Showing papers on "Saline water published in 1980"

The role of organic solutes in osmoregulation in halophytic higher plants.

Abstract: Excessive salt accumulations prevent or limit the growth of crops on at least 50 million hectares of agricultural land, particularly in areas where arid or semi-arid conditions exist (Carter, 1975). If these lands are to be used to increase plant productivity it is pertinent to examine the characteristics of plants which have evolved under the influence of natural selection in saline environments, in order to recognize characters that are likely to increase the fitness of plants in such habitats. Halophytes growing in coastal and estuarine ecosystems are of particular interest, because of readily available supplies of saline water and nutrients (with the possible exception of nitrogen). Coastal environments are nutrient sinks, and the tidal input of large quantities of water and mineral ions, represents an energy subsidy to these ecosystems (Odum, 1974). In arid regions, in contrast, the combined effects of drought and salinity present a formidable obstable to the breeder attempting to introduce varieties which will give an adequate yield.

Use of saline water in energy development

Abstract: Maps were made of the Upper Colorado River Basin showing locations of coal deposits, oil and gas, oil shale, uranium, and tar sand, in relationship to cities and towns in the area. Superimposed on these are locations of wells showing four ranges of water quality; 1000 to 3000 mg/l, 3000 to 10,000 mg/l, 10,000 to 35,000 mg/l, and over 35,000 mg/l. Information was assembled relative to future energy-related projects in the upper basin, and estimates were made of their anticipated water needs. Using computer models, various options were tested for using saline water for coal-fired power plant cooling. Both cooling towers and brine evaporation ponds were included. Information is presented of several proven water treatment technologies, and comparisons are made of their cost effectiveness when placed in various combinations in the power plant makeup and blowdown water systems. A relative value scale was developed which compares graphically the relative values of waters of different salinities based on three different water treatment options and predetermined upper limits of cooling tower circulating salinities. Coal from several different mines was slurried in waters of different salinities. Samples were analyzed in the laboratory to determine which constituents had been leached from or absorbed bymore » the coal, and what possible deleterious effects this might have on the burning properties of the coal, or on the water for culinary use or irrigation.« less

Growth of corn in saline waters

Abstract: Eight cultivars of Zea mays plus the wild species Zea diploperennis were screened for seedling saline tolerance up to 3.2% NaCl. The best performances were given by the cultivars Mo 17 and commercial Hawaiian Super Sweet Hybrid. These two were then field grown on coral-cinder beds using drip irrigation with fresh of half-strength sea water (1.5–1.7% dissolved solids). Growth and chemical data for Mo 17 at 12 weeks show reduced growth but the same percentage dry matter. Ash, protein and total sulfur were higher in saline plants, silica and total phosphorus lower. Na, K. Mg, and Cl were elevated and Ca reduced slightly. Fe was also increased in saline plants. Both Mo 17 and Super Sweet Hybrid corn flowered and produced seed which retained essentially normal viability both in fresh and salt water.

Alfalfa for Hydrologic Control of Saline Seeps

Abstract: Saline seeps affect extensive dry cropland areas in the northern Great Plains and methods need to be devised to control them. The effectiveness of alfalfa (Medicago sativa L.) in controlling saline seepage on northern Great Plains small grain dryland farms was studied from 1971 to 1977. Alfalfa, when grown on about 80% of the recharge area, reduced the deep percolation of soil water and provided hydrologic control for two seep areas within 1 year after its establishment in recharge areas. As the perched water table receded, the soil surface in the discharge (seepage) area dried allowing passage of farm implements, soil salinity decreased, and weeds, grasses, and crops grew better in the seepage area. In contrast, a buffer strip of alfalfa (occupying about 20% of recharge area) on the upslope side of a saline seep did not provide hydrologic control. Greenhouse data indicated that alfalfa yields will decrease rapidly if soil salinity increases to high levels above a saline water table. Reduced plant growth resulted when salts accumulated in the root zone as water moved upward by capillary action. When in situ root zone soil salinity reached an EC of 38 mmho/cm, alfalfa growth essentially ceased. We concluded that alfalfa can effectively control the hydrology of saline seep areas if it is grown on a major portion of the recharge area.

Growth and chemical composition of dry beans as affected by soil salinity and N fertilization

Abstract: The effects of three levels of N (0, 50 and 100 ppm) and four salinity regimes (0.5, 1.5, 2.5 and 3.5 mmhos/cm) on the growth and mineral composition of dry beans (Phaseolus vulgaris L.) were investigated in a greenhouse experiment. Bean plants treated with N produced more dry weight and contained higher N than the untreated check. Growth and N uptake by bean plants generally decreased with increasing irrigation water salinity at all N levels. High salinity caused severe burning of the margins of older leaves and stunting of growth. At the low salinity levels (0.5 and 1.5 mmhos/cm), N additions had no effect on growth; however, the suppressing effects of higher salinity were alleviated somewhat with N fertilization.

Irrigation of lucerne under semi-arid conditions in Cyprus.

Abstract: Three amounts of water −1.0, 0.8 and 0.6 of the irrigation requirement — were used to irrigate lucerne at two frequencies of application — once or twice during each growth cycle. Screened Class A pan evaporation, adjusted by monthly crop coefficients, proved a dependable guide for irrigation. Irrigating once per growth cycle was sufficient, and the highest yield was obtained when the full irrigation requirement was applied. The average annual dry matter yield for the three amounts of irrigation water — 1390, 1110 and 829 mm per year — was 20 285, 16 353 and 12 952 kg ha−1 respectively, i. e., yield decreased linearly with decreasing amount of water applied. As the water used was saline — with an electrical conductivity of 3 mmhos/cm−1 — the ‘main root zone’ became gradually salinized with the drier treatments, while with the wettest treatment salts accumulated below 80 cm depth. Yields were drastically reduced during the hot summer months, even when adequate water was available in the soil profile. This combined with the high irrigation requirement resulted in very low efficiency of irrigation during summer.

