JWSS - Journal of Water and Soil Science

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In order to investigate the cumulative effect of three-year application of municipal solid waste compost (C) and the compost accompanied with chemical fertilizer (CF) on the concentrations of some heavy metals in various organs of rice plant, a field experiment with completely randomized design in three replications was performed in 2009. Treatments were as follows: Control (without C and CF), CF (100 kg urea, 100 kg super phosphate and 100 kg potassium sulphate per ha), 15, 30 and 45 tons of C without CF, 15, 30 and 45 tons of C with 25%, 50% and 75% CF. Results showed that application of compost in three years would increase the amounts of Ni, Pb, Cd and Cr in different organs of rice plant. Also, application of C accompanied with CF increased the amount of Ni, Pb, Cd and Cr in various organs of rice compared to C. The highest concentration of nickel and lead (9.1 and 7.8 mg.kg-1 respectively) were obtained in grains in 45 ton C + 50% CF per ha treatment. Meanwhile, the maximum content of cadmium in grain (1.6 mg.kg-1) in 30 ton C + 75% CF ha-1treatment, and the highest amount of chromium in grain (1.8 mg.kg-1 ) resulted from 30 ton + 25% CF ha-1treatment.

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Continuous decline of groundwater quality for agricultural purposes has become a major concern in extensive arid and semi-arid regions. Therefore, mapping the quality of groundwater on a broad scale is an essential step in land management. This study aimed to map spatial distribution of two important groundwater quality indices including EC and SAR in Isfahan province, Iran, using geostatistical techniques. Different techniques such as Kriging, IDW and RBF were applied to water quality data of 540 groundwater wells to map continuous variations of the EC and SAR indices in Arc GIS 9.3 environment. Among the interpolation methods, the Kriging by circular variogram model performed best and had the lowest RMSe error. Therefore, the produced maps from this technique were classified based on Wilcox method. Results showed that EC varies across the province from 392.2 in the west to about 17917.6 µmmhos/ cm in the northwest and eastern parts of the study area. The highest and lowest SAR values were estimated in the towns of Khour va Biabanak and Semirom, ranging from 38.9 to 0.13, respectively. According to the map of irrigation water quality based on Wilcox method, about 12.13 % of the region was classified as good, 16% as moderate, 17.5% as unsuitable and 54.35% as unusable category. In general, the quality of groundwater in Isfahan province decreases from west to east and also from south to north, especially in playas (non-agricultural lands) where the unusable class is dominant.

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Drought is a one of the most important natural disasters that have high socio-economic and environmental impacts. However, drought is more than a physical phenomenon or natural event. Its impact results from the relation between a natural event and demands on the water supply, and it is often exacerbated by human activities. The traditional approach to drought management has been reactive, relying on crisis management. Due to the drawbacks of crisis management, employing proper risk management techniques has been suggested. In order to move from crisis management to risk management, in this study, risk of drought in Isfahan province was evaluated. Drought hazard index and vulnerability index are components of the drought risk management. Standardized Precipitation Index (SPI) was used as the index of drought hazard. For the calculation of SPI, the monthly rainfall data in 47 meteorological stations during the period of 1975-2007 were collected. The time series of rainfall data were prepared and for calculation of the standardized precipitation index in a 12 month timescale they were imported to SPI program. Percentage of drought occurrence in each severity was calculated and then the drought index map was obtained. Vulnerability index was calculated through socio-economic indicators (population density and percentage of people involved in agriculture), and physical indicators (available water capacity of soil and land use). Weighted Linear Combination (WLC) technique was applied for combination of vulnerability indicators. To assign weights to the criteria, an Analytical Hierarchy Process (AHP) was used. After providing the maps, fuzzy membership functions for every criterion were used for their standardization. For the weighting of the criteria, a questionnaire was prepared and criteria comparison was done using the participatory approach by a group of experts. Finally, the drought risk index was calculated by multiplying the drought hazard index and vulnerability index. The results showed that hazard of very severe drought is mainly concentrated in the central part of province. The North and North East of Isfahan province could experience condition of severe drought. South West of Isfahan province is under moderate drought condition compared to the other parts of the province. Map of drought vulnerability index showed that the most vulnerability is in the West, South and North-East of province. Map of drought risk index showed that the Northern Province demonstrated high risk. To reduce the drought risk in Isfahan province, improving monitoring, early warning, increasing environmental awareness, and promoting water resource management practices should be considered.

