Showing papers on "Saline water published in 1994"

The effect of microorganisms, salinity and turbidity on hydraulic conductivity of irrigation channel soil

Abstract: The introduction of polysaccharide producing benthic algae and bacteria could provide a low cost technique for seepage control in irrigation channels. The ability of algae and bacteria to produce polysaccharides proved to be successful in reducing the hydraulic conductivity of irrigation channel soil. Hydraulic conductivity was reduced to less than 22% of its original value within a month of inoculating soil columns with algae. Chlorophyll and polysaccharide concentrations in irrigation channel soil were measured in order to assess the growth of algae and extent of polysaccharide production, and their correlation with hydraulic conductivity of channel soil. Increases in polysaccharide occurred in the top layer (0–5 mm) of the soil column. The reduction of hydraulic conductivity was highly correlated with the amount of polysaccharides produced (r 2 = 0.92). Hydraulic conductivity decreased with increasing algal and bacterial numbers. The first few millimetres of the soil core where microbial activity was concentrated, seemed effective in controlling seepage. Incorporation of extra nitrate and phosphate into algal medium did not increase the production of polysaccharides by algae in channel soil. The effect of salinity and turbidity of irrigation channel water on channel seepage was studied by measuring the effects on hydraulic conductivity of channel soils. When the electrical conductivity (EC) of the water increased above a threshold value, the hydraulic conductivity increased because of the flocculating effects on clay particles in channel soils. A relationship between sodium adsorption ratio (SAR) and EC of the channel water was established which indicated 15% increase in channel seepage due to increases in salinity. Increasing the turbidity of irrigation water (by increasing the concentration of dispersed clay) resulted in lowering the hydraulic conductivity of the channel soil due to the sealing of soil pores by dispersed clay particles. When the turbidity of the water was 10 g clay l−1, the hydraulic conductivity was reduced by 100%. An increase in clay concentration above 1 g l−1 resulted in significant reduction in hydraulic conductivity. Soil bowl experiments indicated that clay sealing with a coating of hydrophobic polymer on the surface could also effectively prevent seepage of saline water.

Salinity induced changes in vegetative and reproductive growth in tomato

Abstract: Vegetative and reproductive growth were studied in five tomato (Lycopersicon esculentum Mill) cultivars under saline conditions imposed at the five‐leaf stage by addition of 50 mM NaCl to half strength Hoagland nutrient solution. The plants were raised in pots filled with washed quartz sand kept in a greenhouse. Stem height and number of leaves in tomato plants were significantly reduced when irrigated with saline regimes in contrast with control plants that received only the Hoagland solution. The highest number of flowers were obtained in the cultivar Pearson and the least in cultivar Strain B. Fruit set and yield were little affected by varietal differences and were not related to vegetative growth. Fruit weight was suppressed with NaCl stress, but improvement in weight was achieved when potassium (K) and calcium (Ca) were added to the saline water. The most detrimental effect of NaCl stress was the reduction of biomass yield in tomatoes. However, the relative dry weights of Pearson and Monte ...

Growth, yield and water relations of normal fruited and cherry tomato cultivars irrigated with saline water

Abstract: SummaryPlants of a tomato cultivar of normal fruit-size, weak vegetative development and high productivity (L. esculentum cv. New Yorker) and another of small fruit-size (cherry) and strong vegetative development (L. esculentum var. cerasiforme cv. PE-62) were grown in an unheated plastic greenhouse and irrigated with 0 and 140 mM NaCl water (control and saline treatments, respectively). The shoot and leaf dry weights and leaf area reductions induced by salinity were related to the osmotic adjustment achieved at each time and cultivar. Plants of cv. PE-62 showed a decrease in shoot to root dry-weight ratio in response to salinity. Yields of both cultivars were reduced significantly by salinity; a result of a fewer fruits and smaller fruits. Fruits from salt treated plants contained a higher concentration of reducing sugars and organic acids than those of control plants. The fruit life span was shortened in plants under saline stress. In both cultivars, the leaf osmotic potential at full turgor (Ψos) level...

