Moderate Saline Water Research Articles

Girassol suplementado com percolado de aterro sanitário e submetido à salinidade

O percolado de aterro sanitário é um líquido produzido a partir de processos físicos, químicos e biológicos aos quais os resíduos sólidos urbanos são submetidos nos aterros sanitários. Apresenta uma composição físico-química variável e pode conter altos teores de nutrientes, sendo assim empregado na fertilização de plantas. Por isso, objetivou-se avaliar o crescimento de plantas de girassol irrigadas com água de moderada salinidade e com suplementação nutricional com percolado de aterro sanitário. O experimento foi conduzido em área experimental com cobertura de nylon (sombrite), sob delineamento inteiramente casualizado em um fatorial 4 x 2, sendo [1: 100% de areia de granulometria fina - NBR 6502; 2: areia + adubo/fertilizante orgânico misto (mistura de bagaço de cana, esterco bovino, esterco de galinha, serragem de madeira e gesso agrícola) e 80 kg de N ha-1, 3: areia + percolado de aterro sanitário e 80 kg de N ha-1; e 4: areia + percolado de aterro sanitário e 160 kg de N ha-1] e duas concentrações salinas da água de irrigação [irrigação com água destilada ou solução de NaCl a 60 mM], com 10 repetições, em vasos de 12 L. Foram realizadas análises de crescimento (altura, diâmetro do coleto, número de folhas), teores relativos de clorofila e diâmetro dos capítulos. Nas condições experimentais empregadas, substrato arenoso, as concentrações de percolado de aterro sanitário utilizadas promoveram incrementos em todas as variáveis de crescimento analisadas nas plântulas de girassol, especialmente a 80 Kg N ha-1. A irrigação com solução de NaCl a 60 mM não ocasionou efeitos negativos nas variáveis de crescimento, demonstrando assim a tolerância moderada das plantas de girassol à salinidade em substrato arenoso.

The physiological and biochemical photosynthetic properties of Lycium ruthenicum Murr in response to salinity and drought

To estimate the salt tolerance and drought tolerance of Lycium ruthenicum Murr, we designed a pot experiment to measure the physiological and biochemical photosynthetic mechanisms of this species by establishing a range of NaCl concentrations (0, 50, 100, 200 and 400 mM) and degrees of drought stress (30%, 60%, 75% and 100% of field capacity). The results showed that the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), chlorophyll (Chl), carotenoids (Cars), maximal fluorescence (Fm), optimal quantum yield of photosystem II (PSII) (Fv/Fm), performance index (PIABS), activity of the water-splitting complex (Fv/Fo), actual photochemical efficiency of PSII (ΦPSII) and photochemical quenching (qP) were stimulated by moderate salinity (0–100 mM) and low water deficit (75–100%) and inhibited by high salinity (200–400 mM) and severe water deficit (30–60%). The changes in minimal fluorescence (Fo) and nonphotochemical quenching (qN) were opposite. Furthermore, the contents of malondialdehyde (MDA), proline, superoxide dismutase (SOD), and peroxidase (POD) significantly increased with increasing stress levels. In summary, salt and drought stress can separately enhance the photosynthetic capability to some extent because of increases in Gs and PSII activity. With an increase in stress, nonstomatal limitations, inhibition of electron transport and the activity of PSII can lead to reductions in photosynthetic capability. In addition, increases in osmotic substances and antioxidant enzymes can increase photosynthesis to some extent, but the physiological photosynthetic mechanisms are not protected from damage as these substances and enzymes continually increase. In summary, the resulting information can provide a theoretical basis and reference for construction of the ecological environment of the Qaidam area and the popularization and cultivation of Lycium ruthenicum Murr, thereby increasing ecological, social and economic benefits.