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In a pot experiment, the effect of soybeans, mung beans and beans on the corn and sunflowers in a cadmium contaminated soil was studied in a completely randomized design with three replications. The treatments consisted of intercropping of corn and mung bean corn and beans, corn and soybean, sunflower and mung bean, sunflower and beans, sunflower and soybean monoculture of corn, and monoculture of sunflower. There were significant effects of cocropping of companion crops on shoot dry weigh, the concentration of cadmium and zinc and the chlorophyll content of corn and sunflower. In this study the shoot weight of corn grown with bean and soybean and that of sunflower grown with bean plants was decreased as compared to the related monocultures. The concentration of cadmium was increased in the corn grown with soybean or mungbean and in sunflower grown with soybean. Co- cropping with bean plants had no significant effects on the concentration of cadmium in corn or sunflower. Among companion crops, the concentration of cadmium was higher in bean plants compared to those of soybean and mungbean plants. The chlorophyll content in the leaves of corn plants grown with mungbean was increased with an increase in cadmium concentration. However, this trend was not observed in other treatments. The results of this study show that co- cropping with either soybean or mungbean may increase cadmium uptake by corn and sunflower which in turn may increase the risk of inflowing of toxin cadmium into the food chain. However, further study needs to re-evaluate the effect of these companion crops on the distribution of cadmium in the edible parts of corn and sunflower.

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Intermittent irrigation of paddy fields with long intervals can cause cracks in heavy soils, facilitate loss of water and finally damage the crop. This study was carried out in order to investigate the cracking trend and some other factors affecting soil cracking in four different physiographical areas of paddy field. The study areas were Rasht, Shanderman, Astaneh and Khomam in Guilan province. The experiment was carried out in paddy fields with transplanted rice by determining the physical properties relevant to cracking behavior after irrigation withdrawal in the reproductive stage. Soil analysis showed that despite similarity in type of dominant minerals, the linear expansion coefficients of Rasht and Khomam soils were higher than those of two other areas. In addition, there was a significant relationship between crack dimensions and volumetric soil water content and clay content. Furthermore, the temporal variation in study of crack development (depth, width and density) showed that they varied in different areas and were affected by volumetric soil water content and the groundwater depth. In addition, the depth of cracks in all soils did not reach the hard pan. All the investigated soils showed a definite threshold for width and depth of cracks for 20-25 days after irrigation withdrawal. After this period, specific values for width (about 3.0, 2.0, 2.5, and 5.0 cm) and depth of cracks (20, 25, 17, and 27 cm) were registered for Astaneh, Khomam, Shanderman and Rasht, respectively

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Salt with various kinds and contents is one of the most important factors affecting soil splash erosion rate. The aim of the present study was to evaluate various salinity and alkalinity levels on splash erosion rate and its components (upslope, down slope and total splash) in different slopes. A factorial experiment with three factors was conducted in a completely randomized design with three replications by a Multiple Splash Set (MSS). The treatments included splash erosion rate at 4 levels of salinity and alkalinity (EC: 2 dSm-1, SAR: 2، EC: 15, SAR: 24 ،EC: 56, SAR: 42، EC: 113, SAR: 47), two levels of rainfall intensity (2.5 and 3.5 mm.min-1) and 5% and 15% slope levels. The results showed that the organic carbon and mean weight diameter (MWD) decreased at higher levels of salinity and alkalinity. The effect of saline and sodic, slope and rainfall intensity levels on the splash erosion rate and its components was significant. Also, slope×saline and sodic, rainfall intensity×saline and sodic, slope×saline and sodic×rainfall intensity interaction treatment caused a significant increase in splash erosion rate and its components. It seems that splash erosion is increased in saline and sodic soils due to the reduction in OC and MWD

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Determine appropriate locations with accuracy and speed required is for Floodwater spreading very important. The main objective of this research, preparation, use and evaluation decision support systems is based on GIS and RS techniques to identify and prioritization appropriate areas Floodwater spreading in the study area. In this study area suitable for flood water spreading were selected based on major criteria four, sub criteria eight and index twentyfour. Finally five scenario will be provide and assessment (a scenario based on the relative values for the criteria four, and different scenarios four based on the obvious one of the main criteria). Comparison desirability average among the scenarios five indicate that it is Sub watershed (1) In the scenario third (infilteration preferred, water application preference and equality of all the main criteria) had a higher average desirability therefore between Sub watershed 2 in this scenario is preferred more than the other Sub. Of between the two sub watershed ivar region considering that the desirability average, sub watershed (1) and implemented of between scenarios, scenario (1) (infilteration major criteria preferred) were selected as first priority. Second priority for Floodwater spreading site selection is belong to sub watershed 2, and with scenario (1).