Utilization of halophytic plants for fodder production with brackish water in subtropic deserts

Abstract: The arid and semi-arid regions of the subtropic zone in the Northern Hemisphere are in most parts faced with frightening rates of population growth, overgrazing, and land degradation. Among the major natural resources of arid and semi-arid deserts, brackish water (containing dissolved salts of 5 to 20 g L-1) is currently the least explored resource, primarily because the salinity is too high to produce conve rational crops. Irrigated production of halophytic plants (which include halophytes and salt tolerant nonha lophytes) offers potential for utilization of brackish water to supplement fodder needs. However, the knowledge required to evaluate and manage irrigated production with brackish waters has not been adequately developed. In this chapter, we examined saline tolerance characteristics of halophytic plants, ways to characterize water and soils for irrigated production, and various potential system options for irrigated production. Although there are exceptions, salt tolerance of most halophytic plants at germination does not appear to be any higher than that of conventional crops, thus requiring careful management or establishment. Many halophytic plants show optimum growth at soil solution salinity of 20 to 25 g L-1and 25 to 50% growth reductions at 30 to 40 g L-1even though they can survive soil solution salinity as high as 60 to 90 g L1. Forage yields and quality of some halophytic plants are comparable to conventional forage crops. However, excessive uptake of salts and, in some instances, toxic substances such as Se and Mo may reduce fodder values unless blended with conventional fodder. Under ordinary leaching fractions employed (less than 0.25), irrigated production of halophytic fodder plants appears to be optimum at irrigation water salinity of less than 10 g L-1 (13 to 15 dS m-1), and would be reduced substantially when salinity of irrigation water approaches 20 g L-1. Salinity of drainage water can easily reach the seawater level salinity (35 g L-1) or even higher. The quantity of salts that must be leached for sustainable production is in an order of 100 tons per ha annually. Halophytic plants can be raised in conventional monoculture systems using sprinklers or surface irrigation, especially when salinity of water is too high for conventional crops (typically above 5 g L-1). Multicrop culture using strip planting of halophytic crops between conventional forage crops or irrigated silvipasture systems could also be used to an advantage, especially for reducing drainage water handling. Halophytic plants grown in strips with limited irrigation can utilize saline water from the shallow water table, and can remove dissolved salts at a rate of 5 to 10 Mg ha-1 annually. The possibility of biofiltration of toxic trace elements from drainage water warrants extensive studies. Future prospects for halophytic fodder production seem to depen i to a large extent upon the success of ongoing selection programs, enhanced breeding efforts, a considerable amount of agrotechnical evaluation, including the aspects of biofiltration and production systems, and improved understanding of the role of halophytes in saline water and soil management.

Irrigation with Saline Water

Abstract: Crop production in arid and semi-arid regions of the world is dependent upon an adequate supply of suitable-quality water. A supply of water is considered adequate when sufficient quantities are readily available for irrigation throughout the season to meet crop-water needs. This depends not only on the absolute quantity of water available, but on the scale of irrigated agriculture imposed on a region. In areas where irrigated agriculture frequently encounters irrigation water shortages, emphasis is usually placed on methods of increasing water quantity (e.g., utilizing groundwater; Howitt and M’Marete 1991), rather than considering whether water demands placed on such arid regions have been too high to ensure a dependable long-term supply. In some extremely arid countries, however, development of new irrigation water supplies is necessary to maintain a stable food supply. In order to expand its water resource base, the country or region must be able to utilize poorer quality water. The quality of water is considered suitable for crop production providing it can be used alone or in conjunction with other water sources and can sustain economic yields over the long term. The actual quality of water that is suitable for irrigation, as outlined in Chapter 2, depends upon crop salt tolerance, site conditions, and management practices.