Humic substances: a valuable agronomic tool for improving crop adaptation to saline water irrigation

Abstract Availability of fresh water for crop irrigation is becoming scarce and rather expensive. In this context, the research about the potential reutilization of non-conventional water sources becomes highly relevant, principally in arid and semi-arid areas. On many occasions, these new water resources involve water with a moderate concentration of salt, making it necessary to improve plant growth under moderate saline conditions. Besides plant breeding techniques, the use of molecules able to improve plant adaptation to saline conditions has great interest. Between these molecules, humic substances (HS) have proven to be efficient as stress-protectors under specific conditions of stress intensity and moment of application. The HS are main components of the soil organic matter and dissolved organic matter resulting from the biotic and abiotic transformation of fresh organic matter in natural ecosystems. Although knowledge about their structure is still under open debate, HS contain aromatic and aliphatic domains presenting O-, N- and S- containing functional groups with high biological and chemical activities. The aim of this presentation is to summarize the main effects of humic acids (HA) applied either on the root or on the shoot, on the metabolism and hormonal balance of plants cultivated under normal and stressing conditions, from studies carried out for our group and collaborations during the last years. Summarizing, all these results show HA as a promising tool for improving crop adaptation to irrigation using moderate saline water sources.

Oxidative Stress and Histopathological Alternations in Sheep as A Result of Drinking Saline Water Under the Arid Conditions of Southern Sinai, Egypt

abstract Water is an essential nutrient so it is important for animals to have an adequate supply of good quality water to maintain satisfactory production. This experiment was carried out to study the effect of drinking varying degrees of natural saline well-water on oxidative stress and histopathological alternation of heart and lung indices of experimental sheep groups in the study area under the arid conditions of southern Sinai. Thirty Barki sheep were allocated into three groups based on the type of drinking water for nine months: the tap water (TW) group, the moderate saline water (MSW) group and the high saline water (HSW) group. Data revealed that, sheep which drinking well water (~5000ppm&~10000ppm) induced in serum samples significant increase of oxidative stress markers (malondialdehyde (MDA) and nitric oxide (NO)) & cortisol and decrease in the values of antioxidants parameters, superoxide dismutase (SOD), total glutathione (GSH), catalase (CAT) and total antioxidant capacity (TAC) compared to sheep drinking tap water. Histopathological examination of lung revealed catarrhal bronchitis and bronchiolitis, hyperplasia of epithelial lining and goblet cell with clear peri bronchial lymphocytic aggregates and edema. Fibrosis, haemorrhagic pneumonia, interstitial pneumonia and abscess formation. On the other hand, heart revealed significant changes in both MSW and HSW groups such as zenker necrosis of muscles, granulation of cytoplasm, slight hemorrhage moderate to severe edema and infiltration of inflammatory cells. In conclusion, water salinity negatively affects oxidative stress and heart & lung appearance of sheep.

Morpho-anatomical, physiological and biochemical adaptive responses to saline water of Bougainvillea spectabilis Willd. trained to different canopy shapes

Bougainvillea is widely used as potential ornamental shrub in revegetation and landscaping projects as well as in urban landscape design in Mediterranean areas characterized by saline and sodic soils. The current research aimed at elucidating the morphological, physiological and biochemical changes occurring in Bougainvillea spectabilis ‘Alexandra’ grown under salt stress conditions (1 mM [S1, electrical conductivity EC = 2.0 dS m−1] non-salt control, 40 mM [S40, EC = 6.5 dS m−1] and 80 mM [S80, EC = 11.0 dS m−1] NaCl). The response of plants trained to two canopy shapes (globe [GSh] and pyramid [PSh]) has been compared in order to unravel possible adaptive mechanisms, combining morpho-functional traits at different levels, to cope with saline water. PSh plants under moderate saline water (40 mM NaCl) showed higher leaf dry weight, leaf number and area as well as higher number of flowers per plant than those observed in GSh Bougainvillea plants. Saline water-triggered leaf anatomical changes were also harmonized to physiological adjustments in both canopy shapes in such a way to counteract the reduction in transpiration due to stomatal limitations by adopting traits improving CO2 diffusion in the mesophyll and investing more resources in the assimilatory tissue (e.g. increase in intercellular spaces and incidence of palisade parenchyma over the total mesophyll thickness). Bougainvillea plants enact many-sided strategies to acclimate to S80 salinity by harmonizing several mechanisms including sodium and chloride inclusion in leaves and their compartmentalization in vacuoles, retention of high levels of potassium in the cytosol to osmotically balance the cytoplasm and other organelles within the vacuole, modulation of leaf functional anatomical traits, in addition to a C2 Kranz mechanism of photosynthesis which allow plants to successfully cope with stress.

