JWSS - Journal of Water and Soil Science

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The effect of different media including the growth regulators on somatic embryogenesis from Mexican lime was studied. The average embryo formation after 60 days from unfertilized ovules in different media was evaluated at 0 to 33.75%. The most effective hormone to stimulate embryogenesis was GA₃ at 0.01 and 0.1 mg/l concentrations. Malt extract (ME) at 300 mg/l increased embryo formation, whereas at 1000 mg/l, it inhibited embryogenesis but produced embryogenic callus. Banzyl adenine (BA) at 0.1 and 0.01 mg/l concentrations had significant effects on embryogenesis, while embryo formation was inhibited at high concentrations. Embryo development in different media was also studied. The index of mean root length to mean stem length in the MT³ medium supplemented with 0.1 mg/l of GA₃ was observed to be 1.22±0.22, which was regarded a suitable medium for embryo formation, embryo development and plantlet regeneration.

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To study the effect of nitrogen, salinity and organic matter on growth and root morphology of pistachio (Cv. Badami), a greenhouse experiment was conducted. Treatments consisted of four nitrogen (N) levels (0, 60, 120 and 180 mg kg-1 soil as urea), four salinity levels (0, 800, 1600 and 2400 mg NaCl kg-1 soil) and three organic matter (OM) levels (0, 2 and 4% soil as farmyard manure). Treatments were arranged in a factorial manner in a completely randomized design with three replications. As the salinity levels increased, leaf, stem and root dry weights and root density, were significantly reduced. Addition of N up to 120 mg kg-1 soil, had no significant effect on growth, but the highest N level (180 mg kg-1), due to nutrient imbalance, reduced abovementioned plant parameters. In low salinity levels, N application improved the growth of pistachio seedlings, but at the highest salinity level, N addition didn’t suppress the adverse effects of soil salinity. Due to useful physical and nutritional properties of soil organic matter, addition of OM significantly increased leaf, stem and root dry weights, stem height, shoot/root ratio and root density.

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Tillage systems and organic manures could affect soil physical and mechanical properties. This study was conducted to investigate the impacts of two tillage systems including conventional tillage by moldboard plowing (plowing depth, 30 cm) and reduced tillage by disk plow (plowing depth, 15 cm) and three rates (0, 30 and 60 ton ha-1) of farmyard manure (FYM) on the soil penetration resistance under corn cropping in a split block design with 3 replications. The cone index (CI) decreased with increase of the tillage depth. It is attributable to soil disturbing and loosening of the deeper layers under conventional tillage compared to reduced tillage. This trend, however, was observed only in the first (after treatments’ application and before cropping) and second (the highest rate of vegetative growth) samplings. In the third sampling (after harvest), there were not significant differences between the CI values under two tillage systems in different soil depths. It might be due to soil re-compaction (approaching the pre-tillage state) as well as disappearance of the tillage effects seven month after commencement of the experiment. In fact, the soil mechanical resistance increased with the time indicating soil re-compaction over the growing season. Adding FYM to the surface layer (i.e. 0-10 cm) of ridge soil resulted in significant decrease of soil mechanical resistance compared to control treatment. The CI decreased significantly in the 30 ton ha-1 treatment up to the stage of highest rate of vegetative grow, but the effect on CI was diminished after harvest. However, the decreasing effects of the 60 ton ha-1 treatment on the CI continued to the harvesting time. There were no significant effects of FYM in the soil deeper than 10 cm from the ridge surface and in all of the layers in furrow. The CI did not decrease significantly in the furrow due to negligible effect of manure application for the inter-row position.

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Organic matters are the most important factors that affect soil compactability and physical characteristics. In order to study the effect of pistachio waste on physical characteristics of two soils, a factorial experiment was conducted in a completely randomized design with three replications in a greenhouse. The treatments included pistachio waste at 4 levels (0, 3, 6 and 9 w/w %) and two types of soil texture (silty clay loam and sand).The results showed that the bulk density of sandy soil was decreased at high levels of waste application before compaction but had no significant effect on the bulk density of clay soil. The penetration resistance of both soil types was decreased by pistachio waste application. Soil water holding capacity increased and moisture curves shifted up for higher levels of organic matter application, while compaction curve reciprocally shifted into the lower levels by incorporation of wastes into the soils. At higher levels of organic matters, maximum bulk density was decreased and critical moisture was increased specially in fine texture soil. After compaction, the application of pistachio waste significantly reduced penetration resistance in silty clay loam soil relative to control but in sandy soil its effect on penetration resistance was only significant at maximum level (9 %).

