JWSS - Journal of Water and Soil Science

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Due to the important role of climatic parameters such as radiation, temperature, precipitation and evaporation rate in water resources management, this study employed time series modeling to forecast climatic parameters. After normality test of the parameters, nonparametric Mann-Kendall test was used in order to do trend analysis of data at P-value<0.05. Relative humidity and evaporation (with significant trend, -0.348 and -0.42 cm, respectively), as well as air temperature, wind speed, and sunshine were selected for time series modeling. Considering the Autocorrelation function (ACF) and Partial Autocorrelation function (PACF) and trend of data, appropriate models were fitted. The significance of the parameters of the selected models was examined by SE and t statistics, and both stationarity and invertibility conditions of Autoregressive (AR) and Moving average (MA) were also tested. Then, model calibration was carried out using Kolmogorov-Smirnov, Anderson- Darling and Rayan-Joiner. The selected ARIMA models are ARIMA(0,0,11)*(0,0,1), ARIMA(2,0,4)*(1,1,0), ARIMA(4,0,0)*(0,1,1), ARIMA (1,0,1)*(0,1,1), ARIMA (1,0,0)*(0,1,1) for relative humidity, evaporation, air temperature, wind speed and sunshine, respectively. The fitted models were then used to forecast the parameters. Finally, trend analysis of forecasted data was done in order to investigate the climate change. This study emphasizes efficiency of time series modeling in water resources studies in order to forecast climatic parameters.

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Iron deficiency is most widespread among plant nutrients. Nowadays, different materials such as inorganic salts, organic chelates, soil acidifying materials and industrial wastes are used to correct iron deficiency. Slag and convertor sludge of steel factories are among the industrials wastes for this purpose. These materials contain considerable amount of iron produced in large quantities every year. Application of slag and convertor sludge to soil may affect bioavailability and chemical forms of iron in soil. Sequential chemical extraction technique has been widely used to examine these chemical forms, and thus to better understand the processes that influence element availability. It was, therefore, the objective of this study to investigate the application effect of slag and convertor sludge of Esfahan Steel Mill on the chemical forms of iron, distribution of these forms and bioavailability of iron in surface (0-20cm) and subsurface (20-45cm) soil of three research fields. The results showed that more than 99% of the applied Fe occurred in residual, Fe oxide and hydroxide and free forms. Application of slag and convertor sludge for three consecutive years increased chemical forms and DTPA extractable iron in surface and subsurface soil of three fields.

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Silver toxicity and its fate in the environment are currently being debated and are important as challenging research topics. Even though there are several studies on its total content in soils, fractionation of Ag especially in calcareous soils has not been investigated. Therefore, to provide fundamental information on the chemical behavior of Ag in calcareous and noncalcareous soils, we studied 8-step chemical fractions of Ag (i.e., EXCH, CARB, Me-Org, re-MeOx, H2O2-Org, am-MeOx, cr-FeOx, and RES) after 30 and 60 days of incubation in soils amended with Ag (0 and 15 mg kg-1), sewage sludge (0 and 20 t ha-1) and EDTA (0 and 0.5%). Experimental results showed that redistribution of Ag in spiked noncalcareous soils was EXCH (34%), H2O2-Org (33%) and RES (17%). In calcareous soils, after 30 days, EXCH- and RES-Ag increased but at the end of 60 days H2O2-Org-Ag increased. Based on our data, we could conclude that addition of Ag results in an increase of Ag mobility in soils but incubation and sewage sludge may have adverse effect on its mobility. In contrast to noncalcareous soil, EDTA in calcareous soil resulted in higher Ag mobility. This may have environmental implications in Ag polluted calcareous soils.