Method and apparatus for the desalination of salt containing water

Abstract: A method and kit for chemically rendering saline water safe to drink is disclosed. The kit includes a chemical reactant which on contact with the saline water is operable to bond with free sodium and chloride ions in the water and exchange therefore, carbonate, bicarbonate and hydrogen ions. The substituted carbonate, bicarbonate and hydrogen ions combining to form biologically safe water and carbon dioxide molecules.

Effect of amendments and saline irrigation water on soil properties and yields of rice and wheat in a highly sodic soil

Abstract: A field experiment at Gudha Experimental Farm, Central Soil Salinity Research Institute, Karnal, India, in 1983/84 evaluated the effect of gypsum (12·5 t/ha, 50% of gypsum requirement of soil), pyrite (10·2 t/ha, equivalent to gypsum on a sulphur basis), farmyard manure (FYM) (30 t/ha), gypsum + FYM, pyrite + FYM and a control, with saline (ECiW 4·0 dS/m) and non-saline (0·4 dS/m) irrigation water on soil properties and yields of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) in a highly sodic soil (pH 10·5, 96% exchangeable sodium). Application of these amendments enhanced the yield of both crops significantly, irrespective of the quality of the irrigation water used. Soil properties and crop yields were improved in the following order: control < FYM < pyrite < gypsum < pyrite + FYM < gypsum + FYM. Irrigation with saline water resulted in significantly higher yields of both crops than irrigation with non-saline water. Decreases in soil pH and exchangeable sodium and increases in exchangeable Ca + Mg and infiltration rate were greater after rice than wheat in the rotation, particularly when non-saline water was used.

Chloride accumulation and partitioning in Barley as affected by differential root and foliar salt absorption under saline sprinkler irrigation

Abstract: Barley is a crop that has been classified as tolerant to soil salinity, but under sprinkler irrigation with saline water it can readily absorb salts through its leaves and develop injury. Experiments using a triple-line-source sprinkler system were conducted on barley between 1989 and 1991 to determine: (1) the specific effects of foliage wetting on the mass of different shoot components; (2) the relative contribution of root and foliar absorption processes to foliar Cl accumulation; and (3) the extent by which these processes affect Cl partitioning in the shoot at the end of the season. Some plants were covered with plastic during the irrigation process to prevent foliar wetting while others remained uncovered. Salinity affected the partitioning of dry matter in the shoots regardless of whether plants were covered during the irrigation process. The organs associated with reproduction, e.g., heads and peduncles, comprised a larger fraction of the total shoot biomass under high salinity than under low salinity, indicating that plants under salinity stress were able to redistribute their dry matter to favor reproductive growth. The Cl concentration of the young leaves sampled from uncovered plants was linearly related (i.e., r2>0.71) to the Cl concentration of the irrigation water. Equivalent leaves from covered plants also contained a substantial amount of Cl but concentrations were weakly correlated (i.e., r2<-0.41) with the concentration of Cl in the irrigation water. At low salinity, there were no differences in leaf Cl concentrations between covered and uncovered treatments. In young leaves, differences between these treatments progressively increased with increasing salinity, indicating that the relative contribution of Cl in the leaf from foliar absorbed salts increased with increasing Cl in the irrigation water. Only in the youngest leaves sampled at the end of the season from plants grown at high salinity was the Cl concentration in uncovered plants (foliar plus root-absorbed Cl) found to be more than twice that in covered plants (only root-absorbed Cl) indicating that most of the Cl in young leaves originated from foliar absorption. In addition, only in the youngest leaves (e.g., flag leaves) was the slope of the relationship between leaf-Cl concentration and Cl concentration of the sprinkling water of uncovered plants more than twice that of covered plants, also indicating that foliar-Cl absorption was more substantial than root-Cl absorption. At high salinity, the difference in leaf Cl concentration between covered and uncovered plants was maximum in the youngest leaf (flag leaf), but differences became progressively smaller with increasing leaf age until ultimately concentrations of chloride in leaves older than the flag leaf-2 were highest in covered plants. In older tissue, it was difficult to distinguish which process, foliar or root absorption, was most responsible for leaf-Cl accumulation. These processes may not be entirely independent of one another and much of the Cl in the oldest leaves of uncovered plants could have been derived from foliar sources during the first month of sprinkling, reaching maximal levels, and thereby restricting root-absorbed Cl. Furthermore, since these leaves at the end of the season are more injured and drier than those from covered plants, late-season sprinkler irrigations may have been responsible for leaching some of the Cl out of these necrotic leaves.

