Salt Accumulation In Soil Research Articles

Effect of Irrigation Water Quality on Salt Accumulation in Soil and Mineral Contents of Alfalfa in the United Arab Emirates

Effect of Irrigation Water Quality on Salt Accumulation in Soil and Mineral Contents of Alfalfa in the United Arab Emirates

APPLICATION OF PESTFADE TO SIMULATE SALT MOVEMENT IN SOILS

This paper describes the application of a new solute transport model called PESTFADE (PESTicide Fate And Dynamics in the Environment) for simulating salt accumulation and leaching in soils. PESTFADE is a one-dimensional, transient, numerical model which can simulate water and solute transport in unsaturated, homogeneous soil systems. Also, the model considers the effects of dispersion, adsorption and macropore flow on solute movement. The numerical solution was verified with an analytical solution for a simplified case, and the model was validated using data from a soil column study involving irrigation with different amounts of total dissolved salts. Results from both the verification/validation runs indicate that PESTFADE can simulate salt movement in soils with good accuracy. Since the model can be run for different salinity, irrigation water management and drainage scenarios, it can provide information on appropriate water table management systems which can minimize salinity problems in arid and semi-arid regions.

Root dynamics of Melaleuca halmaturorum in response to fluctuating saline groundwater

Melaleuca halmaturorum is a salt and waterlogging tolerant tree and thus often occurs in saline areas fringing permanent wetlands and in ephemeral swamps. The dominance of this tree in natural groundwater discharge areas may result in M. halmaturorum transpiration making a major contribution to groundwater discharge. To quantify this the seasonal changes in tree water sources in response to fluctuating soil salinity and waterlogging were examined. This study was conducted in a natural system where seasonally fluctuating saline groundwater (64 dS m−1; 0.3–1.2 m deep) allowed the patterns of M. halmaturorum root water uptake to be followed over a 15 month period. Tree water sources were examined using the naturally occurring stable isotopes of water, while new root growth was examined using a field root observation window and from soil cores. The presence of isotopic fractionation of 2H under conditions of soil salinity and waterlogging was tested in a glasshouse experiment. Measurements of soil and leaf water potential were also made to examine the possible water sources and limits to water uptake. No isotopic fractionation was found by tree roots under conditions of salinity and waterlogging. M. halmaturorum trees were active in taking up groundwater at most times and combined this with a shallower soil water source replenished by rainfall in winter. Water uptake was concentrated in the deeper parts of the soil profile when the groundwater was at its deepest and salt had accumulated in the surface soils, at the end of summer. When groundwater rose, at the end of winter, roots responded by extracting water from near the soil surface (0–0.1 m), at the new watertable. This pattern of water uptake in response to groundwater fluctuations and salt accumulation in the surface soil was also reflected in new root tip appearance at the root observation window. Fluctuations in leaf water potential fallowed fluctuations in surface soil (0.1 m depth) water potential at all times. In winter leaf water potential reflected the absolute values of the surface soil water potential but in summer it was between surface soil and groundwater water potentials. We conclude that M. halmaturorum used groundwater in summer and a combination of rainfall and groundwater from the surface soils in winter. The ability to take up water from saline substrates through the maintenance of low leaf water potential, combined with this ability to rapidly alter root water uptake in response to changes in soil water availability contributed to the survival of M. halmaturorum in this saline swamp.

Fertilizer Application Method to Avoid Salt-Accumulation in Soil under Vinyl-House Cultivation

Fertilizer Application Method to Avoid Salt-Accumulation in Soil under Vinyl-House Cultivation

Salt accumulation in semi-arid floodplain soils with implications for forest health

Dieback of native Eucalyptus largiflorens forests is an increasing problem on the floodplains of the lower River Murray, southern Australia. Salinisation of floodplain soils, as a result of the changed hydrological management of the River Murray, appears to be a primary cause of the dieback. Regulation of the River Murray has reduced the frequency of large flood events by a factor of approximately three and caused groundwater levels beneath floodplains to rise. The higher water tables have resulted in increased discharge of the naturally saline groundwater in the floodplains by evapotranspiration, and the decreased incidence of large floods has reduced floodwater recharge and hence leaching of salt from floodplain soils. Use of soil physical properties for a range of floodplain soils, combined with measurements of groundwater discharge from bare and vegetated sites, suggests that the time-scale for complete soil salinisation can, at worst, be less than 20 years. Moreover, salt accumulation at most sites will continue to occur as the present flooding regime (of which there is limited scope for improvement) appears incapable of providing the leaching required to counteract accumulation. The analyses carried out here suggest that the ‘critical’ water table depth (below which groundwater discharge is balanced or exceeded by floodwater recharge) needs to be increased by 14–55% (the more clayey the soil, the larger the increase) to prevent salt accumulation. Failure to implement schemes which lower the water tables beneath the floodplain may, in the long term, cause serious damage to these important riparian forests.