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Mountainous landscapes in Central Zagros are mainly used as grazing rangelands to feed animals and are heavily degraded. Overgrazing may impose a negative effect on rangeland productivity and sustainability through significant changes in soil properties. Soil nitrogen (N) mineralization is one of the key biological processes that might be affected by biotic and abiotic factors including range grazing regime or intensity. The primary objective of this study was to assess the effects of rangeland management (grazing and ungrazing regimes) on soil N mineralization in natural rangelands of Chaharmahal VA Bakhtiyari province. Three range management regimes including a) long-term ungrazed, b) controlled grazed and c) freely- (over)-grazed plots in a close vicinity were selected in three regions consisting of SabzKouh (protected from grazing for 18 years), Boroujen (protected from grazing for 23 years) and Sheida (protected from grazing for 2 years), and soil samples were collected from 0-15 cm depth for some physical and chemical properties. Soil N mineralization was measured under standard laboratory conditions. At SabzKouh, the effect of range management on the cumulative N mineralization and the proportion of N mineralized (%) was significant (P<0.05) and ungrazing regime resulted in 89% and 96% increases in soil N mineralization in ungrazed rangelands compared with controlled grazed and freely- grazed rangelands, respectively. Similarly, soil N mineralization was significantly greater (P<0.05) in ungrazed rangelands (3.3- to 3.5-folds) than in controlled grazed and freely-grazed rangelands at Boroujen site. However, at Sheida site with short-term ungrazing period and cropping history there were no significant and considerable differences in soil N mineralization among the three grazing regimes. Briefly, degraded rangelands at SabzKouh and Boroujen sites seem to recover rather quickly from long-term overgrazing with a proper grazing management, while rangeland ecosystems at Sheida site need a much longer period for steady-state conditions and for improvements in soil quality and fertility after long-term soil degradation and disturbance.

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Precision farming aims to optimize field-level management by providing information on production rate, crop needs, nutrients, pest/disease control, environmental contamination, timing of field practices, soil organic matter and irrigation. Remote sensing and GIS have made huge impacts on agricultural industry by monitoring and managing agricultural lands. Using vegetation indices have been widely used for quantifying net annual production on different scales. The aim of this study was to find a rapid method with acceptable precision for the identification and classification of agricultural lands under cultivation (wheat and barley, alfalfa and potatoes). We used multi-temporal AWiFS data and applied Boolean logic and unsupervised classification. Results indicated that Boolean logic approach had a higher accuracy and precision in comparison to unsupervised classification, although it is more complicated and time consuming.

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Vegetation is the most important factor in sustainable and dynamic equilibrium of natural ecosystems. Considering the relation between environmental factors and vegetation is an essential step in order to identify the effective factors in the habitats. The purpose of this study was to evaluate the relations between vegetation and soil characteristics in rangelands of Ferydounshahr (Sardab-Sibak watershed). The flora and vegetation types were studied using Physionomic-floristic method in the field and eight vegetation types were identified. Vegetation was sampled by Systematic–randomized method in 1× 2 m plots. The canopy cover and species composition percentage were estimated in each plot. After digging a soil profile in vegetation types, the physical and chemical factors were measured. The influences of edaphic factors on vegetation were analyzed using RDA ordination technique. Results showed that based on soil characteristics the eight vegetation types can be classified in to three main range habitats including, Ferula ovina, Astragalus adscendens and Astragalus brachycalyx. The most important factors which cause the separation in these three habitat ranges were clay percentage, organic matter, soil depth, CaCO3, pavement and barren soil.

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Puddling is the most common method of land preparation for lowland rice cultivation. The purpose of this study was to assess the influence of various intensities of puddling on percolation rate, water retention by soil and the amount of water used for different puddling intensities in three dominant soil textures of paddy fields in Guilan province. Undisturbed soil samples were taken from 3 different soils including silty clay, clay loam and loam, with 3 replications. The soil samples were puddled by a laboratory apparatus with different intensities. The results showed that the low puddling intensity treatment caused a 29.3, 32.4 and 36% reduction of percolation rate in silty clay, silty loam and loam textures, respectively. Increasing puddling intensity from low to medium reduced percolation rate significantly, but high intensity was not effective. Soil moisture characteristic curves of all three soils showed that water retention was increased by puddling treatments. Water retention in silty clay was higher than the other two soils. The high intensity treatment needed more water than low intensity for puddling. Increasing puddling intensity from medium intensity to high intensity caused 15.4, 14.1 and 16.3% increase in the amount of water required for puddling in silty clay, silty loam and loam textures, respectively. Generally, in all the three studied soil textures, the amount of water used for high-intensity puddling was more than medium-intensity puddling, while it had no significant effect on water percolation rate and soil water retention.

