاری و زمان شروع آبیاری با آب شور و لب‌شور بر خصوصیات کمی خربزه دیررس، آزمایشی با 7 تیمار و 3 تکرار در قالب بلوک‌های کامل تصادفی با استفاده از روش آبیاری قطره‌ای نواری، در مرکز تحقیقات کشاورزی و منابع طبیعی خراسان رضوی انجام شد. تیمارهای آبیاری عبارت بودند از: 1- آبیاری با آب شیرین (6/0 دسی‌زیمنس بر متر) از ابتدای کاشت تا انتهای فصل برداشت، 2- آبیاری با آب با شوری 3 دسی‌زیمنس برمتر از ابتدا تا انتهای فصل داشت، 3-آبیاری با آب با شوری 6 دسی‌زیمنس بر متر از ابتدا تا انتهای فصل، 4- آبیاری با آب با شوری 6 دسی‌زیمنس بر متر از 20 روز بعد از جوانه‌زنی تا انتها، 5- آبیاری با آب با شوری 3 دسی‌زیمنس بر متر از 20 روز بعد از جوانه‌زنی تا انتها، 6- آبیاری با آب با شوری 6 دسی‌زیمنس بر متر از 40 روز بعد از جوانه‌زنی تا انتها و 7- آبیاری با آب با شوری 3 دسی زیمنس بر متر از 40 روز بعد از جوانه‌زنی تا انتهای فصل داشت. نتایج نشان داد که، شوری آب بر عملکرد کل، عملکرد اقتصادی و کارآیی مصرف آب آبیاری تاثیر معنی‌داری داشت. بالاترین عملکرد کل و عملکرد اقتصادی و کارآیی مصرف آب آبیاری از تیمار شاهد بدست آمد که تفاوت آن‌ها با تیمارهای آب شور و لب‌شور معنی‌دار بود. در ضمن تفاوت بین عملکردهای تیمارهای شور و لب‌شور معنی‌دار نبودند. آبیاری با آب شیرین در اوایل دوره رشد باعث افزایش محصول نشده بلکه، باعث وارد شدن تنش بیشتر به گیاه می‌شود.

SUMMARYYield responses of a grain amaranth accession to different irrigation strategies were evaluated in Naples, Italy. Field experiments were carried out to evaluate the quantitative and qualitative response of amaranth under combined abiotic stresses (salinity and drought) in a Mediterranean environment of South Italy affected by problems due to groundwater salinization from seawater intrusion.A comparison was made in 2009 and 2010 between a fully irrigated treatment (1·00), with the restitution of all of the water necessary to replenish to field capacity the soil layer explored by roots (0·00–0·36 m), and two treatments with restitution of 0·50 and 0·25 of the water volume used for the fully irrigated treatment. The three levels of irrigation volume were combined with two levels of salinity, either fresh or salt water, with electrical conductivity (EC) of the irrigation water of 0·64 and 22 dS/m respectively, in a factorial experiment thus harbouring six treatments in a randomized complete block design. The results showed good adaptation of amaranth to drought. It was possible to obtain high yields even if groundwater with infiltrated seawater was used for irrigation (50% yield reduction when the EC of soil saturated paste extract (ECe) was 13·97 dS/m). A reduction of 50% in the volume of irrigation did not cause a significant reduction in yield, whether using fresh or saline water, compared to the treatment fully irrigated with fresh water. The chemical composition of amaranth seeds, however, was significantly affected by the treatments. Starch and ash content decreased with increasing drought while protein content was increased by both salt and drought.In view of the increased presence of salinity and drought stress in the Mediterranean area and the scarce information on amaranth response to salt and water stress, the aim of the present work is evaluation of the quantitative and qualitative response of amaranth grown in a Mediterranean environment of South Italy under combined drought and salinity stress.

Increased demands for freshwater in irrigated agriculture might be offset in some instances by substituting saline waters when they are available. The purpose of this paper is to present a quantitative method for determining the optimal mix of saline and nonsaline waters for crop production. Equal yield curves (isoquants), which quantify the extent of substitutability between waters of different qualities when constant yield is sought, were derived from crop‐water production functions for waters of different qualities computed from a previously published model. Isoquants were derived for several crops for relative yield (RY) values of 1.0, 0.9, and 0.8. The waters considered for mixing were nonsaline waters and waters of electrical conductivity (EC) equal to 4, 6, or 11 dS/m. Extending the supply of water by combining nonsaline and saline water is not always technically or economically feasible, and depends on specific crop and water pricing situations. The technical and economic feasibility of mixing waters of different quality increases as the EC of the saline water decreases, crop tolerance to salinity increases, desired RY decreases, or the relative price of saline to nonsaline water decreases.