Precipitation and separation of salts, scale salts, and norm contaminant salts from saline waters and saline solutions

Abstract: In this invention, a novel process for saline waters and saline solutions conversion has been provided that requires only a fair amount of a miscible organic solvent and heat transfer. Such requirements are ordinary in the nature of precipitation and vaporization. The invented process consists of adding a miscible (strongly associated) organic solvent to saline water so that salt precipitates of the saline water is formed. The resultant salt precipitates (pure solids) is then separated from the organic-water mixture. After separating the salt precipitates, the miscible organic solvent is removed and recovered from the organic-water mixture by applying vacuum with or without heating, or by using distillation methods. The separated miscible organic solvent can then be condensed and returned to the process and water is stripped of trace of miscible organic solvent, and removed from the system as product water. The invented process is potentially suited for the precipitation and separation of salts, scale salts, and NORM contaminant salts form saline water and saline solution as well as for the remediation of contaminated soils.

Spectral reflectance characteristics of salt-affected arid soils of Rajasthan

Abstract: The spectral reflectance characteristics of different types of natural and anthropogenic salt-affected soils have been studied under field conditions. The spectral reflectance value for non-saline and all types of salt-affected soils was maximum in near infra red region (800–1000 nm). The natural salt-affected soils having surface salt encrustation showed highest reflectance value followed by the sodic soils (formed due to high residual sodium carbonate water irrigation) natural saline soils and saline soils due to saline water irrigation. Soil texture, pH, CaC03 and organic matter together accounted for 29.6% variation in the maximum reflectance percentage value out of which only pH accounted for more than half (14.2% variation).

Leaf, stolon and root growth of white clover (Trifolium repens L.) in response to irrigation with saline water

Abstract: The effect of irrigation with water at salinity concentrations of 2.6 and 5.2 dS m−1 on the growth of pure swards of six cultivars of white clover (Trifolium repens L.) was examined over three irrigation seasons at Tatura, Victoria, Australia. After two irrigation seasons, soil EC e levels increased to 6 dS m−1 at 0–60 cm depth in the higher salinity treatment resulting in highly significant (p < 0.001) reductions in shoot dry matter production, flowering densities and petiole and stolon densities. These saline conditions also increased (p <0.001) concentrations of Cl and Na in the shoots and reduced (p < 0.001) leaf water potentials and canopy photosynthetic efficiency rates especially at high temperatures. In contrast, root growth increased at shallow depths (0–15 cm) under both saline irrigation treatments (p <0.001). Cultivars differed significantly in salt tolerance (p < 0.001), with cultivars Haifa and Irrigation exhibiting superior tolerance in terms of lower reductions in herbage yield (p <0.05) and petiole densities (p <0.001) during one irrigation season and lower concentrations of Na and Cl in the shoots (p <0.05) compared with the other four cultivars (Aran, Kopu, Pitau and Tamar). In addition, canopy photosynthetic efficiency rates (A *) in plots irrigated with water at 5.2 dS m−1 were higher in cultivar Haifa compared with cultivar Tamar (p <0.05). The salt tolerance ranking obtained for the six cultivars was in broad agreement with earlier greenhouse studies. Consequently, it appears that, while white clover is an extremely salt-sensitive species, it is possible to grow cultivars which display greater salt tolerance than other cultivars and which provide some scope to increase, or at least to maintain, pasture yields in areas where the soil salinity is low to moderate or where pumped saline groundwater is re-used for Irrigation.