Impact of Low and Moderate Salinity Water on Plant Performance of Leafy Vegetables in a Recirculating NFT System

Two greenhouse experiments were conducted to examine the growth and mineral nutrition of four leafy vegetables in a nutrient film technique (NFT) system with water with low to moderate salinity. In Expt. 1, a nutrient solution was prepared using reverse osmosis (RO) water and treatments consisted of supplementing with RO water, tap water, or nutrient solution. In Expt. 2, nutrient solution was prepared using three different water sources (treatments), namely, RO water, tap water, or tap water, plus sodium chloride (NaCl), and supplementing solution was prepared using the same three water sources at one third strength. For both of the experiments, seeds of pac choi ‘Tokyo Bekana’, ‘Mei Qing Choi’, and ‘Rosie’ (Brassica rapa var. chinensis) and leaf lettuce ‘Tropicana’ (Lactuca sativa) were sown and were grown in a growth chamber. Two weeks after sowing, seedlings were transplanted to the NFT systems. Expt. 1 was conducted from 19 April to 19 May 2016 and Expt. 2 from 6 September to 12 October 2016. In Expt. 1, nitrate (NO3−) and phosphorus (P) levels in the tanks decreased, and potassium (K+) levels reached almost zero at the end of the experiment when supplemented with RO or tap water. However, calcium (Ca2+), magnesium (Mg2+), and sulfate (SO42−) either did not decrease or increased over time. Supplementing water type did not affect the growth of leaf lettuce and ‘Mei Qing Choi’ pac choi; however, fresh weight of ‘Rosie’ pac choi and both fresh and dry weight of ‘Tokyo Bekana’ pac choi were reduced when supplemented with RO water. Leaf sap NO3− was reduced in ‘Tokyo Bekana’ pac choi, but not in other varieties, when supplemented with RO or tap water. Leaf sap K+ decreased in ‘Tokyo Bekana’, but not in other varieties. The supplementing water type did not impact leaf sap Ca2+, regardless of vegetable varieties. In Expt. 2, NO3− in all of the treatments, P in RO water, and K+ in RO or tap water decreased in the last week of the experiment. Other macronutrients did not change substantially over time. The addition of NaCl significantly reduced the growth of all the vegetables. ‘Tropicana’ leaf lettuce was the least tolerant to NaCl, followed by ‘Rosie’ pac choi. Water source did not affect leaf Ca2+, K+, P, SO42−, and Mg2+ except for ‘Tokyo Bekana’ where NaCl addition decreased Ca2+ and Mg2+. Our results indicated that the tested leafy vegetables differed in response to various types of water used as supplementing or as source water. N, P, and especially K, should be supplemented in the late stage of the experiment, while replacing the whole tank nutrient solution is only necessary when Na+ and/Cl− build up to harmful levels.

Interactive Effects of Soil Salinity and Water Table Depth on Soil Properties and Sorghum (Sorghum Bicolor L. Moench) Production

Soil salinity and water table are the most prevalent and widespread problems limiting crop productivity in irrigated agriculture. Our experiment aims to evaluate the effect of soil salinity and water table on some soil properties, growth, and yield of sorghum (variety Giza 15) grown along two successive seasons. Nine different sites were chosen, representing three levels of soil salinity (i.e. ECe < 4, 4-8 and 8-16 dS m-1). For each salinity level three water table were selected (i.e. shallow ≈ 55 cm, medium ≈ 80 cm and deep ≈ 120 cm). Results revealed that there are main considerable effects of salinity and water table on some soil properties. Increasing of salinity caused significant decreases in plant growth, weight of 1000 grains (g), protein content% and seed yield (t/ha) which decreased by 36.98%, 32.27%, 20.45%, 29.95 % and 57.46% respectively, when salinity increased from S1 to S3. On the other hand, decreasing of water table lead to improvement in all mentioned soil properties and plant growth. The results indicated that need to maintain low or moderate salinity and deep water table, which is essential for producing high sorghum grain yield with satisfactory quality.