چکیده کیفیت آب آبیاری در اکثر مناطق ایران پائین بوده و به درجات مختلف با شوری همراه می‌باشد که بروز خشکسالی این مشکل را تشدید کرده است. با اعمال مدیریت‌های صحیح کشاورزی می‌توان از این آبها برای کشت گیاهان متحمل و نیمه متحمل به شوری استفاده کرد. یکی از روش‌های مدیریتی جهت استفاده از آب‌های شور و لب‌شور، تلفیق آب شور و معمولی می‌باشد. هدف این تحقیق، بررسی چهار روش تلفیق آب شور (هدایت الکتریکی 11 دسی زیمنس بر متر) و معمولی (هدایت الکتریکی 2 دسی زیمنس بر متر) و تأثیر هر رژیم روی عملکرد و اجزای عملکرد دو رقم آفتابگردان بود. آزمایش به صورت کرت‌های خرد شده در قالب طرح بلوک کامل تصادفی با 4 تکرار اجرا گردید که در آن کرت‌های اصلی شامل 2 رقم آفتابگردان ( هایسان 33 و آلستار) بوده و در کرت‌های فرعی از 4 رژیم آبیاری (1ـ تیمار شور ـ معمولی، 2ـ تیمارآب معمولی ـ شور، 3ـ آبیاری یک در میان و 4ـ آبیاری مخلوط) استفاده شد. بذر هر دو رقم هایسان 33 و رقم آلستار، به طور مساوی در 32 کرت کاشته شده و از مرحله‌ی کاشت تا ساقه‌دهی گیاهان، سه مرتبه با آب معمولی جهت استقرار بهتر آبیاری شدند. بعد از این مرحله تا زمان برداشت برای آبیاری، رژیم‌های آبیاری مورد اشاره به کار گرفته شد. نتایج نشان داد که در میان چهار رژیم اعمالی، رژیم آبیاری شور ـ معمولی از نظر عملکرد روغن، وزن صد دانه، عملکرد دانه، عملکرد دانه در طبق، قطر ساقه، ارتفاع بوته، قطر طبق، مساحت برگ و املاح موجود در برگ بیشترین شاخص را داشته است. برای رقم هایسان 33 رژیم آبیاری یک در میان و برای رقم آلستار رژیم آبیاری مخلوط بعد از رژیم آبیاری شور ـ معمولی دارای بهترین عملکرد دانه و روغن بوده است. واژه های کلیدی: شوری، مدیریت آبیاری تلفیقی، آفتابگردان، عملکرد

Salinity in soil and irrigation water is a major environmental stress in arid and semi-arid regions affecting soil organic carbon and its pools. A pot experiment was carried out in India to investigate distribution of soil carbon and its dynamic pools and nutrients under saline water irrigation in seed spice crops. Soil samples were analyzed for physicochemical properties (pH1:2, EC1:2), soil carbon (inorganic and organic), its pools (vey labile, labile, less labile and non-labile), and soil nutrients. Soil pH and EC varied between 7.70–8.72 and 0.45–8.25 dS m−1, respectively. Soil organic carbon and total soil carbon were higher by 15.2 and 22.4% with alternate application of saline and fresh water compared with continuous application of saline or fresh water and increased the less labile and non-labile carbon pools. Alternate application of saline and fresh water increased both the active and passive pools of carbon. Calcium carbonate and inorganic carbon were decreased by 35% with the continuous application of saline and fresh water. Similarly, alternate application of saline and fresh water increased carbon stock, carbon management index, and carbon pool index compared with sole application of fresh or saline water. Available nitrogen, phosphorous, and potassium varied from 310 to 629 kg ha−1, 39 to 87 kg ha−1, and 87 to 430 kg ha−1, respectively. Micronutrients were found to be highest with alternate application of saline and fresh water. Zinc, iron, manganese, and copper varied from 2.66 to 5.24, 2.64 to 6.67, 4.60 to 13.07, and 1.36 to 3.66 mg kg−1 soil, respectively. Alternate application of saline and fresh water helps in the build-up of soil carbon while maintaining the soil nutrient pools compared to sole application of saline or fresh water application.