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Soil saturated hydraulic conductivity (k) and effective porosity (f) are the most important parameters to simulate the processes associated with irrigation, drainage, hydrology, leaching and other agricultural and hydrological processes. Present methods to measure these parameters are often difficult, time consuming and costly. Therefore, a method which provides more accurate estimates of these parameters is essential and is considered inevitable. The purpose of this study was simultaneous estimation of k and f using approach inverse problem. In this study, analytical drainage model of Glover-Dam was used to simulate the inverse problem method. Also, genetic algorithm was used as an optimization technique for determination of optimal values of k and f. In order to measure the data required for calibration and evaluation of the proposed inverse problem model, a physical model was designed and constructed in the laboratory. The results showed that the proposed method is good for simultaneosly estimating simultaneous soil k and f. Also with variable f assumption, the prediction error of water table around the drainage was reduced significantly.

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In Guilan province, Sefidrud River, as the main source of irrigating rice in Guilan province, has been subjected to increasing salinity and a decreasing discharge because of decreasing in the volume of sefidrud dam, diverting water upstream and entering different sewages into the river. This research tries to determine optimum irrigation depth and intermittent periods in proportion to salinity resistance at different growth stages using optimization- simulation model. After calibration, Agro-hydrological SWAP model was used to simulate different growth stages of rice. Optimization results were obtained for managing fresh and saline intermittent water, 8-day intermittent period, for salinity of 0.747 dS/m in sensitive maturity stage and salinity of 3.36 dS/m in resistant vegetative, tiller and harvest growth stages. It is suggested that the depth of irrigation water be 1, 3, 3 and 5 cm for vegetative, tiller, maturity and harvest stages, respectively. Comparing managements of irrigation and saline based on the resistance of different growth stages to salinity and exploitation of irrigating water with a constant salinity during growth periods of the plant showed that irrigation management based on resistance of different growth periods of the plant to salinity causes rice yield to be improved by 23percent.

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Cow manure and sewage sludge add heavy metals to soil. Organic and inorganic fractions in these compounds can immobilize heavy metals such as lead (Pb) and affect their bio-availability. This investigation was conducted to compare the effects of organic and inorganic fractions of sewage sludge and cow manure on distribution of lead chemical forms in soil as a completely randomized design. Treatments consisted of application of 10% (w/w) enriched sewage sludge and cow manure (6 g Pb kg-1 organic amendments). Another treatment was also used in which soil Pb concentration was increased to 600 mg kg-1 soil using Pb(NO3)2 salt. To compare the effects of organic and inorganic fractions, organic carbon, iron oxide and easily reducible iron and manganese were removed from cow manure and sewage sludge, and were added to the soil by 10% (w/w). The samples were incubated at 23-25ºC for 111 days and their moisture was maintained at 80% water field capacity. More than 50% Pb in Pb(NO3)2 treatment was in exchangeable fraction, while for cow manure and sewage sludge treatments more than 40% Pb was found to be in oxide fraction. Application of cow manure and sewage sludge increased the Pb in oxide fraction by 14.8 and 17.5%, respectively. Removing organic carbon fraction of cow manure and sewage sludge increased the Pb bound to residual fraction by 12% and 14% respectively. Removing iron oxide fraction of sewage sludge and cow manure decreased the Pb bound to oxide fraction by 8% and 13%, respectively. Removing easily reducible iron and manganese decreased the oxide fraction of Pb by 16% and 14%, respectively. It is concluded that, despite relatively high amounts of organic carbon in the sludge and manure, inorganic fractions of these materials have more significant effects on availability of Pb in soil.

