JWSS - Journal of Water and Soil Science

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This study addresses the methodology of studying spatial variability of soil salinity. The information used is based on a semi-detailed soil survey, followed by a free survey, conducted in Ramhormoz, Khuzestan. The study of soil salinity variations was carried out using about 600 sampling points with an average distance of 500 m, at three depths of 0-50, 50-100, and 100-150 cm. To determine the spatial variability of soil salinity at different depths, the variogram which is a statistical function for the spatial variability analysis of the geographical variables was used. The results indicate that all variograms show almost the same range of 12 - 13 km which is closely related to the geographical distribution of the soil parent materials in the area. Ordinary block kriging was used to map salinity at different depths for a block dimension of 500 × 500 m. A comparison between the kriged estimates and the soil salinity map, produced during the soil survey, showed that the overall similarity between the test data and the classified kriging estimates was 40%, while the overall agreement between the test data and the soil survey salinity map was 36%. A detailed similarity calculation showed that the reliability of the classified kriging estimates representing the lowest salinity classes (S0, S1) is larger (75%) than the reliability of the soil survey salinity map representing these classes (50%). Consequently, the results indicate that geostatistical tools can be used to support the present-day procedures of soil salinity mapping.

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Life in central Iran depends on the Zayandehrood river, making the preservation of its quality important. Salinization and pollution of the flow as a result of different organic and inorganic pollutants create serious threats to the environment and to the agricultural activities in the region. Although the role of the main drains discharged into the Zayandehrood in changing its quality is well known, little information is available on the volume and quality of the discharged drains. The purpose of this research was to study the quantity and quality of three main drains (Zoab-Ahan, Rudasht and Segzi) discharging into the Zayandehrood, Monthly samples were taken from each drain and their chemical properties were measured in 1998. The discharge rates were also measured simultaneously at sections near the discharge points.

The results showed that all three drains were alkaline and, therefore, had no negative effects on the pH of the river flow. Mean annual EC of Zoab-Ahan, Rudasht and Segzi drains were 5.56, 27.18 and 42.41 dS/m, respectively, and the salt loads discharged into the river by these drains were 39258.4, 37672.9 and 259781.2 ton/year, respectively. Annual mean N concentrations were 4.49, 3.92 and 4.18 mg/L and annual mean P concentrations were 0.26, 0.16 and 0.12 mg/L in the drains, respectively. The most important effect of the drains on the Zayandehrood was salinization, especially in the lower parts of the river. The increase in soluble salt contents of the river after Segzi drain discharge was so high that it made the water thereafter unusable for any purpose.

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The effect of soil salinity on plant growth is due to two factors, namely, increase in osmotic pressure of soil solution and the ionic composition of salt. The present experiment was conducted to obtain information about the response of pistachio (Pistacia vera L.) to salinity and ionic composition of the salt. Salinity with different relative composition of sodium chloride and sodium sulfate were applied to two pistachio cultivars, Fandoghi and Badami. Yield (dry matter of leaf and shoots produced in each pot) of plants were compared by the analysis of variances method of F and Duncan tests.

The yields of the cultivars were significantly different (P≤0.01) with Fandoghi cultivar producing less shoots and leaf and, consequently, lower total dry matter. Increasing the salinity level decreased the plant growth. Leaves were more sensitive to salinity. Increasing the ratio of sulfate salt alleviated the depressive effect of salinity such that when salinity was 100% sodium sulfate, the dry matter yield of shoots was 1.5 times and that of leaf was 1.7 times higher compared to the treatment where salinity was 100% sodium chloride. Leaf was more sensitive than shoots and, therefore, it showed a more positive response to chloride decreasing.

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A glasshouse study was conducted to measure the effects of salinity and drought stresses on growth and chemical and biochemical composition of 4 onion cultivars. The cultivars were Dessex, Texas Early Grano (Texas), Dehydrator, and PX492. Salinity treatments included control, 45mM NaCl, 45mM NaCl + 5mM CaCl2 and drought treatments were control (maintaining soil moisture at field capacity) and irrigation when 50% of available water was used. Four weeks after the treatments, the plants were harvested and root and shoot dry weights (RDW, SDW), Na⁺, K⁺, Ca²⁺, total protein, reduced sugars, as well as free proline contents were measured in both roots and shoots.