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Calcareous and gypsiferous soils are restricting factors for uptake of some plant nutrient elements and plant production. Most soils in Iran are calcareous and gypsiferous. Therefore, the aim of this study was the evaluation of calcium carbonate (Caco3) and gypsum effect on availability of some nutrients and corn growth. This study was conducted in a greenhouse at Vli-e-Asr University of Rafsanjan. Treatments were arranged in a factorial manner as a completely randomized design with three replications. Treatments were three levels of Caco3 (0, 20 and 40 g/100g soil), gypsum at three levels (0, 15 and 30 g/100g soil) and two soil textures (Sand and Silt clay loam). Results indicate that irrespective of soil texture, Caco3 application significantly decreased leaf area (by 80% and 15% for sand and silty clay loam texture, respectively), dry weight (by 80% and 15% respectively), plant height (regressed on Caco3 percentage by slopes -0.7 and -0.15 for sand and silty clay loam respectively), and shoot Fe (-9.67 and -11.3) and Zn (-0.24 and -1) uptake, but had no significant effect on shoot Cu uptake. In sandy soil, application of gypsum, significantly decreased leaf area (80%), dry weight (62%), and shoot Cu uptake (slope= -1.93), but had no significant effect on plant height and shoot Zn uptake. Gypsum application significantly reduced shoot Fe uptake (slope= -24.86) in fine textured soil, but it had no significant effect in coarse textured soil.

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In order to assess the effect of drought stress and various levels of potassium on solutes accumulation and chlorophyll of canola and Indian mustard, a field experiment was conducted in a factorial design based on randomized complete block design with three replications including three irrigation regimes (I1=irrigation after 50% depletion of soil water(control),I2 =irrigation after 70% water depletion and I3 =irrigation after 90% water depletion), two species (Hyola 401 hybrid of canola and landrace cultivar of mustard) and three levels of potassium fertilizer (K1=0 ,K2=150 and K3= 250 kg.ha-1 K2SO4 ) at Agricultural and Natural Resources Research Center of Sistan in 2008-2009 cropping season. Water stress increased proline and soluble carbohydrate accumulation in the leaves of Brassica sp. In non stressed condition (control) in different growth stages, proline was lower than water-stressed plants and Leaf proline content decreased significantly after irrigation. Mustard landrace showed higher capability for accumulating assimilates such as proline, soluble carbohydrates and potassium than hybrid Hyola 401. Water stress decreased the amount of chlorophyll a, b and total leaf chlorophyll, but Potassium application caused an increase in the mentioned parameters. The highest content of chlorophyll pigments was observed at flowering stage. Potassium application caused a decrease in proline and an increase in soluble carbohydrates concentration in the leaf under water stress condition. There was a negative correlation between grain yield and proline content and soluble carbohydrates, but grain yield was positively correlated with chlorophyll, a, b. It was concluded that osmotic adjustment can be an important mechanism for Brassica species under water stress conditions and that organic and inorganic compounds such as proline, soluble carbohydrates and potassium play key roles in this regard.

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Field capacity and permasent wilting point are the most important parameters in designing and programming irrigation, whose measurements are troublesome and time-consuming. But these parameters could be estimated by easy data characteristics such as soil texture, organic matter and gypsum, using Pedotransfer Functions (PTFs) with high precision. In order to estimate soil moisture at FC and PWP by easy data characteristic, using neural network (ROSETA) and regression models ,20 soil samples with 6 replications were collected from around Bardsir area in Kerman province and the charactersifics including, bulk density, clay, sand, silt, FC, PWP,T.N.V and organic matter were determined for each sample. The results showed that progress in neural network from a low level up to higher level needs new inputs (charactersifics), but without any considerable increase in the precision of prediction. Also, regression analysis for estimation of linear models to predict FC and PWP showed that PWP has a significant positive correlation with clay, and FC significantly correlated with sand, silt and clay. Therefore, two prediction models were constructed for FC and PWP with (R2= 69.2) and (R2= 76.6), respectively.

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Copper is considered as one of the most important nutrient elements for plants. If its contents are concentrated higher than the standard value it can be considered as a pollutant element. The content of absorbable copper in the area around Sarcheshmeh copper mine can be significantly high. In this study, samples of soil were collected in summer through a particular sampling method with chimneys of Sarcheshmeh plant as the center of sampling area within a radius of 6km, in three different directions (Rafsanjan, Sarcheshmeh City and Sarcheshmeh mine) and. The total concentration of absorbable copper and some chemical properties of soil (i.e. pH and EC) were measured for 122 surface samples (depth of 0 to 35 cm). There was a significant negative regression between pH and total absorbable copper content, and a significant negative regression was observed between EC and total absorbable copper content. The best fitted model was spherical model, and Ordinary Kriging was applied to map the absorbable copper content. Results showed that most concentration of copper occurred in the Rafsanjan direction. Also, regarding wind orientation which blows towards Rafsanjan, the chimneys probably have a significant effect on increasing copper content in Rafsanjan moreover, the copper content is substantially higher around chimneys than other areas. Also, transition of copper elements from chimneys by wind can be significant up to 4 km from Sarcheshmeh plant.