The effects of saline water consumption on the ultrasonographic and histopathological appearance of the kidney and liver in Barki sheep.

The objective of this study was to evaluate the impact of varying degrees of water salinity on the ultrasonographical and histopathological appearance of the liver and kidneys in Barki sheep. Thirty Barki sheep (initial weight, 29.48 ± 0.81 kg) were allocated into three groups (n=10 per group) based on the type of drinking water for 9 months: the tap water (TW) group (350 ppm total dissolved solids [TDS]); the moderate saline water (MSW) group (4,557 ppm TDS); and the high saline water (HSW) group (8,934 ppm TDS). After 9 months, the body weight was significantly decreased in sheep subjected to MSW (P=0.0347) and HSW (P=0.0424). Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, urea, and creatinine were significantly increased (P<0.05) in sheep subjected to MSW and HSW. Ultrasonographic examination of the right and left kidneys revealed an increased length of both kidneys with crystal formation, particularly in male sheep. Ultrasonographic examination of the liver showed hyperechogenic dots varying in size and number between males and females. Histopathological examination of kidney revealed significant changes in both MSW and HSW groups such as hyaline matrix formation, atrophied glomerular tufts, and intramedullary congestion. Histopathological examination of the liver revealed slight fatty liver changes, slight fibrosis around the bile duct, massive inflammatory cell infiltration and vacuolar changes of hepatocytes in both MSW and HSW groups. In conclusion, water salinity negatively affects the body weight, liver and kidney appearance of Barki sheep and thus sheep production.

Studying of the combined salts effect on the engineering properties of clayey soil

In recent years, a number of studies had been performed to investigate the effect of pore water chemistry on the strength and compressibility characteristics of soil. Although the effect of chloride and sulfates salts separately in pore fluids on the geotechnical properties of soil seems to be well understood, but the influence of combined effect of sulfates and chlorides in pore water on the behavior of soil is still unclear mostly due to the limited numbers of studies as well as the complexity of processes that may occur in soil (with the presence of salts) in pore water-soil interaction. Southern regions of Iraq, especially Basra suffers from low water levels in the summer season in addition to the lack of rain water, which causes a significant increase of salt in the Shatt al Arab. Water salinity continues to increase with time. To investigate the combined impacts of water salinity on the behavior of clayey soils, the basic characteristics of the soil brought from Al-Nahrawan site was studied. Chemical methods were done with three types of water (distilled, water of highly saline as Shatt Al-Arab water and water of Tarmiya as moderate saline water). The effect of water salinity on the geotechnical properties of fine grain soil was investigated. Different laboratory tests such as Atterberg limits, standard compaction, consolidation and shear strength of soil .Results showed that the presence of perceptible amounts of dissolved salts in water can lead to changes in the engineering properties of the soil.

Erratum to: Mitigation of Salt Stress Negative Effects on Sweet Pepper Using Arbuscular Mycorrhizal Fungi (AMF), Bacillus megaterium and Brassinosteroids (BRs)