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This study was conducted to study and compare the effects of different tillage systems on soil physical properties and wheat yield in dryland conditions. The experiment was carried out in Maragheh Dryland Research Station with 5 treatments and 4 replications based on RCBD for 3 years (2001-2003). The results showed that difference between the treatments in terms of wheat yield was significant, and stubble chopping and chisel plow tillage in fall + sweep in spring + seed drill planting had the maximum yield (i.e. 1452 kg/ha), lower value for yield (1.077kg/ha) blonged to T1 treatment. Also the results showed that spike/plant and spike length were the main characters in yield increase. For the soil bulk density and water content, the difference between treatments was significant and in planting and flowering stages stubble chopping and chisel plow in fall + sweep in spring + planting by seed drill had the highest soil water content and the lowest bulk density

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In this study, a completely randomized experiment was designed with four irrigation treatments and three replicates. The irrigation programs were raw wastewater, treated wastewater, a combination of 50% raw wastewater and 50% potable water and a combination of 50% treated wastewater and 50% potable water. The experiments were run within a greenhouse. The lysimeters were built up on September 2009 and they were filled with two layers of soil. The upper (0-30 cm in depth) and lower (30-70 cm in depth) layers were sandy loam and sandy clay loam, respectively. A total of eight watering programs with an interval of elevens-day were applied. After each irrigation program, intake wastewater and drainage water of each Lysimeter was sampled in order to analyse the transport of heavy metals (Cu, Zn, Fe and Mn, Ni, Cd and Pb). Results showed that the effect of water quality was significant on percentage of transport of heavy metals. The lowest transport percentage of heavy metals belonged to raw wastewater treatment. Also, the highest percentage of transport of Cu, Zn, Fe, Ni and Pb belonged to the combination of 50% raw wastewater and 50% potable water. In most cases, we observed that the transport percentage of these elements increased by continuing the irrigation

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Studies on the soils of western Golestan province show that regardless of increased rain and presence of clay minerals with high cation exchange capacity, potassium extractable with ammonium acetate is low. In order to find the reason for this low amount of available K, clay minerals and micromorphology of the soil porosity were studied. Twenty disturbed and undisturbed samples from each horizon were taken for physicochemical properties, mineralogy and micromorphological studies. Four selected profiles included Gypsic Aquisalids, Typic Endoaquepts, Typic Calcixerolls and Typic Hapludalfs. The results showed that in addition to the clay content and type of clay minerals in soils that can affect soil available K (Kava.), it seems soil porosity can also affect Kava. mainly through their effects on extension of roots, water and nutrients transmission. Favorable content of clay and dominance of smectites in Mollisols and also higher porosity and dominance of channel porosities caused the presence of higher Kava, in these soils. presence of HIS. poor soil drainage, reduction of Fe3+ in smectite crystal lattice in Inceptisols, and also less amount of porosities caused the presence of higher potassium fixation and reduction of Kava. in these soils.

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Potato is one of the most important tuberous crops. To achieve optimum yield in potato, suitable brand and sufficient and balanced soil nutrients are necessary. In order to study the effects of Zinc, Manganese and Copper on potato yield and leaf and tuber concentrations of Phosphorus and Iron, a factorial pot experiment with 32 treatments was conducted in greenhouse of Soil Science Department, Zanjan University, using a completely randomized design and three replications. The study factors were four levels of Zinc(Zn0: 1.14, Zn1: 5, Zn2: 10 and Zn3: 15 mg/kg soil), four levels of Manganese(Mn0: 1.4, Mn1: 5, Mn3: 10 and Mn4: 20 mg/kg soil) and two levels of Copper (Cu0: 0.22 and Cu1: 2 mg/kg soil) which were applied to the soils of planting pots. The results showed that potato yield increased as the soil concentrations of Zinc, Manganese and copper increased to certain levels Soil application of zinc and manganese fertilizers significantly decreased leaf and tuber concentrations of Phosphorus and Iron. Soil application of copper decreased Iron concentration of leaf but not Phosphorus. The highest potato yield was obtained from the treatment of 15, 10 and 2 mg zinc, manganese and copper per kg of soil, respectively.