A pot experiment was conducted to study the effects of conjunctive use of saline and fresh water on the growth and biomass of cotton crop and to observe varietal variability for salinity tolerance and ion contents of cotton genotypes. Four cotton genotypes (Sindh-1, BT-121, CRISS-494, CRISS-588) were irrigated with four treatments, C1 (control+ tape water), C2 (EC 4.0 dS m-1, throughout growth period), ( (six irrigation with C2 + six irrigation with C1), C3 (EC 8.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C3), (six irrigation C3+ six irrigation C1), C4 (EC 12.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C4). The results showed that highest fresh biomass, plant height, number of leaves plant-1, number of bolls and boll weight was obtained in the treatment where tape water was used. Whereas, these parameters were decrease significantly with the increasing salinity levels from 4 to 12 dS m-1 and when saline water was applied continuously throughout growth period. The cotton genotypes Sindh-1 and Bt-21 performed well under conjunctive use of saline and fresh water with maximum values in compare to genotypes CRIS 494 and 588. The Na+ and Cl- accumulation in cotton leaves and in soil significantly increased with rising EC levels of irrigation water. However, Na+ and Cl- contents were found more in CRIS 494 and CRIS 588 than Sindh-1 and Bt1. It is concluded that Sindh-1 and Bt-121 may be cultivated in saline areas with alternate irrigation.

Aquifers along the coastal regions around the world are facing severe level of saline water intrusion problems. Rapid development and the associated increase in groundwater withdrawals intensify the problem. Extensive mapping of migration and extent of salt water plumes is difficult and costly. Several surficial geophysical methods have been developed for measuring salinity levels in coastal aquifers. The present study is an attempt to delineate the saline water and fresh water intrusion in parts of west coast of Maharashtra, India. A total of 86 vertical electrical soundings were carried out using the Schlumberger configuration. The contour maps for Dar-Zarrouk parameters viz. the transverse resistance (T), longitudinal conductance (S), and coefficient of anisotropy (λ) were computed at 84 sites to generate the resistivity regime of saline and fresh water bearing formations. The results exemplify that the Dar-Zarrouk parameters provide a practical elucidation in demarcating the saline and fresh water aquifers, particularly when the resistivity data interpretation encounters constraints due to intermixing of saline water aquifers, fresh water aquifers etc. Several NE-SW and NW-SE oriented major lineaments and its cris-crosses have been observed in this region.

Using of saline water for irrigation of crops is known as a strategy of on-farm irrigation water management. In this study, the cyclic using of saline and fresh water and its effect on soil salinity were investigated. Field experiments were carried out in randomized complete block design under drip irrigation for maize crop with 9 treatments. The treatments were based on alternative irrigation management of saline and fresh water use on three salinity levels 0.4, 3.5 and 5.7 dS/m and freshwater application in every one, three and five saline water application (1:1, 3:1 and 5:1, respectively). The results showed that in 1:1 management, soil salinity at the end of growing season compared with the beginning of growing season did not change considerably (reducing of 1.0% and 17.9% for 1S1:1F and 1S2:1F). In 3S2:1F and 5S2:1F treatments, the amount and frequency of fresh water was not enough to remove salts from the soil and at the end of growing season, salt accumulation was seen in soil profile (increasing of 39.0% and 46.2% in soil salinity). In 3S1:1F and 5S1:1F treatments, soil salinity increased 17.9% and 31.6%, respectively, while increasing of soil salinity in S1 treatment was 40.7%. Thus, by 4 irrigations with fresh water in 3S1:1F treatment and 2 irrigations with fresh water in 5S1:1F treatment, reducing of 22.8% and 9.1% in soil salinity was seen in compared with S1 treatment.

Guilan, a well-known province in rice production in Iran, has been facing water shortage and water degradation. In order to study the effects of salinity stress as well as water stress on rice a pot experiment was conducted at Rice Research Institute of Iran. Five water salinity levels: fresh water (EC = 1 dS m-1), 2, 4, 6 and 8 dS m-1 and five irrigation regimes: continues flooding, Alternative Wetting and Drying (AWD), intermittent irrigation at 100, 90 and 80 percent of field capacity (FC) were considered as irrigation treatments. The results showed severe effects of water and salinity stresses on rice yield and yield components. Fresh water produced the highest yield, 18.57 gr pot-1, whereas, the yield in salinity levels of 2, 4, 6 and 8 dS m-1 were 13.78, 5.78, 3.61 and 0.74 gr pot-1, respectively, with the yield losses of 25, 70, 80 and 97%, respectively. Intermittent irrigation at FC produced the highest yield. The yield increased 8 and 13% in AWD and intermittent irrigation at FC treatments respectively, while it decreased 8 and 27% in intermittent irrigation at 80 and 90% of FC treatments as compared with continues flooding treatment. The highest yield with application of intermittent irrigation at FC was valid only in water salinity less than 4 dS m-1. When water salinity was higher than 4 dS m-1 all irrigation methods gave the same yield. This study showed that the best method to use saline water was intermittent irrigation at FC with EC = 2 dS m-1. In case of more salinity, mixing fresh and saline water and intermittent irrigation can mitigate the severe effects of salinity on rice.

