Journal of Water and Soil
Year:2009 | Volume:23 | Issue:3|Papers Count:21

In order to estimate the reference evapotranspiration different equation is used. Validity of each method depends upon the climate and the parameters which are used in these equations. Therefore it is necessary to calibrate these methods for any specific area and for any desired frequency. In this study common temperature and radiation based methods were used for calculating crop evapotranspiration and the results were compared with standard method of estimating reference evapotranspiration. The results showed that Jensen-Haise(J-H) method overestimate ET compare to Hargreaves-Samany(H-S) method. The difference is more in 3 days period of irrigation than 5 days period. Also for wheat and barely H-S method estimates higher value of ETc compared with J-H method. However, J-H method overestimates ETc for cotton and rice. By increasing the probability level, the difference between calculated ETc by J-H and H-S decreased significantly.

Edible white button mushroom is a secondary decomposer and the activity of other micro-organisms is necessary to decompose the raw compounds for its growth. Actinomycetes bacteria due to their ability to decompose the compound molecules such as cellulose, lingo-cellulose and lignin, play an important role in the composting process for the mushroom. Bacterial biomass of actinomycetes contains a high rate of nitrogen and minerals, necessary for growth of the mushroom. To investigate the effects of actinomycetes on growth of mushroom mycelia, isolates of the genus of Streptomyces، Saccharomonospora, Thermomonospora, Nocardioides, Saccharopolyspora, Microbispora, Glycomyces were used for inoculating of sterile compost and preparing bacterial biomass. The result showed that inoculating of compost with actinomycetes could have a significant effect on the growth of mushroom mycelia, compared to the control. Isolates belonging to the genus Streptomyces supported a higher growth of the mushroom mycelia.

In recent years, many researchers have attempted to estimate the soil hydraulic functions (e.g. soil moisture characteristics curve, and hydraulic conductivity function) using particle-size distribution (PSD) curve. In these studies, an accurate mathematical representation of PSD is required for fitting the observed data. So far, some mathematical models were developed with different limitations. The goodness of fit is directly related to the number of the model parameters. However, estimating the parameters for higher-parameter models which have no mathematical or physical significance is a problem. Among the current models, 2-parameter Log-normal distribution model with mathematical significant parameters has been considered as a basis for many studies. In this study, it is indicated that the 2-parameter Log-normal distribution model can not be very accurate for representation of the PSD for all of soil textural classes. As an alternative, 2-parameter Gamma distribution model is proposed for more accurate representation of the PSD that its two parameters also are mathematical significant and readily computable. These two models have been compared in fitting the observed PSD data of 461 soil samples from UNSODA soil database. Gamma distribution model indicated a pronounced improvement in representation of the PSD. Based on Coefficient of determination (R2), in 362 samples and based on RMSE, in 323 samples, Gamma distribution model showed a better representation of the PSD than Log-normal. To evaluate the significance of the difference between two models, a t-test was performed. The results showed that, at confidence level of 1%, the R2-values of the Gamma model are significantly greater than those of Log-normal model. Also, at confidence level of 5%, a significant difference between the RMSE-values of two models was shown. Therefore, 2-parameter Gamma distribution model is judged to be better than 2-parameter Log-normal model for representation of PSD.

The use of plants for remediation of heavy metals contaminated soils is an economical, cheap and effective strategy. This research was conducted in order to study the effect of potassium chloride on cadmium uptake and enhancement of it's phytoremediation by canola (Brassica napus L.) and sunflower (Helianthus annuus L.) in a cadmium polluted soil from Angoran in Zanjan province. In a randomized complete block design (RCBD), with three replications, four levels of potassium (0(control), 50,100 and 200 mg K2O per kilogram of soil as KCl) was performed and Azargoal hybrid variety of sunflower and Double Zero variety of spring canola separately were planted in pot. The ANOVA results showed that application of KCl treatments have significantly effects (P<0.01) on dry matter production of root and shoot, Cd concentration, uptake and translocation factor (TF). In this study the highest amount of Cd uptake by sunflower (84.57mgpot-1) and canola (64/10mgpot-1) was obtained by application of 200 mg K2O per kg of soil. The Cd translocation factor of Canola (2.5) was higher than sunflower (1.6). Therefore, based on pot experiment and lab analysis results, these crops are suitable for Cd phytoextraction in phytoremediation technology and KCl application can improve phytoremediation efficiency of cadmium polluted soil. More research under field condition can be useful and is recommended.