 Results showed that NaCl and drought treatments significantly reduced SDW and RDW. The Texas cultivar and the Dessex cultivar produced the highest and the lowest amounts of SDW, respectively. NaCl significantly increased Na⁺ uptake but reduced K⁺ uptake in shoots and roots and also reduced Ca²⁺ uptake in roots. NaCl+CaCl₂ significantly alleviated the deleterious effects of NaCl such that SDW significantly increased in two cultivars and increased RDW and the K⁺ contents while causing decreased Na⁺ and sugar contents in shoots and roots of all cultivars. All stresses increased total protein contents of shoots in Texas only but decreased or had no effect on others. Root total protein increased under salinity stress, while drought had no effect. Changes in proline and sugars in both shoots and roots did not follow any particular pattern. Out of the biochemical compositions measured, shoot total protein in plants under the stresses showed a positive significant correlation with SDW, which may be used to screen onion cultivars for drought and salinity stresses.

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In order to increase ketocarotenoid astaxanthin production by Haematococcus pluvialis, the effects of salinity, phosphate deprivation and eosin on growth and astaxanhin production were examined. The experiments were carried out in the growth chamber at 20^oC under sterile conditions. The results showed that under salinity, phosphate deprivation and eosin supply, encystment was induced, and at the same time, astaxanthin formation and dry weight increased. Furthermore, by adding histidine to culture medium as a quencher of singlet oxygen, astaxanthin production significantly reduced. Therefore, it can be claimed that accumulation of astaxanthin may be related to antioxidative responses, which increased survival of algal cells under environmental stress conditions.

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In this study, the potential use of halophyte grasses, Aleuropus littoralis and A. lagopoides, on soil desalinization and lowering soil salinity was investigated under glasshouse conditions. The seeds of two species were collected from Rodasht area in Isfahan and grown with four salinity treatments obtained from different types of collected soils and replicated three times. Electrical conductivities of the four soil treatments were 12.4, 29.5, 43, and 69 dS/m. The results of mean comparison showed that shoot and root dry weight, sodium contents of dry weight and Na/K ratio were significantly different in both salinized species. Both species effectively reduced soil electrical conductivity by 23 to 42.5%. This was mainly due to ion absorbtion, and consequently, from Na⁺, Cl^-, Mg²⁺, Ca²⁺ ionic reduction. In general, considerable amounts of ionic absorbtion and total soluble salt secretion through their salt glands appeared to have the most pronounced effects on decreasing soil salinity. Regarding 50% salt excretion by these species, growing these grasses could be a possible way to decrease soil salinity by grazing or harvesting salt crusted foliage from the site.

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A factorial experiment with two levels of Zn (0 and 1.5 mg Zn kg^-1), five salinity levels of irrigation water (0, 60, 120 and 180 mM NaC1, and 120 mM NaNO₃) in three replications was conducted. Wheat (Triticum aestivum cv. Roshan) was seeded in pots. After plant harvesting, zinc and cadmium concentrations were determined in the shoot. Activities of metal species in the soil solution were predicted using the computer program MINTEQA2. Treating the soil with NaC1-salinized water increased total concentration of cadmium (Cd_T) as well as Cd²⁺, CdC1⁰₂, and CdCl⁺ species whereas, NaNO₃ treatment had no significant effect on Cd_T. Shoot Cd concentrations were positively related to Cd_T and soil solution Cl^- but negatively related to Zn_T. Application of Zn-fertilizer decreased Cd and increased Zn concentrations in shoot, significantly. The results of this experiment showed that Cl^- has an effective role in increasing mobility of soil Cd and its uptake by plant.