A study was conducted at the experimental farm of Faculty of Agriculture, Ain Shams University, Cairo, Egypt, during two successive summer seasons (2014 and 2015) to investigate the effects of arbuscular mycorrhizal fungi (Glomus irradicans 10% w/w), Bacillus megaterium (10 ml/pot) and brassinosteroids (24-EBL, C28H48O6; 2 µM) on growth, nutrient absorption, chlorophyll, proline content, antioxidant enzymes activity and fruit yield of sweet pepper plants (Capsicum annuum L.) cv. Marconi. Plants were grown under three levels of salinity (0, 25 and 50 mM). The obtained results showed that plants grown under non-saline water (0 mM NaCl), with or without treatments, significantly gave the most vigorous vegetative growth and had the highest fruit yield compared with those grown under salt stress conditions. All anti-salinity treatments (Mycorrhiza, Bacillus and Brassinosteroids) improved growth when compared with untreated plants (control). Plants inoculated with mycorrhiza or treated with brassinosteroids showed better vegetative growth and shoot biomass (total fresh and dry weight per plant), chlorophyll a and b concentrations, antioxidant content expressed as total soluble phenols and proline concentrations at all studied salinity levels followed by plants inoculated with Bacillus megaterium compared with control plants which showed severe growth retardant especially under higher salt concentration (50 mM). Carotenoids concentration increased proportionally with the increase of salinity concentration. The maximum leaf relative water content (LRWC) and lowest values of membrane permeability (MP) were significantly observed with mychorhiza inoculated plants and brassinosteroid application respectively, followed by Bacillus inoculated plants. Antioxidant enzyme activity were highest in plants irrigated with moderate saline water (25 mM) than plants under high salinity irrigation water (50 mM) except polyphenol oxidase (PPO) as compared with unstressed plants (0 mM). Mycorrhizal inoculated plants accumulated higher K and lower Na and Cl followed by plants treated with brassinosteroids and then plants inoculated with Bacillus megaterium. Anti-salinity treatments positively enhanced fruit yield of sweet pepper plants under all salinity stress levels and the highest fruit yield were significantly observed with brassinosteroid application followed by mychorhiza inoculated plants and then Bacillus inoculated plants.

Biotechnological potential of Kuantan mangrove actinomycete, Micromonospora K3-13

Introduction: Mangrove is a complex and unique ecosystem which experiences periodical tidal flooding inundated with low, moderate and high salinity water. Its muddy soil is rich in organic matter derived from the efficient nutrient cycling system and decomposition of mangrove leaves. An adaptation of mangrove microorganisms towards these environmental factors could promote the production of interesting bioactive compounds and enzymes. Methods: This study determines to unravel the identity and biotechnological potential of a Kuantan mangrove actinomycete, strain K3-13, through morphology observation, molecular identification, antimicrobial test and xylan degradation test. Results: The orange-colored mycelium-forming isolates produced spores after a long incubation period, and showed characteristics that resembled Micromonaspora colonies. Phylogenetic analysis of the 16S rRNA gene sequence of strain K3-13 indicated that the highest similarity was to Micromonospora carbonacea DSM43168 (99%). It was observed that K3-13 produced blue diffusible pigment upon cultivation on agar media. Cross streak assay conducted to detect antimicrobial activity indicated that K1-13 has strong antibacterial activity against Bacillus subtilis and Staphylococcus aureus. K3-13 also showed positive xylanase activity by exhibiting decolourization zone in the agar-based assay using azo-xylan as substrate. Conclusions: On the basis of its ability to produce blue pigment, antimicrobial activity against at least two test organisms and positive xylan degrading activity, Micromonaspora K3-13 is concluded as strain worth exploring for its potential biotechnological application as a natural dye, antibacterial drugs and Xylan biodegraders.

Does selection in a challenging environment produce Nile tilapia genotypes that can thrive in a range of production systems?

This study assessed whether selection for high growth in a challenging environment of medium salinity produces tilapia genotypes that perform well across different production environments. We estimated the genetic correlations between trait expressions in saline and freshwater using a strain of Nile tilapia selected for fast growth under salinity water of 15–20 ppt. We also estimated the heritability and genetic correlations for new traits of commercial importance (sexual maturity, feed conversion ratio, deformity and gill condition) in a full pedigree comprising 36,145 fish. The genetic correlations for the novel characters between the two environments were 0.78–0.99, suggesting that the effect of genotype by environment interaction was not biologically important. Across the environments, the heritability for body weight was moderate to high (0.32–0.62), indicating that this population will continue responding to future selection. The estimates of heritability for sexual maturity and survival were low but significant. The additive genetic components also exist for FCR, gill condition and deformity. Genetic correlations of harvest body weight with sexual maturity were positive and those between harvest body weight with FCR were negative. Our results indicate that the genetic line selected under a moderate saline water environment can be cultured successfully in freshwater systems.