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Evaluation of hydrologic behaviour and soil erosion as an environmental crisis is important in order to maintain watershed ecological safety at optimum level. The aim of this study is to evaluate the performance of the distributed hydrological WetSpa model in simulating erosion and sediment transport and also sedigraph in Taleghan watershed, Iran. Base digital maps and daily meteorological time series data for 9 years are the major model inputs. The calibration of global parameters was done for the first 5 years and the model validation was carried out for 4 years considering three month warm-up period at the beginning of both calibration and validation periods. The Nash-Sutcliffe criterion for the calibration and validation periods pointed out the efficiency of model simulation (82.7% and 79%, respectively). The next phase, the erosion module was calibrated for erosion and sediment transport simulation. The results showed the Nash-Sutcliffe efficiency criterion (60% and 64% for suspended sediment concentration and transport, respectively). Overall, the evaluation results reveal the good ability of WetSpa model in simulation of the hydrological processes e.g., runoff, raindrop detachment, runoff detachment, net soil loss, etc., in a given time and space

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In order to study the effect of depth of drip placement in soil in subsurface drip irrigation, and fertilization time during irrigation events, on tuber yield of potato, an experiment was carried out in Jiroft area in 1389. This experiment was in a completely randomized block design with four replications, with depth placement of drip tape as the main plot, and fertilization time as the sub-plot. Results showed that depth placement of drip tape had a significant effect on tuber yield, plant height, number of stems, stem diameter and dry plant weight at 1% level, number of tubers in plant, and wet plant weight and stolen height at 5% level. Fertilization time had a significant effect on tuber yield, stem diameter, stem number in plant, and plant height at 1% level and on dry plant weight and plant tuber number at 5% level. But, it did not show any significant effect on other attributes. Also, interactional effects of treatments were significant on tuber yield per plant, stem diameter, plant height, and number of tubers at 1% level, and on dry plant weight at 5% level, but the effect on other traits was not significant. According to the statistical results, the highest yield was obtained from the depth of 15 cm and middle time of fertilization.

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Advance velocity is an important factor in surface irrigation system design and simulation. Volume balance is a simple model based on continuity equation used in surface irrigation design and management. In the past volume balance models, it is generally assumed that the upstream depth of surface water is constant and equal to normal depth. This initial assumption may cause significant errors in computing advance flow. In this paper, a modified volume balance (MVB) model is developed to predict the advance curve in furrow irrigation. In the suggested method the upstream surface, water depth is actual depth and variable in time. Predicted advance distance of VB, VB-ZI and MVB was compared to the observed data obtained for the three furrow lengths of 60, 80 and 90m. Evaluation indexes indicated that the modified volume balance equation is more accurate than the previous equations by RMSE 9.26, 7.37 and 6.76 respectively. Sensitivity analysis showed that the inlet discharge has the greatest effect on the model and the model is more sensitive to decreasing the discharge amount than to increasing it

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Phytoremediation is one of the cleanup methods of polluted soil that is possible accumulation of heavy metals in plant tissues, exclusion of these elements from contaminated soil. Therefore, to achievement the objective, this research was done in pot culture using completely randomized design at the University of Birjand in 2011. Two species Spinacia oleracea and Lepidium sativum were used to remove or reduce the concentration of Cadmium (Cd) and Chromium (Cr). In this study, different levels of Cadmium (CdCl2) concentrations including 5, 50, 100 mg kg-1 and also chromium (CrCl3) concentrations 50, 100, 150 mg kg-1 were used respectively and control as well for each species with three replications. Results indicated that the Cd and Cr concentration in shoot of Spinacia oleracea and Lepidium sativum significantly affected by their concentration in soil (p<0/01). Results revealed that increasing of Cd and Cr concentrations in soil, showed an increase concentration of both metal in shoot of Spinacia oleracea. increasing of Cd concentrations in soil, showed an increase concentration of it in shoot of Lepidium sativum but the concentration of Cr was less. Also, comparison of cadmium and chromium concentrations in shoot of Spinacia oleracea and Lepidium sativum showed that two species showed same behavior of Cd and different behavior Cr concentration. So the analysis of data showed that both of species are appropriate for absorption of Cd and Cr and phytoremediation technology as well. It can be concluded that in high soil Cr concentration for phytoremediation Lepidium sativum is not appropriate.