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In a pot experiment, the growth (Dry matter) responses of 18 rapeseed varieties to three levels of NaCl salinity induced by 1.2, 6, and 12 dS.m^-1 were investigated using a factorial experiment with a randomized complete block design in 3 replications. The results indicated that salinity reduced total dry matter, Na concentration, K/Na ratio, ion selectivity of K versus Na, and leaf water potential while it increased K concentration. However, the leaf water potential of the plants had the highest and a significantly negative correlation with total dry matter accumulation. Therefore, it seemed that leaf water content of the plants could explain the tolerance or sensitivity responses to salinity. The rapeseed varieties were accordingly ranked into different groups. The varieties viz, Alice, Fonax, DP.94.8 and Licord were classified as saline tolerant group, and varieties such as Okapi, Akamar and Eurol as saline sensitive group. The remaining eight rapeseed varieties were moderately tolerant. Moreover, the response of rapeseed varieties viz. Consul, VDH8003-98 and Orient were different such that the above explanation could not be applied to them. Therefore, halophytic strategies for these three varieties might be worth further investigation.

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Due to the existence of salinity and high temperature and sensitivity of some plants in most regions of Iran, especially in Khoozestan, there are a lat of difficulties in the planting and husbandry of lawn. Therefore an experiment was carried out under field conditions, to investigate the effect of seven levels of salinity as: Karun river water with EC of 1.09, distilled water (0.01) and irrigation with hand made salinity of 3, 6, 9, 12 and 15 dS/m on the growth and development of three types of lawn namely: Lolium perenne L. cultivar Barball, Festuca arundinacea cultivar Kentaky-31-C and Cynodon dactylon cultivar Primo in the form of a 7×3 factorial with a completely randomized design in 3 replication. A number of leaves on the main shoot and tiller, fresh and dry weight of leaves, leaf area and a number of tiller per plant were recorded. According to the results, it was revealed that the effect of salinity, Genus and interaction were significant (P<0.05) on growth parameters. In all salinity levels, Cynodon dactylon, in comparison to the other two genus displayed the highest rate of growth, while between the two other genus there were no significant differences. In addition, it was revealed that the number of leaf on the tiller and main shoot in Cynodon dactylon at a salinity of 15 dS/m was 5.1 and 4, respectively. Whereas in others, no leaves were initiated at this level of salinity. It was also appeared that at salinity of 15 dS/m, the growth of leaf area, the fresh and dry weight of leaves greatly decreased in Lolium perenne and Festuca arundinacea, while Cynodon dactylon still had growth ability. It was concluded that the number of tiller per plant and high of the plant was less affected by salinity, compared to the other growth parameters in all of genus.

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The Effect of various NaCl levels on the shoot content of trace elements, in the seedlings of five citrus species namely: Bakraei (Citrus reteculata X C. limetta), Volkamer lemon(C. volkameriana), Sour orange(C. aurantium), Sweet lime (C. limetta) and Mexican lime(C. aurantifolia), were studied in a glasshouse, by a randomized complete block design with factorial arrangement and four replications. One-year old seedlings of each species were grown in the pots, containing native soil (pH=8.2) and irrigated with water supplemented with 0(control), 20, 40 and 60 mM NaCl. At the end of experiment, the amount of Fe, Zn, Mn, Cu, Cl and B in shoots were determined. The amount of trace elements varied among the species even in the control plants (no salt). Salinity had different effects on the shoot content of trace elements. Salinity reduced Fe content in the shoot of all species except in Bakraii and sweet lime and increased the amount of Zn in the shoot of all species except in Bakraii. The Mn content was reduced in the all species but increased in sour orange. Salinity reduced the amount of Cu in the shoot of volkamerina but had no effect in the other species. The amount of Cl increased in the shoot of all species with salinity. Boron content in the shoot of all species except in sour orange, increased with low salinity level but decreased with increased salinity levels. However in sour orange, salinity in the all levels decreased the amount of B in the shoot of seedlings.