A new and novel process for separation of salts, scale salts and norm contaminant salts from saline waters and saline solutions

Abstract: A new and novel process for saline waters and saline solutions conversion has been provided that requires only a fair amount of a miscible organic solvent and heat transfer. Such requirements are ordinary in the nature of precipitation and vaporization. The proposed process consists of adding a miscible (strongly associated) organic solvent to saline water so that salt precipitates of the saline water are formed. The resultant salt precipitates (pure solids) are then separated from the organic‐water mixture. After separating the salt precipitates, the miscible organic solvent is removed and recovered from the organic‐water mixture. The recovered miscible organic solvent can then be returned to the process, and water is stripped out of trace of miscible organic solvent, and removed from the system as product water. The proposed process is potentially suited for the precipitation and separation of salts, scale salts, and NORM contaminant salts form saline water and saline solution as well as for th...

Water problems in the Jaffna Peninsula

Abstract: agricultural activity related to short term crops. Water for drinking and for agriculture is obtained from open wells. Even the municipal area in Jaffna is supplied with water pumped from wells located in Kondavil, about three miles from Jaffna Town. Open wells are commonly built in villages, one for each household albeit with some of them shared by three or four neighbouring households who occupants are usually related to one and another. A recent innovation is the sinking of tube-wells to obtain water supply for drinking and irrigation to agricultural lands. Quality of water and affordable water supply In the early days, well sweeps or a system of pulleys were used to extract the water from the open wells, both for consumption as drinking water and for irrigation to crops. The fresh water in the aquifers floats in lens formation or varying thickness on saline water found below and has salinity levels depending on its location and distance from the sea. For example, a study on the geomorphology of the Valukkai Aru drainage basin in the Valigamam area showed that the salinity of the ground water in a location is inversely related to its distance from the sea. (Puvaneswaran, 1987). The amount of calcium, magnesium bicarbonates and sulphates present in the water contributed to its hardness which varied from moderately hard to hard in terms of calcium carbonate equivalent. Since the rate of extraction of the underground water was relatively slow, the recharge of the wells from the underground reservoir helped to maintain an affordable water supply of satisfactory quality in terms of salinity and hardness. Ground water recharge has been viewed as a function of effective rainfall. In the Jaffna Peninsula, this occurs only during the annual monsoon rainfall during the period September to January. After losses by direct runoff (about 10-15 per cent), and losses by evaporation (about 40-48 per cent), only 30 to 32 per cent of the rainfall is left over for ground water recharge. In the last three decades, the quality of water in the region has deteriorated due to various reasons. Variability of the rainfall over the region has indirectly contributed to this as rainfall over the region has indirectly contributed to this as rainfall is the only source of recharge. A sample of rainfall records for the period 1985-1993 given in Table 1 supports the variability of seasonal rainfall. The salinity problem was perceived as a hazard as early as the 1950's and 1960's and this has been

Corrosion Inhibition of Steel by Triazolidines in Saline Water

Abstract: As seawater is a complex, delicately balanced solution of many salts containing living matter, suspended silt, dissolved gases and decaying organic material, it is important to separate the effect of salts from the other factors to emphasize the corrosion rate due to the salinity. Salinity is defined as the total weight in grams of solid matter dissolved in 1,000g of water. The relative proportion of salts does not vary appreciably in interconnected seas. Variations in salinity in open‐ocean surface water typically range from 32–37.5 per cent. In open circulating systems, sea water may be used as industrial cooling waters, particularly for industry located at the coast. New technologies using non‐toxic organic instead of inorganic chemicals as corrosion inhibitors are advanced and have been introduced successfully in cooling waters treatment.

Desalination of water with zeolite(s)

Abstract: Desalination of saline water, esp. sea water, is effected by contacting a predetermined amt. of zeolites having the same or different lattice or mol. sieve structure with the water, removing the zeolites from the water, dehydrating the zeolites to release desalinated water, and collecting the desalinated water. Also claimed is the use of zeolites to desalinate saline water. Dehydration is pref. effected by evacuation or heating. The exothermic heat generated during contact of the zeolites with the saline water is utilised in the dehydration step.