Changes in volatile compounds and oil quality with the method of olive tree propagation and saline water irrigation

The main goal of this study was to investigate the effects of moderate saline water irrigation on the composition and quality of olive oil of the “Chemlali” olive cultivar in comparison to a control plot grown under rain-fed conditions from two methods of olive tree propagation (suckers and cuttings). The antioxidant compounds, oxidative stability and volatile compounds of virgin olive oil samples were determined and reported. The irrigation did not affect free acidity and peroxide value and specific ultraviolet absorbance (K232, K270). Whereas, fatty acid composition, oxidative stability, total phenol, total chlorophyll and carotenoid contents were affected by irrigation. Rain-fed virgin olive oils showed a statistically significant higher content of oleic and linoleic acids. However, olive oil samples obtained from fruit of irrigated trees from suckers had a higher content of (E)-2 hexenal (67.2%) and a higher content of total phenols (860 mg kg–1). Interestingly, more stable oil was obtained from moder...

Groundwater salinity and hydrochemical processes in the volcano-sedimentary aquifer of La Aldea, Gran Canaria, Canary Islands, Spain

The origin of the groundwater salinity and hydrochemical conditions of a 44km2 volcano-sedimentary aquifer in the semi-arid to arid La Aldea Valley (western Gran Canaria, Spain) has been studied, using major physical and chemical components. Current aquifer recharge is mainly the result of irrigation return flows and secondarily that of rainfall infiltration. Graphical, multivariate statistical and modeling tools have been applied in order to improve the hydrogeological conceptual model and identify the natural and anthropogenic factors controlling groundwater salinity. Groundwater ranges from Na–Cl–HCO3 type for moderate salinity water to Na–Mg–Cl–SO4 type for high salinity water. This is mainly the result of atmospheric airborne salt deposition; silicate weathering, and recharge incorporating irrigation return flows. High evapotranspiration produces significant evapo-concentration leading to relative high groundwater salinity in the area. Under average conditions, about 70% of the water used for intensive agricultural exploitation in the valley comes from three low salinity water runoff storage reservoirs upstream, out of the area, while the remaining 30% derives from groundwater. The main alluvial aquifer behaves as a short turnover time reservoir that adds to the surface waters to complement irrigation water supply in dry periods, when it reaches 70% of irrigation water requirements. The high seasonality and intra-annual variability of water demand for irrigation press on decision making on aquifer use by a large number of aquifer users acting on their own.

The Role of Humic Acid and Proline on Growth, Chemical Constituents and Yield Quantity and Quality of Three Flax Cultivars Grown under Saline Soil Conditions

In order to mitigate the salinity effects on flax grown on moderate saline sandy soil (3275 - 3430 ppm) and irrigated with moderate saline water (2300 - 2460 ppm) field experiments were carried out at the experimental Station of the Faculty of Agriculture, Wadi El-Natrun district El-Behera Governorate—Egypt, during two successive winter seasons of 2012/2013 and 2013/2014. Three flax varieties (Opal, Giza-8 and Mayic) were grown and treated with some chemical additives humic acid (50 kg/fed) and/or foliar applied proline (Control, 50 and 100 mg/L). The results showed the positive responses of Giza-8 variety to the combined application of humic acid and proline and mitigated the salinity effects of soil and irrigation water and reflected on most of the studied characters. Such results indicate the potentiality of mitigation the hazardous effect of salinity with these chemical additives. The data indicated that the highest seed yield, straw yield and oil yield were obtained at humic acid (50 kg/fed) with foliar treatment of proline at rate of (100 mg/L). The interaction of proline at (100 mg/L) with humic acid at rate of (50 kg/fed) improved plant fresh and dry weight in all flax cultivars under salinity conditions. Fresh weight increased by 66.6%, 48.7% and 65.5% over controls for Opal, Giza-8 and Mayic varieties, respectively. The interaction of proline at (100 mg/L) with humic acid at rate of (50 kg/fed) with Giza-8 variety gave the highest values of seed yield, straw yield and oil yield.