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Saline soils and halophytic vegetations are common features and part of the habitat pattern in deserts and steppes. The saline area is developing in arid lands. Investigation effects of halophytes on soil characteristics and adaptive mechanisms of the various halophyte types is essential for controlling saline environments. Juncus gerardi is a perennial grass-like halophyte and Halocnemum strobilaceum is a succulent halophyte shrub. The distribution of these species is mound like in the field. The soil samples of the mounds for investigating the effect of these species on plant root environment were compared with near regions in Korsiah saline area in Darab. Also the consentration some ions of live and dead organs and tissues of these species were studied for recognition of their adapive types. The results show that Juncus gerardi decrease salinity in 0-30 cm of topsoil, therefore the Ec decreased 37%. But salinity increased significantly in 30-60 cm depth. The identification of ions in plant tissues showed that the concentration of ions is low in dry matter. This is 0.33% of dry matter for Sodium. This is a way to rescue from dry conditions by selective absorption of ions. The comparison of root environment of Halocnemum strobilaceum with near regions showed a significant decrease in salinity in 0-30 cm and 30-60 cm depth decreased 27% and 40% respectively. The identification of ions concentrations in plant tissues reflect the high amounts of ions, therefore the plant tissues composed of 8.18% of Sodium. The comparision of ion concentrations in different live and dead tissues of plants a Significant increase of the amounts of ion in the dead tissues in comparison with the live tissues. Therefore this species excrete much quality of salts in their dead tissues and organs and so combat this problem.

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Limitation of suitable water resources is the most important problem of agriculture in Iran. Considering the condition of shallow and saline groundwater in many parts of Iran, and relative resistance of safflower to salinity, it is necessary to study the contribution of groundwater to water consumption of safflower. In this research, the effects of different water table depths and salinity of groundwater on contribution of groundwater to evapotranspiration of safflower were studied. The treatments were four levels of water table depth (50, 70, 90, and 120 cm), two levels of groundwater salinity (EC of 0.6, and 10 dSm^-1 ), and two irrigation regimes (irrigation with a depth of water equal to 75 percent of evaporation from water surface and frequency of 5 days, and no irrigation). The experiment was performed in a randomized complete block design with treatment combinations arranged in factorial manner and three replications. For fixing the water table in the pots (PVC pipe 200 mm in diameter and 120 cm high), a special equipment was built on the principle of Marriot bottle that was able to measure the contribution of groundwater to evapotranspiration of the plants. Results showed that salinity of groundwater, irrigation regime, and their interactions have significant effects on evapotranspiration of safflower. In addition, effects of water table depth, salinity of groundwater, irrigation regime, interaction of salinity and water table depth, interaction of water table depth and irrigation regime, and interaction of water table depth, salinity, and irrigation regime on evaporation from soil surface were significant. The ratio of contribution of groundwater to plant water consumption and evapotranspiration was in the range of 52.5 and 54.9% for saline groundwater and 81.7 to 82.7% for fresh groundwater. The ratio of evaporation from soil surface and evapotranspiration was in the range of 4.5 to 53.6% for different treatments. In all treatments of groundwater depths, irrigation treatment significantly decreased evapotranspiration, but no significant change in evapotranspiration was observed in irrigated and no irrigated treatments. Maximum amount of evapotranspiration (251 cm) occurred in the 50 cm depth of groundwater with salinity of 0.6 dS/m under irrigated condition, and minimum amount (43.9 cm) occurred in the 90 cm depth to groundwater with salinity of 10 dS/m under no irrigation condition. Generally, salinity of groundwater caused significant decrease in evapotranspiration, evaporation from soil surface, transpiration, and contribution of groundwater to evapotranspiration.

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Stabilizng sand dunes has been one of the main challenges in the arid regions. So far, different kinds of mulches have been used extensively for sand dune stabilization. This study was carried out to determine the optimum composition, concentration and thickness of clay mulch for sand dune stabilization. For this purpose two soil samples from clay flats of a playa with different amount of salinity from Ardestan area were used to make clay mulches. A sand dune sample was selected as bed for applying the mulch. To select the right ingredient and treatments, clay samples were mixed with sand and different amount of water, and sprayed on sand dune bed. In addition, wheat straw was added to some mixture to test its effect on stability of the mulch. Treatments with lowest crack and highest penetration of mulch in sand bed were selected for the experiment in this study. Mulch treatments contained (1): 250g sand dune + 250g clay + 25g straw (2) 250g clay + 25g straw (3) 250g sand + 250g clay (4) 250g clay (5) 125g sand + 125g clay and (6) 125g clay. All treatments were mixed with 500ml water. The experimental design was a CRD with a 6(mulch) * 2(thickness)* 2 EC factorial method with 3 replications. The results showed that clay mulch were resistant to wind erosion, but erosion took place when they had been bombarded with sandblast. The mulches with straw showed the highest resistance to erosion as compared to other treatments. With increasing the number of mulch layers, resistant to erosion also increased. The added stability of mulch was due to the increase in mulch thickness and also increases in clay and silt content. The overall result of this study shows that the mulch with two layers and higher mixture of clay and sands was the best treatment for the stabilization of sand dunes.