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This research was conducted to study the effect of natural and polyacrylamide-modified montmorillonite on the sorption of Cd from aqueous solutions. The sorption of Cd on the sorbents was studied as a function of pH (Cd concentration: 10 mg L-1) in the range of 4-8.5, and as a function of metal concentration (Cd concentration in the range of 1-10 mgL-1) using a 24h batch equilibration. Experimental and modeling data from equilibrium investigations revealed that the Koble–Corrigan sorption model describes the interaction between Cd and the two sorbents better than the Freundlich and Langmuir models. The values of KF constant of Freundlich and KL constant of Langmuir models were higher for sorption of Cd onto the modified montmorillonite than for those of natural montmorillonite. Maximum sorption capacity calculated from the Langmuir model was 0.6 and 0.7 mg g-1 for natural and modified montmorillonite, respectively. These values are indications of high sorption affinity of Cd to montmorillonite in the presence of polyacrylamide. The amount of Cd sorbed by modified montmorillonite decreased by increasing solution pH while Cd sorption by natural montmorillonite increased by increasing the solution pH.

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In this study, the effect of soil structure under saturated and unsaturated flow conditions on nonreactive bromide (BR) transport was investigated. The soil structure treatments consisted of undisturbed columns (prismatic and granular structures), and disturbed columns (single- grain structure). A constant concentration (C0= 0.005 M) of bromide was supplied on the surface of the columns in a steady-state flow condition. For the saturated flow condition, a flux equal to the highest saturated hydraulic conductivity (Ks) of the columns was applied on all of the columns. To create the unsaturated flow condition, a flux equal to the half of the lowest Ks of the columns was imposed on all of the columns. The leaching of the columns was followed for five pore volumes (5PV) and the bromide concentration of the effluent was measured at 0.2PV intervals using bromide selective electrode. The breakthrough curve (BTC) of single- grain structure was sigmoidal (S-shaped) and similar to piston-capillry flow form. In contrast, BTCs of the granular and prismatic structures had a steep initial part and later gradual tailed part. The preferential pathways caused the early appearance of bromide in the leachate of columns of these two structures. Tailing of the BTCs might be due to dispersion and diffusion between mobile and immobile water fractions. In saturated condition, the bromide plume appeared earlier than that in the unsaturated condition because of domination of mass flow and rapid macroporous stream. The results demonstrated the importance of soil structure, preferential pathways, and flow conditions in solute and pollutant transport.

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In recent years, due to the increased population, urbanization and changes in human consumption patterns, urban, industrial and agricultural soils have been exposed to various pollutants such as heavy metals. The objective of this research was to identify hotspots of Pb by using global and local Moran Indices in urban and suburban soils of Kashafrood catchment. A total of 261 surface soil samples (0-15 cm deep) were taken using irregular girding network method and their total Pb concentrations were measured. The positive Moran index at confidence level of more than 99 percent showed the spatial clusters between observations. On the basis of local Moran index results, 15 samples were introduced as hotspots (high-high value) located southeast of Mashhad plain. Exclusion of extreme values resulted in the addition of high-high cluster (hotspots) leading to the extension of these areas to the West of the Mashhad city. These areas are introduced as hotspots due to the urban land use, the direction of prevailing wind, and the area being close to Mashhad airport.

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Salinity and ions toxicity are one of the main problems of agricultural lands in arid and semi-arid regions, such as Iran. In addition to the salinity problem, some other marks like boron toxicity in crops have been seen in Hossein Abad area as one of the main agricultural regions of Yazd. Therefore, this study intends to evaluate and analyze spatial variability of soil salinity as an aspect of soil degradation, and prepares soil salinity and boron maps. A regular grid sampling scheme was done through a 150 m interval. Salinity and boron were measured at the depth of 0 to 30 cm. Totally 104 samples were measured. After statistical analysis of the data and studying their distribution, Kriging estimator was used for mapping the mentioned variables. Results showed that the region has a salinity problem and does not have any boron toxicity. According to the relationship of nugget effect and sill, there was a strong dependency among all the measured factors except for boron and pH factors. The least salinity was observed in cultivated areas due to the leaching process. The boron range was between 0.07 and 1.6 mg kg-1. Salinity and soil boron were significantly correlated at 99 % confidence level. Based on the Spearman and Pearson tests, there was a positive correlation between SAR and salinity at 99 % confidence level, which shows the region has more sodic salts than others. Also, pH of the region did not present any problem for growing crops.