Salt water intrusion is a key issue in dealing with exploitation, restoration, and management of fresh ground water in coastal aquifers. Constant monitoring of the fresh water-salt water interface is necessary for proper management of ground water resources. This study presents a simple method to estimate the depth of the fresh water-salt water interface in coastal aquifers using two sets of pressure data obtained from the fresh and saline zones within a single borehole. This method uses the density difference between fresh water and saline water and can practically be used at coastal aquifers that have a relatively sharp fresh water-salt water interface with a thin transition zone. The proposed method was applied to data collected from a coastal aquifer on Jeju Island, Korea, to estimate the variations in the depth of the interface. The interface varied with daily tidal fluctuations and heavy rainfall in the rainy season. The estimated depth of the interface showed a good agreement with the measured electrical conductivity profile.

Limited freshwater resources and climatic change are major challenge face animal production industry, especially in the arid and semiarid regions. Climate changes are reflected in global warming and rainfall reduction, which in turn may increase the salinity of both soil and water. Within the reclamation strategy, groundwater will be the main source of used water in cultivated desert lands in Egypt. However, the groundwater has high salinity and the cost of desalination is expensive. This review gives an overview of the impact of using saline water as an alternative source of fresh water to avoid water scarcity effect on the performance, carcass traits, and meat quality of farm animals. The ability of animals to tolerate saline water depends on the animal species, salinity level and the type of salt minerals in water. Some studies indicated that the animals' performance improved in low levels of salinity, but the performance decreased when the salinity levels was increased. In conclusion, this study implies that the saline water containing high concentrations of minerals mainly sodium chloride can largely affect the livestock productive aspects.

The analysis of salt production by a recrystallization method using the concentrated backflow effluent of the desalination units

In this study, molecular oscillation technology (Merus ring), developed to prevent calcification, biofilm formation and corrosion in piping in industrial water treatment systems, was compared as an alternative to acid injection to prevent the clogging of emitters by chemicals, and fresh and saline water were compared on the basis of system performance parameters (coefficient of variation, distribution uniformity, Christiansen uniformity, emission uniformity) and economic aspects. The results revealed that both acid injection and the Merus ring in saline and fresh water resulted in significantly higher average emitter flow rates than the control treatment. Both the Merus ring and the acid injection achieved higher performance parameters with fresh water than with saline water. Acid injection was found to be more effective in preventing clogging of the emitters than the Merus ring when saline water was used. Compared with fresh water, saline water increases emitter clogging. The economic analysis revealed that the Merus ring was more economical ($204.3 ha−1) than acid injection with both fresh water ($318.2 ha−1) and saline water ($578.6 ha−1). Therefore, the Merus ring could be a reliable and environmentally friendly alternative to acid injection to prevent the clogging of emitters in drip systems when saline water is used.

Salinity levels and drought status of coastal wetlands may be strongly affected by climate change, and changes in the nitrogen cycle of mangrove wetlands may also be affected. We established combinations of three salinity and water levels with applied stable isotope 15N to study the δ15N distributions in the sediment and plants of a greenhouse-based simulated mangrove Aegiceras corniculatum wetland system. The stable isotope 13C and 15N, C and N contents and the C:N ratio were determined. Results showed that increasing in salinity significantly increased the δ13C value in plant organs. The δ15N value of plant organs increased with increasing water level in low salinity (10‰) and medium salinity (20‰) treatment groups but not in the high salinity (30‰) treatment group. This may attributed to A. corniculatum adjusting the δ15N distribution in different organs in response to high salinity stress. Compared to the δ13C, the δ15N values of plant were strongly affected by salinity and water level treatments, indicating that the behavior of N cycle was somewhat different than the C cycle, and affected by the combined effects of both salinity and water level. Most of 15N absorbed by plant tissues were in leaves except for the highest salinity and high water level treatment, showing at increasing water level, the proportion of 15N increased in root. Overall, the measured indicators exhibited different responses to salinity level and water level, suggesting that the changes in salinity and water levels have an impact on N cycling processes of wetland systems.