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In this paper, the effect of irrigation water salinity levels on seed germination, dry matter weight of seedlings at eight-leave stage, and the salt tolerance of 8 rapeseed cultivars was investigated. Relative yield reduction in saline and non saline conditions, salt sensitivity index and Van Genuchten-Hoffman methods were used to determine the salt tolerance of the cultivars. Results showed that the effect of different salt levels, cultivars and their interactions on germination and dry matter weight of seedlings was significant at 0.01(the higher the salt level, the lower the germination and dry matter). Also, using the Van Genuchten-Hoffman method, the irrigation water salinity corresponding to 10%, 25%, 50% and 90% reducts in germination and dry matter of seedlings were determined. Statistical analysis showed that a single cultivar gives different responses to salinity during growth stages and it may be tolerant in one stage, but sensitive to salinity in another growth stage. In this research, ACSN1, Falcon, and Shirali in germination stage and ACSN1, Falcon, and Cobra in seedling growth stage were salt tolerant. The three cultivars Oyerka, Global, and Ceres and the next three Shirali, Global, and Oyerka were sensitive to salinity in germination and seedling growth stages, respectively. Finally, the ACSN1 and Falcon cultivars were introduced as salt tolerant, and Oyerka and Global were considered as salt sensitive.

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In order to study the effects of salinity of irrigation water on the growth and quality of 10 bermudagrass cultivars under saline soil, a factorial plot experiment using a complete randomized block design with three replications was carried out at College of Agriculture, Isfahan University of Technology in 2002-2003. Ten cultivars under five levels of irrigation water salinity (3.30, 6.93, 10.2, 14.8, 17.8 dsm^-1) were studied. During experiment, visual appearance of color (1 to 9, best 9), and leaf area, shoot and root dry weights and length and number of stolones were measured. Results showed that salinity of irrigation water affected color of different cultivars, such that with increase in the level of salinity, color decreased. Cultivars showed better color in August, but lower color in January. Annual mean indexes showed that ISF2 and Tifdwarf had highest and lowest color, respectively. Also, with increase in salinity levels, leaf area, foliage dry weight, length and number of stolones reduced. With increase in salinity of irrigation water from 3.30 to 10.2 dsm^-1 root dry weight increased, but reduced in higher salinity levels. Due to significant interaction effects between salinity and cultivars for most traits, the responses of cultivars were different. Large differences observed between cultivars for most of traits indicated high genetic variation among the studied bermudagrass cultivars. Under high level of salinity conditions, JP2 and Tifway for foliage dry weight, 3200W18-4 and ISF2 for root dry weight, and cultivars Midlawn and 3200W18-4 for leaf area, were recognized as more tolerant than others.

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This study was conducted to evaluate the effect of salinity on concentration of potassium (K), sodium (Na) and chloride (Cl) ions, in sweet lime budded on five citrus rootstocks, including Bakraii (mandarin x sweet lime), Volcameriana, Sour orange, Sweet lime and Mexican lime in a glasshouse, using a randomized completely design with factorial arrangement and four replications. Rootstocks had great effect on the concentration of ions in scion. Concentration and distribution of ions were significantly different in control and other treatments. Salinity increased Na and Cl ions in shoots and roots, but the rate of increase varied among rootstocks and treatments. Lowest concentration of Na and Cl ions were in shoot of scion on Volkameriana. Under salinity stress, K concentration increased in shoots of scion on Sour orange and Bakraei and decreased it on other rootstocks. Salinity increased K concentration in roots of all rootstocks except for Mexican lime.