Nutrient pools of an estuarine ecosystem-the blackwood river estuary in south-western australia

Abstract: SUMMARY (1) The Blackwood River Estuary in south-western Australia contains essentially fresh water in winter, but stratified saline water in summer, as a result of a markedly seasonal climate. (2) This seasonal pattern not only influences the distribution and concentration of the major cations and anions, but also that of the major plant nutrients, nitrogen and phosphorus. (3) Phosphorus and nitrogen are at relatively low concentration during the summer saline phase and at high concentration during the winter freshwater phase. (4) The sediments contain high concentrations of these nutrients, relative to the concentrations in the water column, throughout the year. (5) The plant communities represent a large mineral-nutrient pool in the estuary. (6) The fringing plant communities liberate some of their nitrogen and phosphorus to the soil after death, and this is reflected in a correlation between soil-nutrient content and stage in plant succession.

Effect of varying Mg/Ca ratio and electrolyte concentration in the irrigation water on the soil properties and growth of wheat

Abstract: This paper discusses the results of a pot experiment conducted to study the effect of irrigation waters having varying Mg/Ca ratio (2, 4, 8 and 16) and electrolyte concentration (20 and 80 meq/l) on the soil properties and growth of wheat crop in two different soils. The development of salinity in the soils generally increased at higher electrolyte concentration of the irrigation water, but it was of a greater magnitude in the heavy-textured black soil dominated by montmorillonite clay mineral than in the light-textured alluvial soil having illite type of clay mineral. The accumulation of soluble salts as a result of saline water irrigation was higher in the surface layer than in the subsurface layer in both soils. The adsorption of Na and Mg in the soils increased with an increase in the Mg/Ca ratio and electrolyte concentration of the irrigation water. These changes in soil properties were adequately reflected by the grain and dry matter yields of wheat crop, which showed a significant reduction with an increase in the Mg/Ca ratio and electrolyte concentration of the irrigation water. However, the effects of these treatments were more pronounced in the heavy black clay soil than in the alluvial soil. Thus, the role of Mg is different from that of Ca under the conditions used in the experiment.

Behaviour of iron and manganese in the Yarra estuary

Abstract: The behaviour of iron and manganese in the Yarra estuary (a rather small, well-stratified estuary) is shown to be closely linked with the magnitude of the Yarra River inflow. When river flows are average to high, the filterable metals are present largely in bound or non-ion- exchangeable forms (iron > 90%, manganese 70-80%). Filterable iron levels in surface water from the estuary decreased with increasing salinity, and the filterable manganese levels firstly increased in the upper, low-salinity region of the estuary and then decreased with increasing salinity. Possible reasons for these changes are discussed. When low river flows existed, the concentration of filterable iron and manganese both increased markedly in the bottom, saline water of the estuary. Mixing of small amounts of these enriched bottom waters with outflowing surface waters resulted in the concentrations of filterable metal in surface water increasing with increasing salinity.

A proposal for reclamation by dilution of irrigation water

Abstract: A proposal is developed for reclamation of a soil which has become salinized from irrigation with saline water. The procedure permits continued irrigation after dilution of the saline irrigation water with higher quality water, which achieves partial reclamation without taking the land out of production, and without creating a large flux of drainage. Model calculations using a salt transport-chemical equilibrium model are performed for the case of a saline irrigation water derived from power plant cooling water residual (EC=4.2 mmho/cm), which is diluted by a high quality well water (EC=0.5 mmho/cm) to produce a water which is alternated with the saline water in cycles of two years. Soil salinity and drainage salt loads resulting under this system are compared with the simulated results of a more traditional method of salt leaching.

Reuse of Power Plant Cooling Water for Irrigation

Abstract: Current water quality policies in California require disposal of saline blowdown waters from power plants in sealed evaporation ponds to avoid degradation of ground waters. This policy highlights the conflict between increased energy demands, increasing scarcity of water, and environmental priorities. Saline blowdown waters can be used for the irrigation of salt tolerant crops, albeit with some reduction in yields. The results of experiments intended to specify these yield reductions are reported. If such irrigation is carefully managed, the soil profile can be used to store residual salts and ground water degradation will be avoided, provided that irrigation ceases before the salts are leached to the ground water. An analysis of discharge below a carefully managed irrigation project shows that the downward movement of salts below the root zone is no worse than with conventional methods of disposal. Thus, irrigation reuse with blowdown water is shown to be a viable means of saline water disposal while maintaining existing standards of ground water quality protection. Further analysis demonstrates the economic feasibility of such irrigation reuse by showing that it is significantly less costly than the evaporation pond alternative.

Storage of Freshwater in Saline Aquifers

Abstract: Studies were conducted to determine the salinity profiles in a freshwater layer stored over saline water in ground-water aquifers The one-dimensional difusion equation was taken as the governing equation and the diffusion coefficient was assumed to be dependent upon concentration Using this experimental data, the functional form of the diffusion coefficient was determined An implicit finite difference solution was used to solve the nonlinear diffusion equation The solution has been used to determine the salinity profiles in the freshwater layer

Characteristics and morphogenesis of salt-affected soils in southeastern arid Rajasthan

Abstract: Aerial photographs coupled with ground check and laboratory analysis have helped in mapping of four categories of salt affected soils located in the southeastern tract of arid Rajasthan. The categories are (1) Natural saline soils (2) Relict saline soils (3) Secondary salinized soils due to high water table and (4) Secondary salinised soils due to highly saline water use for irrigation