Hydrogeochemical assessment of groundwater quality along the coastal aquifers of southern Tamil Nadu, India

Hydrogeochemical investigation of groundwater has been carried out in the coastal aquifers of southern Tamil Nadu, India. Seventy-nine dug well samples were collected and analyzed for various physicochemical parameters. The result of the geochemical analysis indicates the groundwater in the study area is slightly alkaline with moderate saline water. The cation and anion concentrations confirm most of the groundwater samples belong to the order of Na+ > Mg2+ > Ca2+ > K+ and Cl− > SO4 2− > HCO3 −. Thereby three major hydrochemical facies (Ca–Cl, mixed Ca–Mg–Cl and Na–Cl) were identified. Based on the US Salinity diagram, majority of the samples fall under medium to very high salinity with low to high sodium hazard. The cross plot of Ca2+ + Mg2+ versus chloride shows 61 % of the samples fall under saline water category. Higher EC, TDS and Cl concentrations were observed from Tiruchendur to Koodankulam coastal zone. It indicates that these regions are significantly affected by saltwater contamination due to seawater intrusion, saltpan deposits, and beach placer mining activities.

Evaluating salinity distribution in soil irrigated with saline water in arid regions of northwest China

In arid and semi-arid regions, salinity is a serious and chronic problem for agriculture. A 3-year field experiment in the arid environment of Xinjiang, northwest China, was conducted to study the salinity change in soil resulting from deficit irrigation of cotton with non-saline, moderate saline and high saline water. The salinity profile distribution was also evaluated by an integrated water, salinity, and nitrogen model, ENVIRO-GRO. The simulated and observed salinity distributions matched well. Results indicated that after 3 years of cotton production, the average salinity in the 1.0-m soil profile was 336% and 547% of the original soil profile, respectively, for moderate saline and high saline water irrigation. If the practices continued, the average soil salinity (ECe) in the 1.0-m soil profile would approach a steady level of 1.7, 10.8, and 14.7 dS m−1, respectively, for the treatments receiving irrigation waters of 0.33, 3.62, and 6.71 dS m−1. It was concluded that deficit irrigation of saline water in this region was not sustainable. Model simulation showed that a big flood irrigation after harvest can significantly reduce the salt accumulation in the soil profile, and that this practice was much more efficient for salinity control than applying the same extra amount of water during the growing season.

Holocene paleolimnological changes in Lake Skallen Oike in the Syowa Station area of Antarctica inferred from organic components in a sediment core (Sk4C-02)