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This research was conducted to prepare landslide susceptibility zonation (LSZ) map for the Dez-e-Ouliabasin using logistic regression model. For this purpose, at first, the most important factors affecting land sliding including slope, aspect, elevation, precipitation, the distance from road, the distance from fault, the distance from drainage, land use, and lithology were determined. Then, thelandslide inventory mapwas preparedby using field digital checks, GPS and satellite images. In the next step, the landslide susceptibility zonation mapwas preparedby usinglogistic regression method. According to the obtained coefficients for LSZ maps, the most important factor in the study area was elevation layer. The Receiver Operating Curve (ROC) index value was calculated (0.92), which indicates a very high level and suggests thatthe observed mass movements have a strong relationship with the logistic regression model.

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This experiment was conducted to evaluate the effect of vermicompost, pistachio kernel and shrimp shell on the immobilization and availability of Cd, Pb and Zn in corn in polluted soils. Treatments consisted of two levels of pistachio kernel, shrimp shell and vermicompost (5 and 10 % w/w). In control treatment, no amendment was added to the soil. The experiment was carried out as a completely randomized design with 3 replications. Plants grew for two months in the greenhouse. Then, all the plants were harvested and their shoots and roots were separated, washed with distilled water and oven dried at 65 °C to a constant mass. The measured characteristics were dry weight of shoots and roots, leaf area, greenness index, chlorophyll fluorescence, maximal quantum yield of PS  photochemistry (Fv/Fm), performance index (PI), and total concentrations of Cd , Pb and Zn in shoots and roots. Results showed that plant growth parameters (dry weight of shoots and roots, leaf area) and photosynthetic characteristics (chlorophyll fluorescence, Fv/Fm, and PI) were higher in plants grown in vermicompost and pistachio kernel treatments as compared to those grown in control. Plants died in shrimp shell treatment after two weeks. The concentration of Cd, Zn and Pb in shoots and roots of plants grown in vermicompost and pistachio kernel treatments were lower than those grown in control.

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Landslide susceptibility mapping is essential for land use planning and decision-making especially in the mountainous areas. The main objective of present research is to produce landslide hazard zonation at Sarkhoun basin in Karoon basin using two statistical models such as an index of Shannon’s entropy and weight of evidence and to assess the obtained results. At the first stage, landslide locations were identified in the study area by interpretation of aerial photographs, image sattellites, and from field investigations and then landslide inventory map was created for study area. The landslide conditioning factors such as slope degree, slope aspect, altitude, lithology, land use,distance of road, distance of fault, distance of drainage, topographic wetness index (TWI), Convergence Index, and precipitation were extracted from the spatial database and they were digitized in GIS environment. With integrated variables, landslides were calculated in each variable class and ‎weighted in index of entropy and weight of evidence model. In the last, landslide hazard zonation map ‎were obtained with both of models. The results of landslide susceptibility mapps of both statistical models were indicated more than 70 percent the occurred landslides were located in very high and high zones that about half of the basin area (over 45 percent) constitute. Also, the results of both models together were revealed that land use, has the greatest impact on the occurred landslides. Resolution of the zones, based on the seed cell area index (SCAI) and frequency ratio (FR) were evaluated suitable for both statistical models. Finally, the ROC (receiver operating characteristic) curves for landslide susceptibility maps were drawn and the areas under the curve (AUC) were calculated. The verification results of both models were evaluated very well and showed that the index of entropy model (AUC=89%) performed slightly better than weight of evidence model (AUC=82%).

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Recent urban development and population growth in Shahrood tend to adopt a strategy for ground water management. This project, which is a descriptive- analytic type study based on field observation and laboratory analysis, aims to delineate proper sites for groundwater artificial recharge using integrated AHP-TOPSIS.  First, the study area was delineated using remote sensing techniques. Then, appropriate criteria including 5 main criteria and 12 sub-criteria were obtained by field observation and literature review. Then, the appropriate sites for groundwater recharge were determined. The process of the used method consists of designing hierarchical structure of the project, preparation of pairwise comparison matrices, weighting criteria and sub criteria values by experts, and ultimately ranking them by TOPSIS method. Results showed that lithology, slope, water table depth, and land use have the main role in sites delineation. A number of control sites were employed for model validation that indicates 87.20 percent accuracy. Overally, 73.6 and 82.12 percent of the total area were grouped as very suitable and suitable classes, respectively.
 

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