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Magnetic susceptibility measurement is a simple and quick technique for characterizing soils and sediments and describing soil-forming processes. The interpretation of soil magnetic susceptibility data needs sufficient knowledge about the factors affecting this parameter. To identify the effects of parent material, gypsum and calcium carbonate equivalent, 42 samples were taken from horizons of soils developed on loessial, alluvial, granitic and marly materials in southern Mashhad. Gypsum and carbonates of soil samples were removed by successive washing with distilled water and diluted HCl, respectively. Magnetic susceptibility of bulk samples (lfbulk), gypsum free samples (lfGf), gypsum and carbonates free samples (lfGCf) and gypsum, carbonates and sand free samples (lfGCSf) was measured. The results revealed a strong 1:1 correlation between the measured and calculated lfGf and lfGCf. Despite the high amounts of gypsum and carbonates in soils developed on marls, their lfbulk was much more than that of the other soils and reached up to 121.8×10-8m3 kg-1. In contrast, the lfbulk values of saprolitic granite were less than 10.4×10-8m3 kg-1. The lfbulk values of loessial and alluvial soils were less than those of marly soils but higher than those of soils developed on saprolitic granite. lfbulk values were negatively correlated with the amount of sand. However, reduction in magnetic susceptibility values of marly soils after removing sand reflects the different nature of this soil. The correlation between lfbulk and amount of silt and clay is positive, but the magnetic susceptibility values are more sensitive to clay percentage, indicating the more important contribution of clay to magnetic susceptibility values. The results of this study highlight the role of parent materials, gypsum and carbonates in the soil magnetic susceptibility values that should be considered.

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In this study the effects of irrigation with raw or diluted municipal effluents along with foliar micro-nutrients fertilizer spray were examined on the growth, yield and mineral nutrient in foxtail millet plants. The experimental design was a split-plot with three irrigation sources (namely raw sewage, 50% diluted sewage and well water) as main-treatment and four combinations of Mn and Zn foliar spraying as sub-treatments, which were applied with three replications. The experiment was conducted at the Zabol University research farm during 2009. The applied municipal effluents contained higher levels of macro and micro-nutrients than the well water. The experimental results indicated that irrigation of plants by raw or diluted sewage improved the measured growth parameters and productivity of foxtail millet plants. In addition macro and micro-nutrients concentrations were improved. These improvements were attributed to the presence of high levels of essential nutrients such as nitrogen, phosphorus, and organic matters in wastewater. Manganese and Zn supplied through sewage water alone were not able to raise the productivity of millet to the level obtained through fertilizers at the recommended level, which indicated that additional nutrients through fertilizers are required to obtain higher productivity of millet under sewage farming. Despite the differences in nutrients concentration among different irrigation water sources, the micro-nutrients foliar spray did not affect concentration of macro and micro-nutrients in foxtail millet plant. Overall, the results suggest that municipal sewage could be efficiently utilized as an important source of water and nutrients in growing foxtail millet Sewage water irrigation did not have any appreciable harmful effect on crop productivity.

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Digital soil mapping includes soils, spatial prediction and their properties based on the relationship with covariates. This study was designed for digital soil mapping using binary logistic regression and boosted regression tree in Zarand region of Kerman. A stratified sampling scheme was adopted for the 90,000 ha area based on which, 123 soil profiles were described. In both approaches, the occurrence of relevant diagnostic horizons was first mapped, and subsequently, various maps were combined for a pixel-wise classification by combining the presence or absence of diagnostic horizons. Covariates included a geomorphology map, terrain attributes and remote sensing indices. Among the predictors, geomorphology map was identified as an important tool for digital soil mapping approaches as it helped increase the prediction accuracy. After geomorphic surfaces, the terrain attributes were identified as the most effective auxiliary parameters in predicting the diagnostic horizons. The methods predicted high probability of salic horizon in playa landform, gypsic horizon in gypsiferous hills and calcic horizon in alluvial fans. Both models predicted Calcigypsids with very low reliability and accuracy, while prediction of Haplosalids and Haplogypsids was carried out with high accuracy.