Arsenic (As) contamination of soils is a global problem. Legumes are often used in remediation of contaminated sites because of their capacity to fix nitrogen. In the present study, the effects of inoculation of bean (by Rhizobium leguminosarum bv. phaseoli) on plant uptake and tolerance to arsenic were investigated. An experiment with a factorial arrangement, two levels of inoculation (with and without inoculation) and five levels of arsenic concentrations (0, 2.5, 5, 7.5 and 10 mM) in completely randomized design with three replications was carried out in a sand culture system in a green house condition. The results showed that the dried shoot weight was increased significantly by inoculation treatments. However, dried root weight and plant height were not affected by inoculation. Dried shoot weight was significantly decreased by increasing arsenic concentrations. The least dried shoot weight was observed in 5, 7.5 and 10mM of arsenic. The response of dry root weight and plant height to arsenic concentrations was similar to dried shoot weight. The least nodule number was observed in 5mM arsenic treatment and nodule number in other treatments was not affected by arsenic concentration. Arsenic concentration in shoot increased by Rhizobium leguminosarum bv. phaseoli inoculation. The concentration of arsenic in bean shoot increased by increasing arsenic concentrations in medium. However the highest concentration of arsenic in root and the least nodule number were observed in 5mM arsenic.

Population increase, limitation of water resources, and increasing volume of municipal wastewater, has caused the necessity of wastewater reuse. Application of wastewater on soils seems to be the most economical method of its disposal and by percolating wastewater through the soil; its chemical quality is improved. For this purpose, a greenhouse experiment was carried out with polyethylene columns (150 cm in length and 11 cm in diameter) during 7 periods of 15 days in Ferdowsi University of Mashhad. A statistical completely randomized design was used. Raw and treated wastewaters from Parkandabad Treatment Plant were applied intermittent in columns filled with sandy loam soil. At The end of experiment, sampled of leachate were analyzed for parameters sach as pH, salinity, SAR, NO3-N, PO4-P, TOC, and two heavy metals of Cd and Ni. The results showed that the mean values of each of the above mentioned parameters, with the exception of pH, were lower in the leachate compared to the wastewaters entering the soil. However, with continuous application of wastewaters increase in the amount of these components was observed. Considering the effect of type of wastewater on values of above parameters, mean of pH value was significantly lower for raw wastewater (7.65) in the leachate as compared to the treated wastewater (7.71). NO3-N, PO4-P and Ni showed an opposite trend. The mean values of these parameters leached out from soil columns were 21.96, 0.055 and 0.015 (mg/l) for raw wastewater and 20.48, 0.024 and 0.012 (mg/l) for treated wastewater, respectively. Type of wastewater did not have any significant effect on other parameters. In generall, with respeet to the amount of SAR, NO3-N and TOC in the leachate as well as Ni and Cd specially in the raw wastewater and their hazardous consequences, their long-term disposals on soils need sound and suitable management practices.

Pedotransfer functions (PTFS) are useful means of prediction many properties of the soil, and especially the hydraulic characteristics of this porous media. The main advantages of this functions, as compare to conventional methods used to directly estimate soil hydraulic properties, is that they are not time-cost consuming. Different approaches such as classic linear and non linear regressions, artificial neural networks and regressions tree are being employed to develop the PTFS. Rosetta is a software package to predict soil hydraulic properties making use of artificial neural networks- based PTFS. In the present study, the impacts of the type and count of input variables to this software, on the prediction of the moisture retention curve and saturated hydraulic conductivity were evaluated in some soils from northern region of Iran, classed as of Loam and Clay Loam textures (USDA). Our results indicated that addition of bulk density as input variable decreased the performance of moisture retention curve prediction in both textural classes. Addition of bulk density showed on RMSE, ME, GMER and GSDER a positive and negative effect in Loam and Clay Loam textures, respectively. Addition of one or two moisture retention point(s) (the moisture content at matric potential of -33 and -1500 kpa) significantly decreased the RMSE at the medium range of matric potential (i.e. -33 to -500 kpa) and especially at -33 kpa. All of the studied PTFS tended to underestimate both saturated hydraulic conductivity and moisture content at different matric potential.

Heavy metals enter to human food chain through the plant and soil contamination. It is very important to evaluate the affecting factors on plant uptake of heavy metals. In this study the effects of copper and zinc availability on cadmium uptake of root and shoot of corn and sunflower was investigated. The experiment was carried out with a factorial arrangement, two species of plants (sunflower and corn), two cadmium concentrations (0.02 and 0.05 mg /l) and three concentrations of zinc and copper (0, 0.025 and 0.05 mg/l for Zinc and 0, 0.01 and 0.02 mg/l for copper) based on a completely randomized design with three replications. The results showed that copper and zinc availability had no effect on cadmium uptake of corn plant. The highest concentration of cadmium in root corn was observed in 0.05 mg/l of cadmium concentration without copper application. In sunflower, the addition of 0.05 mg/l zinc to medium decreased cadmium uptake in 0.02 and 0.05 mg/l cadmium treatments. The synergistic effect of cadmium and zinc was observed in 0.05 mg/l cadmium and 0.025 mg/l zinc treatments. Zinc concentration had a positive effect on cadmium uptake in root and shoot of sunflower in this treatment.