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Reduction of quality and soil productivity due to organic carbon losses is one of the most important consequences of land use changes, that creates irreparable effects on the soil. To evaluate the land use effect on the amount of soil organic carbon in Vertisols, Sartip Abad series with extent of 1850 hectare in south of Bilehvar area in Kermanshah province was studied by using the completely randomized block design in factorial experiment with 10 repeats in farmland and grassland, some soil physical and chemical properties in two Lands compared with each other. The results showed that the soil organic carbon in surface horizons of grassland has been more than farmland and accordingly increase the amount of sequestrated carbon in grassland. No significant differences were found in the amount of soil organic carbon in lower horizons of two lands. Due to land use change from grassland to farmland, noticeably increase in Bulk density, Nitrogen, Acidity, soil Electrical Conductivity and decrease the organic carbon percent and the soil organic material. Pedutorbation, clay amount (higher of 50%), numerous small subsoil, and stable structure are the important factors in saving the organic carbon of vertisols that can reduce the effects of land use changes on organic carbon amount. Generally, it can be conclude that: the land use changes not only can create the severe damage on soil physical and chemical properties but with the carbon losses and more release of greenhouse gases exacerbate the pollution of environment which endangers the life in a earth planet.

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Fine-grained materials of Clayey Loess deposits of Gorgan region were mixed with sand dune in the lab with various rations and their shear behavior was measured and evaluated by direct shear test. The result of the study showed that the increase of fine-grained clay in sand dune was directly related to the adhesion force and inversely to the internal friction angle. The increase or reduction in shear strength was affected by the fine-grain percentage. Dry condition and saturation of the test and sand dune had a less influence on shear parameters but in the mixed samples in dry condition and saturation, shear parameters revealed a considerable difference. The results of this study can be used in sand stabilization, erosion prevention, slope stability, embankment construction, compaction increase, and environmental pollution, and dust and water channels avoidance.

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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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Soil aggregate stability is considered as a key indicator of soil quality and health assessments in rangelands. Many factors and properties such as soil texture, organic carbon, calcium carbonate, sodium adsorption ratio, and electrical conductivity might affect soil aggregate stability. The effects of these factors on aggregate stability of 71 soil samples collected from 4 rangeland sites (2 in semi-arid and 2 in arid lands) in Isfahan province were investigated. Aggregate stability was measured using the wet-sieving method. To optimize the trial conditions for the investigated soils, three shaking times (5, 10 and 15 minutes) were used to impose different hydromechanical stresses on the aggregates of ten soils selected out of the studied soils. The structural stability was assessed using mean weight diameter (MWD) and geometric mean diameter (GMD) of the water-stable aggregates. Significant differences of MWD were observed between the shaking times. The 10-min shaking was selected as best for structural stability assessment in the studied regions because it resulted in better differentiation of soils on the basis of structural stability. Among the intrinsic properties, soil organic carbon content had the most important role in aggregate stability in all zones. However, electrical conductivity (in addition to organic carbon content) had an important role in aggregate stability in the arid rangelands. Log-normal distribution and GMD could represent better the aggregate size distribution when compared with normal distribution and MWD in the studied regions. Overall, wet-sieving method with shaking time of 10 min is suggested to assess the soil structural stability in rangelands of Isfahan province. Therefore, soil aggregate stability and the factors affecting this vital indicator can be used efficiently for assessing and monitoring management effectiveness and rangeland functionality trend.

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The objective of the current research was to prioritize effective factors in landslide occurrence and its susceptibility zonation using Shannon’s entropy index in North of Tehran metropolitan. To this end, 528 landslide locations were identified using satellite images such as Geoeye (2011-2012), SPOT-5 (2010), and field surveys, and then landslide inventory map was created for the study area in ArcGIS environment. Data layers such as slope degree, slope aspect, plan curvature, altitude, lithology, land use, distance of road, distance of fault, distance of drainage, drainage density, road density, sediment transport index (STI), stream power index (SPI), topographic wetness index (TWI), normalized difference vegetation index (NDVI), surface area ratio (SAR) and topographic position index (TPI) were created and the mentioned maps were digitized in GIS environment. Prioritization of effective factors by Shannon’s entropy index showed that the layers such as land use, lithology, slope degree, stream power index, and NDVI had the most effect on landslide occurrence. However, factors of topographic position index and plan curvature had the least effect. Also, landslide susceptibility zoning by the mentioned model and its accuracy assessment using relative operating characteristics (ROC) curve and 30 percent of landslide locations showed an accuracy of 82.83% with a standard error of 0.0233 in the study area.