Antarctic climate changes influence environmental changes at both regional and local scales. Here we report Holocene paleolimnological changes in lake sediment core Sk4C-02 (length 378.0 cm) from Lake Skallen Oike in the Soya Kaigan region of East Antarctica inferred from analyses of sedimentary facies, a range of organic components, isotope ratios of organic carbon and nitrogen, and carbon-14 dating by Tandetron accelerator mass spectrometry. The sediment core was composed of clayish mud (378.0–152.5 cm) overlain by organic sediments (152.5 cm-surface). The age of the surface and the core bottom were 150 (AD1950-1640) and ca. 7,030 ± 73 calibrated years before present (cal BP), respectively, and the mean sedimentation rate was estimated to be 0.55 mm/year. Multi-proxy analyses revealed that the principal environmental change in the core is a transition from marine to lacustrine environments which occurred at a depth of 152.5 cm (ca. 3,590 cal BP). This was caused by relative sea level change brought about by ongoing retreat of glaciers during the mid-Holocene warming of Antarctica, and ongoing isostatic uplift which outpaced changes in global (eustatic) sea level. The mean isostatic uplift rate was calculated to be 2.8 mm/year. The coastal marine period (378.0–152.5 cm, ca. 7,030–3,590 cal BP) was characterized by low biological production with the predominance of diatoms. During the transition period from marine to freshwater conditions (152.5-approximately 135 cm, ca. 3,590–3,290 cal BP) the lake was stratified with marine water overlain by freshwater, with a chemocline and an anoxic (sulfidic) layer in the bottom of the photic zone. Green sulfur bacteria and Cryptophyta were the major photosynthetic organisms. The Cryptophyta appeared to be tolerant of the moderate salinity and stratified water conditions. The lacustrine period (approximately 135 cm-surface, ca. 3,290 cal BP-present) was characterized by high biological production by green algae (e.g. Comarium clepsydra and Oedegonium spp.) with some contributions from cyanobacteria and diatoms. Biological production during this period was 8.7 times higher than during the coastal marine period.

INFLUENCE OF IRRIGATION WITH MODERATE SALINE WATER ON “CHEMLALI” EXTRA VIRGIN OLIVE OIL COMPOSITION AND QUALITY

ABSTRACT The main goal of this study was to investigate the effects of moderate saline water irrigation in the “Chemlali” olive cultivar grown in Sfax, an arid region of Tunisia, on the composition and quality of the resultant virgin olive oil in comparison to a control plot grown under rain‐fed conditions. Free acidity, peroxide value, specific ultraviolet absorbance (K232, K270), fatty acid composition, induction time, total polyphenol and total chlorophyll contents were determined and reported. The irrigation did not affect free acidity and peroxide value. Whereas, specific ultraviolet absorbance (K232, K270), fatty acid composition, induction time, total polyphenol and total chlorophyll contents were affected by irrigation. Rain‐fed virgin olive oils showed a statistically significant higher content of oleic and linoleic acids. Virgin olive oils extracted from moderate saline water irrigated trees had higher contents of palmitic, palmitoleic, stearic and linolenic acids and a longer shelf‐life. A positive correlation was noted between polyphenol content and oxidative stability. PRACTICAL APPLICATIONSOlive trees are quite widespread in the south of Tunisia. They grow in semi‐arid environments. It is a species with high resistance to drought. However, irrigation allows productivity to increase in olive growing areas where rainfall is scarce. Irrigation is a determinant parameter for olive oil quality. In fact, high olive oil quality can not be obtained from olive fruit suffering from a high degree of water stress. The main purposes of this paper are to investigate the effects of moderate saline water on the commercial quality, the fatty acid composition, and the induction time, total polyphenol and total chlorophyll contents of “Chemlali” virgin olive oil in Tunisia.

Reproductive Compensation of Cotton after Salt Stress Relief at Different Growth Stages

AbstractDifferential salt sensitivity during growth stages and reproductive compensation of plants after salt stress relief are important factors for adopting appropriate irrigation strategies with saline waters. Consequently, recovery of cotton after exposure to different levels of salt stress was evaluated. An outdoor, sand culture experiment was conducted with cotton. Water salinities were 2, 10 and 20 dS m−1, and the growth phases were vegetative (G1), reproductive (G2) and boll development (G3). G1 and G3 were the least and the most salt tolerant phases, respectively. The significant yield reduction in all of the saline water treatments as compared to control was mainly due to the reduction in number of bolls per plants. In general, cotton plants were capable of producing seed cotton under salt stress, as well as, after salt stress relief. However, as the salt stress severity increased the ability of cotton to compensate yield loss decreased. Irrigation of cotton at G1 stage with either moderate (10 dS m−1) or high (20 dS m−1) salinity waters should be avoided. Moderate saline water could be applied either at G2 or G3 stage. High salinity water can be used for irrigation only at G3 stage to produce acceptable cotton seed yield.