Poultry manure contains considerable nutrients and its application to agricultural land may boost soil fertility. In order to study the effects of poultry manure and its incorporation method with soil on soil chemical properties, a field experiment was conducted at the Ecological Research Center of Zagroos, 30 kms from northeastern of Khorramabad for two consecutive years (2004 and 2005). Treatments were arranged in a split plots layout based on randomized complete block design with four replications. Two incorporation methods of poultry manure incorporation with soil by furrower and disk+furrower as the main plot, and different amounts of broiler litter including zero, 10, 20 and 30 Mg ha-1 as subplot were considered. The results suggested that the phosphorus, zinc and cooper concentration as well as EC of soil were much greater in the disk+furrower treatment relative to the furrower treatment. However, the amount of total nitrogen and corn dry matter for the furrower treatment was significantly more than disk+furrower treatment. Averaged across years and incorporation method, maximum EC, organic matter, macronutrients and micronutrients concentration of soil and corn dry matter were obtained by applying 30 Mg ha-1 poultry manure. However, no significant differences were observed between 30 Mg ha-1 with 20 Mg ha-1 poultry manure for the EC, organic matter and potassium. The organic matter and concentrations of total nitrogen, phosphorus and micronutrients in soil for the second year were significantly greater than those for the first year. Results suggest that high rates of manure application are not sustainable and will lead to phosphorus accumulation and soil salinization. Thus, that incorporation of 20 Mg ha-1 poultry manure with soil by furrower might be appropriate for maintaining or increase of soil fertility and fairly corn production under conditions similar to this experiment.

Use of deficit irrigation to conserve water by minimizing leaching fraction during an irrigation season, or even across several irrigation seasons causes salt accumulate within the root zone. Naturally, salinization of the root zone is exacerbated when marginal waters are used. In this situation plants are experiencing simultaneously drought and salinity stress. Various mathematical models are exist for plants response to combined drought and salinity stress and its corporation in water uptake. The reduction functions are classified as additive, multiplicative and non coseptive models. Because transpiration is the largest component of the water budget in arid systems, the efficacy of models to simulate water and salt movement is depended on their ability to predict transpiration. In this study six different macroscopic reduction functions; Van Genuchten (additive and multiplicative), Dirksen et al., Van Dam et al, Skaggs et al and Homaee were evaluated in greenhouse condition using tomato data were exerted. This experiment was performed based on completely randomized design with three replicates and eight levels of salinity (0.75, 1.5, 2.5, 3.5, 4.5, 6, 8 and 10 dS/m) .Drought levels carry out as matrix potential during the experiment. The result of this study indicated that without salinity stress, all reduction function have a good agreement with measured data. Also, The result of this study indicated that the crop response to drought and salinity stress is additive low salinity level and is multiplicative at salinity level above 3.5 dS/m. among multi model, reduction function of Skaggs et al and Homaee's models were better fitness to measured data than the other functions.

The aim of this study is to evaluate the effect of loss methods application on run-off volume and hydrograph shape used by hydrologic models. In this research, four loss methods including constant loss (j index), initial loss-loss rate, SCS and constant fraction approach were applied to be evaluated. To do this, Clark Rainfall- Runoff model was applied for 24 storm events from kasilain basin. Then, the characteristics of calculated hydrographs were compared with the same characteristics of the same observed hydrographs. The result of statistical analysis showed that methods of SCS, initial loss-loss rate, constant loss (j index) and constant fraction loss have relative advantage respectively to be used for the mentioned basin.

Settling basins are essential hydraulic structures which have to be designed and constructed at all river water intakes to remove most of suspended sediments which enters the intake by flowing water. There have been many techniques for designing these structures. To simplifying the design procedure, some of these techniques have been applied many assumption and some others are so complicated which are difficult to apply or needs many data for design purpose. There are also some applicable methods which have been developed based on experimental or analytical procedures, but their results are not well known. Thus it is the purpose of this paper to compare these available methods. To do so extensive experimental tests were conducted in a flume of 8.0 × 0.3× 0.5m using three different sediment concentrations under three Froude numbers. Field tests also were conducted in an irrigation rectangular concrete canal of 200 meter long, 1 meter wide and depth. Field tests also have been conducted under there different discharges different sediment concentration. Then the experimental data was used to determine the trap efficiency of settling basins by different methods. The predicted values were compared to the measurement values. The result indicate that the method of Swamee and Tyagi over predict the trap efficiency. This method was found to be more sensitive to the input data. Result obtained by the methods of Jin and Kaveshnikov were found to be more close to measure data than Raju and Garde methods. In this study a coefficient of Jin method in irrigation settling basin was determined for best estimating of.