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Hydrologic drought which usually affects wide regions can be studied through Low flow index. In this study, to predict hydrologic drought in North Karoon watershed, 14 stations with suitable and long enough duration data were recorded in the 1387-88 water year. Then 13 physiographic and climatic characteristics of the chosen stations were used to perform homogeneity test for cluster analysis. 7 day low flow series were calculated in each station and according to chi-square and Kolomogragh smirnov tests and parameter, 2 parameter gamma distribution was selected as the best regional distribution for this region. Therefore, a seven day low flow index was estimated using FREQ for 5,10,20,50,100 return periods. Regional analysis was performed using a multiple regression method. Moreover, flow duration curves were delineated to obtain Q95 index. Then, zoning maps for Q95، Q7,2 ،Q7,10, Q7,100 were prepared. The results of regional analysis indicated that the averages of height and slope were the two most effective parameters in low flow in this watershed. The investigation of zoning maps showed that southeastern part of this watershed experiences severe droughts compared with other parts.

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In order to investigate the effects of furrow irrigation and amount of irrigation water on yield and water use efficiency of corn, an experiment was conducted as a split plot based on a randomized complete block design with three replications for a period of two years at Agriculture Center of Mazandaran. Treatments included three levels of 100, 80 and 60 percent water requirement as the main treatments, and three irrigation methods included fixed every-other- furrow, alternative every-other- furrow and every-furrow irrigation as the subsidiary treatments. Statistical analysis of the results of two years' data showed that treatment with 100% water requirement with every-furrow irrigation and treatment with 60% irrigation water requirement with fixed every-other-furrow had the highest and lowest yield, respectively. The highest water use efficiency was in 60 percent irrigation water requirement with a fixed every-other- furrow treatment and the lowest water use efficiency was related to the treatment with 100 percent irrigation water requirement with alternative every-other- furrow. The value of ky was obtained 0.8 for the total growth stage.

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CEC of the soil is the exchange sites of organic and inorganic soil colloids. Modeling and Estimation of CEC is a useful indicator for fertility. The new alternative approaches for estimating CEC are indirect methods based on intelligent models. In this research in order to estimate CEC, 485 soil samples were prepared from two regions, chaparsar (Mazandaran in northern Iran) and Bostanabad (North of West Azarbaijan, Iran).In this paper introduces the application of genetic programming. Input parameters that are percent Clay, Organic Carbon and Silt, evaluate using genetic programming, neural network and Neural Inference Systems-Fuzzy models. The results indicate a good ability to intelligent models for CEC Estimation According to indices used in this study. Genetic programming model with a root mean square error of 1.78 and coefficient of determination 0.95 compared to other models have been more efficient and is able to provide satisfactory results, Also are the explicit solutions that reflect the relationship between input an output variable, was presented based on genetic programming. This preferred the genetic programming model adds the other models. Stepwise regression analysis to determine the contribution of each of the parameters indicated in the CEC that organic materials having Most coefficient of variation of 84% is justified CEC and clay and silt, respectively, with a correlation coefficient of 10% and 6% respectively.

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Terraces are old geomorphic surfaces that are not related to present streams and are best places to study the effect of time on soil formation (chronosequence). This research was carried out to study some physico-chemical parameters especially different forms of iron as soil development indices on terraces of Karaj River in Hassan-Abad, southern Tehran. To determine soil development indices in 4 profiles occurring on 4 terraces, some physical and chemical properties were measured and free iron(Fed), aluminum(Ald), silica(Sid) and manganese(Mnd), amorphous Fe(Feo), Al(Alo), Si(Sio), Mn(Mno) and Fe, Al, Si-humus complexes were extracted. Results showed that clay, fine clay/total clay, CEC, the color redness and leaching of calcium carbonate increase toward higher terraces. Contents of Fed, Ald and Sid increases from lower terrace (T1) to the higher terrace (T4). Fed-Feo and Feo/Fed as the most important indices of soil development were enhanced and reduced from lower terrace (T1) to higher terrace (T4) soils, respectively, which indicate an increase in iron oxides crystalinity and soil profile development. Contents of Fed-Feo in the B horizons from T1 to T4 were 600, 800, 1000, and 1400 mg/kg soil, respectively. Calculation of Ferrihydrate and Fe-hydr(oxide) such as goethite and hematite showed that the amounts of these components were increased from T1 to T4 terraces confirming the variation of (Fed-Feo), (Feo/Fed) and (Feo-Fep) indices.