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Crisis of quality and quantity of water resources is one of the most important problems in arid and semi-arid areas such as Iran. Wastewater treatment and reuse as a potential source of water can not only compensate for the water scarcity but also can prevent the hazardous pollutants from entering the groundwater and surface water resources. There are various methods to improve water quality, among which method of filtration is an effective and efficient method to remove elements. The most important issue for filter system is the selection of adsorbent materials. In this work, the tire chips were used as adsorbent. Column adsorption tests in a pilot system were conducted in two distinct steps using two types of water, including salt water and industrial effluents. Each test was conducted as a factorial experiment with three factors based on a completely randomized design with three replications. Three factors were studied including particle size (2-5 mm and 3-5 cm), filter thickness (10, 30 and 50 cm) and sorbent contact time with solution. The results showed that adsorption rate increased by increasing the thickness of the filter and sorbent contact time with solution. The best performance of reducing the salinity was observed in the treatment with 50 centimeter thickness and 24 contact hours. The salinity of this treatment was reduced by 20.3 percent (in the test with salt water) and 11.2 percent (in the test with industrial effluents). This filter reduced the heavy metals of lead, zinc and manganese up to 99, 72.1 and 41.4 percent, respectively. Also, the performance of millimeter and centimeter particles did not show a significant difference. Generally, the tire chips showed a proper performance to improve the water quality especially for industrial wastewater.

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Iron and manganese oxides as well as hydroxide minerals are among active constituents in soils because they are sensitive to environmental changes and often move frequently along soil profile. Therefore, their chemical forms content and their ratios are used as a soil developmental criterion. The present study was conducted in order to evaluate the effects of topography and drainage conditions on chemical forms of Fe and Mn along a soil catena in Dasht-e- Roum plain, in Kohgilouye Province. According to the results, maximum pedogenic Fe and Mn (Fed and Mnd) was found in more stable geomorphic surfaces. Higher values of Fed and Mnd were mostly observed in surface horizons compared to soil depth. Aquic soils exhibited higher contents of poorly crystalline Fe and Mn (Feo and Mno) and higher contents of Fed and Mnd. A significant correlation between clay content and Feo, Mno, Fet and Mnt contents was found. In addition, aquic condition increased Feo/Fed, Mno/Mnd and Mnd/Fed, 3.1, 4.3 and 1.9 times respectively but decreased the Fe crystallinity index 2.6 times. Aquic soils seem to have more favorable conditions for the formation of pedogenic Mn compared to pedogenic Fe, hence higher content of Mnd/Fed was observed in these soils

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Stage – discharge relationship is mainly developed from measured data in any hydrometry station. Measured data usually obtain in low to medium flow discharge, because in most cases it is very difficult to measure the flow discharge during flood. Therefore, the stage–discharge is extrapolated beyond the measured data to compute the flood which may estimate low or higher value. This is because during the high flow, the bed form is developed which causes the flow resistance to change. In order to establish a better stage – discharge relation, it is important to apply methods which consider the bed form resistance. In this study an attempt has been made to determine the best method for developing such relationship. To reach the goal, the required data such as river cross section, discharge and related stage and bed material gradation from Ghorbaghestan hydrometry station were measured for two years. Then a computer program was developed. Using this program and applying the measured data, the stage – discharge relationships were computed by five different methods. From the statistical comparison of the results of these methods with measured data, it was found that Shen, Brownlie, Engelund and White’s method overestimate the flow discharge. The best method was found to be the Einstein – Barbarossa’s method that provided the minimum absolute mean errors 0.31 and 1.468 m3/s and minimum root mean square error 0.112 and 0.466 m3/s for the two study years, respectively