Water utilization and soil salinity control in arid‐zone agriculture

Abstract Salinity problems are common in arid and semi‐arid regions, where rainfall is insufficient to leach salts out of the rhizosphere. In addition, these areas often have high evaporation rates, which can encourage concentration of salts at the soil surface. The presence of a caliche horizon and/or a cemented hardpan layer at varying depths, plus insufficient precipitation for leaching often adds to the salt accumulation in soils. Newly established irrigation projects, with improper planning and management practices, may also add salts to soils. However, soil salinity problems are present in nearly every irrigated area of the world and also occur on non‐irrigated croplands and rangelands. Thus, virtually no land is immune from salinization. Therefore, for sustaining life on earth, control of these problems and finding new ways to utilize these extensive saline soils and water resources, at least for agricultural purposes, are vital and urgent. Reclamation, or at least minimizing the effect of salinity...

An hypothesis concerning the development of the red leaf disorder in cotton (Gossypium hirsutumL.)

The development of the physiological disorder of cotton known as ‘rooidood’, ‘red leaf disorder’ or ‘potassium deficiency syndrome’ has not yet been explained. Several stress conditions have been associated with this disorder, including low N levels in leaves, low K levels in leaves and soils, high water table, soil compaction, salt accumulation in soil, wilting disorders, windy conditions and large boll loads. The plant's mechanism to avoid carbohydrate starvation in case of untimely stomatal closure, which is dropping of squares and young bolls, cannot function if only large developing bolls are present late in the season. The red leaf disorder may be the result of an alternative mechanism to avoid starvation of inabscisible bolls, to the detriment of assimilates and nutrients of unproductive leaves. All of the mentioned stress conditions associated with the disorder can cause stomatal closure. A large boll load or sink should aggravate the photosynthate shortage of the plant under any such stress. The ...

Water uptake of barley roots from rhizospheric soil solutions of different salt concentrations

Roots absorbing water from saline soils cause the rapid accumulation of soluble salts in the soil in close vicinity of the roots (rhizospheric soil). Thus the roots are in contact with a soil solution which is often several times more concentrated than that to be expected from average soil solution data. This paper describes a simple method to determine the reduction of the water uptake rate caused by salts in the rhizosphere.

Managing Salinity in Irrigated Agriculture

Excessive accumulation of salts in soils and ground water has plagued the irrigated semiarid and subhumid regions of the world for centuries. The structural measures of salinity control are effective but extremely capital intensive. A non-structural management model is presented which may help maintain a permanent irrigated agriculture at a reasonable cost. The model is based on the theory that an irrigated system consists of a number of components and that the good health of each component is vital to the overall good health of the entire system, and that ignoring even a single component could lead to disastrous consequences. A simplified limited version of the model is applied to a case study and it is concluded that the implementation of the model devised strategies could reduce the normal rate of degradation of the ground water by about 80 percent.

One Season's Salt Accumulation in Soil and Trees Adjacent to a Highway1

Abstract Soil and hemlock needle samples obtained in Fall, 1972 at various distances from the edge of a newly-opened section of Interstate-95 were analyzed for Na and Cl and compared with samples taken from the same locations the following year. Soil Na was significantly increased to distances of 12 m from the highway's edge after the salting season while soil Cl was increased to a distance of 61 m. Both Na and Cl increased significantly in needle tissue at distances up to 61 m after one salting season.

Salt Tolerance of Chickpea Varieties during Germination1

AbstractChickpea (Cicer arietinum L.) is grown extensively in Iran. The accumulation of salts in irrigated soils may reduce the germination, growth, and eventually the yield of this crop. Knowledge of variation in salt tolerance in chickpeas is important for assigning varieties to fit the soil.Effects of seven salinity levels (O to 2% NaCl) on germination of Iranian chickpea varieties, ‘Isfahan 11,’ ‘Ardebill 169,’ ‘Ardebill 174,’ and Ahar 174' were determined under controlled temperature (30 ± 2 C). Increased salinity reduced the germination of Isfahan 11 significantly more than Ardebill 174 and Ahar 174. Sodium chloride concentrations greater than 0.5% reduced the germination of all varieties significantly. The general trend in germination reduction with increased salinity was the same for each variety.