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In order to study the physiological responses of two barley cultivars to salinity stress, a 4-replicate CRD greenhouse experiment was conducted during at the College of Agriculture, Shiraz University, Iran2003-2004. The treatments consisted of two barley cultivars: Afzal and Reyhan and five salinity levels: 0, 4, 8, 12 and 14 dS/m. Seedling emergence, number of tillers and leaves per plant, leaf area and dry matter decreased with increasing salinity levels. The reductions were lower in Afzal (salt tolerant) than Reyhan (salt sensitive). A lower Na⁺ and higher K⁺Na⁺ in Afzal compared to Reyhan were observed under high level of salinity. The results of the present experiment also showed that the tolerance to salinity was associated with a greater stomatal conductivity, as well as transpiration and photosynthesis rate. Sub-stomatal CO2 concentration in both cultivars decreased with an increase in salinity, with the exception of 12dS/m, where it led to an increase in sub-stomatal CO2 concentration. Leaf temperature increased with an increase in salinity level in both cultivars, whereas a more pronounced decrease for number of fertile tillers, ears per plant, kernels per ear, thousand grain weight and harvest index was observed in Reyhan compared to Afzal .Since a higher tolerance to salinity in Afzal was apparently associated with a lower concentration of Na⁺ and a higher K⁺/Na⁺ ratio of the shoots, this trait could probably be used for yield improvement of barley cultivars under saline conditions.

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Inheritance of physiologicaly related salt tolerance traits including Na⁺ and K⁺ contents, K⁺/Na⁺ ratio of young leaves and biological yield (BY) in six basic generations (P₁, P₂, F₁, F₂, Bc₁ and Bc₂) and their reciprocal crosses derived from crosses between Kharchia × Niknejad and Shorawaki × Niknejad were studied in sand culture under high salinity treatment (EC = 22.5 dS m^-1). Generation means analysis indicated that a simple genetic model (including additive and dominance effects) is sufficient for Na⁺ and BY in Kharchia × Niknejad cross and for Na⁺, K⁺/Na⁺ ratio and BY in Shorawaki × Niknejad cross but, for other traits digenic interactions (additive × additive and dominance × dominance) were important parameters in the expression of salt tolerance of the various generations. Dominance genetic effects were predominant genetic components in most of the models. Weighted generation variances analysis suggested that dominance variance component was more important for Na⁺ and K⁺ content in both crosses. This result was confirmed by significant differences between back cross generations. Results also showed negligible dominance for K⁺/Na⁺ ratio in both crosses, multidirectional dominance for BY in Kharchia × Niknejad cross and absence of dominance gene action in Shorawaki × Niknejad. Kharchia × Niknejad cross showed, in general, more genetic variation, broad-and narrow sense heritabilities than Shorawaki × Niknejad cross, indicating the important role of primary differences between parents. These results revealed that recurrent selection followed by pedigree breeding or a selective diallel mating system may prove useful in improving salinity tolerance of wheat plants. The involvement of dominance × dominance interactions for some traits indicates that it is necessary to postpone selection for salt tolerance of wheat to advanced generations, when sufficient epistatic interactions have become fixed.

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The influence of Nitrogen (N) rates on mineral nutrient uptake in stem and seeds, proline and carbohydrate in flag leaves of Wheat (Triticum aestivum L . Var Chamran) under saline conditions was studied in a field experiment in 2003 and 2004. The experiment was conducted using a split plot design with three replications. The treatments comprised five levels of salinity: 1.5, 5, 10, 15 and 20 ds/m in main plot and three nitrogen levels: 50 , 100 and 150 kg N/ha in sub plot. Salinity treatments were applied in a clay–loam soil by water with NaCl and CaCl₂ (5:1 by wt ). The results showed, the nutrient uptake was influenced by both salinity and N treatments. With the Exception of magnesium in seed, salinity increased nitrogen, calcium and magnesium concentrations in seed and stem in both years. By increasing salinity levels, the concentration of potassium in stem and seed decreased and Sodium concentration increased. In the stem the concentration of Sodium in the 20 ds/m was about 17 and 22 times more in the first and second year, respectively. In these experiments, by increasing salinity and nitrogen treatments, proline concentration in flag leaves increased in the two stages (flowering and milky stages) in both years. Salinity had similar effect on carbohydrate accumulation in both stages, but nitrogen treatment had two different effects on carohydrate concentration. In flowering stage, by increasing nitrogen application, carohydrate concentration increased but in milky stage decreased.

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