Influence of Cropping System on Salt Distribution in an Irrigated Vertisol1

AbstractField studies were conducted to determine the influence of cotton (Gossypium hirsutum L.) and grain sorghum [Sorghum bicolor (L.) Moench.] on salt distribution in a vertisol profile. Electrical conductivity of soil saturated pastes taken from the root zone (0 to 90 cm) after 4 years of sorghum ranged from 2.6 to 4.8 mmhos/cm but ranged from 4 to 7.6 mmhos/cm at 0 to 90 cm after 4 years of cotton. Chloride concentrations showed similar trends in that CI‐ concentrations were 9 to 12 meq/liter at 0 to 90 cm after sorghum, but were from 18 to 30 meq/liter at the same depth after cotton. The differences in salt concentrations in the soil profile after the two crops were attributed mainly to higher water infiltration rate after sorghum (5.81 cm/hr) than after cotton (1.23 cm/hr). The indicate that cropping practice can be an important factor in salt accumulation in clay soils and that the crops should be alternated to avoid excessive salt accumulation in the root zone.

Correlations between Constituents in Irrigation Waters and Irrigated Soils in Kansas

AbstractSoil and water from 26 sites from north‐central and southwestern Kansas were studied to determine if knowledge of the chemical composition of irrigation water could be used to predict salt and Na accumulation in soil. Samples were collected in the summer of 1958 and 1959.Mean exchangeable Na percentage in irrigated soils can be predicted with reasonable accuracy from constituents in irrigation water using Gapon's equation, soluble Na percentage, or the Na adsorption ratio as the basis for estimation. Exchangeable Na percentage can be estimated with an accuracy of ± 1.8 at the 0.90 probability level for 25 out of the 26 soils.Correlation between conductivity of soil saturation extracts and that of irrigation water was 0.98 when observations were restricted to soils that (a) increased in total salt content upon irrigation and (b) in which conductivity of the saturation extract exceeded that of irrigation water. Maximum irrigation water electrical conductivity used on such soils was 2.28 mmho per cm. For this value, soil saturation extract electrical conductivity could be predicted with an accuracy of ± 0.54 mmhos per cm. at the 0.90 probability level.Electrical conductivity of soil saturation extracts varied from 0.4 to 4.7 mmho per cm. at 25° C. Mean exchangeable Na percentage ranged from 0.1 to 6.2. Irrigation water ranged in conductivity from 0.3 to 4.9 mmho per cm. at 25° C.

The cyclamen mite,Tarsonemus pallidus, and its control on field strawberries

does not appear. First page follows. Introduction During the past several years, strawberry fields in California have shown an increasing decadence, until, at the present time, a commercial planting may be expected to produce a crop of fruit for two years, or in some cases only one year, and then become commercially unproductive. This is strikingly in contrast with the conditions which existed 15 or 20 years ago, when, according to reports, strawberry plantings produced crops for 4 to 6 years. This decadence may be caused by one or more relatively obscure factors, of which the most important is, no doubt, in certain varieties at least, the virus disease known as yellows or xanthosis. In addition, strawberries suffer from accumulation of salts in the surface soil, and from root diseases of obscure etiology. Recently Thomas (1932) has discovered that the causal agent of a hitherto puzzling wilt disease is a fungus belonging to the genus Verticillium. Among the animal parasites of strawberries are the cyclamen mite, red spider, the strawberry root-worm, white grubs (larvae of various scarabaeid beetles), the stem nematode, the root-knot nematode, and aphids. The most important economically of these parasites of strawberries at the present time is the cyclamen mite, Tarsonemus pallidus Banks.

The Formation, Evolution, Reclamation, and the Absorbed Bases of Alkali Soils

Summary1. The formation of alkali soils is primarily a question of soluble salt accumulation. Those processes which bring about the accumulation of soluble salts in soils also tend to cause the accumulation of CaCO3. Under certain conditions simple calcium silicates may also be precipitated in alkali soils. Hilgard's researches were concerned chiefly with the soluble salts. On the other hand, more recent investigators have emphasised the base-exchange aspects of the subject. Sodium salts tend to react with the clay and humus constituents of the soil, converting them into Na-absorption compounds. These components produce extremely adverse conditions in the soil.2. Under certain conditions alkali soils tend to pass through four evolutionary stages, namely, salinisation, alkalinisation, desalinisation, and degradation. As to whether or not an alkali soil will pass beyond the salinisation stage, depends on the composition of the soluble salts that accumulate in it. Where sodium salts predominate, more or less alkalinisation of the exchange complex has taken place. However, this is not true where soluble calcium is relatively abundant.3. Desalinisation (by leaching, whether natural or artificial) of alkalinised soil is usually accompanied by the formation of Na2CO3and by pronounced deflocculation. If CaCO3be present, the formation of Na2CO3is accompanied by the replacement of absorbed sodium by calcium. Under these conditions the degradation stage will not be attained. If CaCO3be absent, base-unsaturated constituents arise under leaching conditions, and more or less of the inorganic-exchange complex becomes decomposed into simple oxides.