Bottom rack intake is one of the most appropriate structures for diverting water in steep rivers. The problems of corrosion, deformity and clogging of the bottom racks in long term, inspires a new system of bottom intake in which a filled trench of porous media is replaced by the bottom racks. Diversion of a specified amount of discharge through the porous media when void space in the granular material are filled with fine sediment in comparison to the bottom racks, requires much larger structure. However, for the new system of water intake, lower cost of construction and maintenance and higher compatibility with the river morphology in long term are considered as major advantages. The present research deals with an experimental model with two-storey channel, the lower one is used to divert water through the porous media and the upper one is used to convey the remained flow. Measurements of the diverted discharge were performed for different rates of flow, grain size distributions as well as surface slopes of intake with clear water and sediment flow. The influence of clogging phenomena on diverted discharge is also examined. The experimental results show that the effect of clogging in sediment flow in comparison to the clear water is decreased as the surface slope of the porous media is increased. It is revealed that the discharge coefficient of bottom intake when clear water is passed through the channel is varied in the range of 0.06 to 0.13. When sediment flow is passed over the bottom intake, due to clogging phenomena discharge coefficient is reduced up to 5 to 35% in comparison to the clear water. Experimental equations prepared for the discharge coefficients show that the significant factors affecting the efficiency of the water intakes are grain size distribution and surface slope of the bottom intake. The results show that the discharge coefficients for the water intake with the clear water and sediment flow when the above mentioned factors are selected appropriately are close to each other.

For investigating the effect of bed form in alluvial channels on the amount of bed load transport, a set of experiments was carried out in a tilting flume under unsteady flow conditions (hydrograph). The produced hydrographs were in triangular form with a maximum discharge of 30 to 45 lit/s/m. Three size of sediment particles were used with d50 d equal to 1.5, 2.1 and 3.0mm, clear water without any feeding was supplied from upstream. To analyze the time varying of bed resistance, a numerical model with initial and boundary conditions was used and its outputs were depth, velocity and discharge. The results showed that the inflow made considerable erosion at the starting time of flowing near the channel inlet, and this is a cause of producing bed form, increasing roughness and bed resistance. However, by the time the erosion trend was declined with increasing discharge. Despite of increasing flow turbulence, Froude number and bed erosion decreased gradually when the discharge approaching to its maximum value increasing flow depth. In this process, because of bed elevation changing along the flume, Froude number at any point is different from the other points and bed particles move toward downstream as a progressive wave. The bed resistance coefficient, n, was increased at the start of inflow time and after a proper time it was again increased, and this matter has very important role in sediment transport for non cohesive beds.

Khuzestan province accommodates the largest oil-fields with huge petroleum production in Iran. Oil spills through transportations, oil pumping station and storage tanks are the cause of frequent contamination in land areas, including crop fields, imposing great damages to soil ecology. Thus, oil removal from contaminated soil by advance technologies such as bioremediation seems to be of vital necessity. The aim of this work was to study the effect of agricultural fertilizers and sewage-sludge application on bioremediation of oil-contaminated soil. Soil samples (5kg) were artificially contaminated with crude oil to a level of 1%. Fertilizers treatments were applied in 3 levels of 0, 1 and 2 ton/ha in 3 replicates. The soils were kept in normal moisture aerobic environment for 5 and 10 weeks. The soils were then analyzed for hydrocarbon-degrading heterotrophic bacteria count. Oil degradation was measured by oil Soxhlet extraction method. The results showed that the hydrocarbondegrading and heterotrophic bacteria count in all the treatment increased with time. The result showed that hetrotrophic bacteria population increased from 6×103 cfu/gr soil to 1.4×108 cfu/gr soil Also, C/N Ratio decreased from 6 to 3. GC results indicated that all normal paraffin and isopernoids i.e. Phytane and Pristane decreased from 50 to 90 percent in all treatments moreover, the result indicated that application of fertilizers in 2 ton/ha rate in oil-contaminated soil lead to greater rates of biodegradation after 5 weeks, and could be introduced as the best suggested condition. Rates of biodegradation after 5 weeks.

Stepped spillways are of most important hydraulic constructions to dissipation energy of water flow. These constructions are used in opening channel to transfer water from upper level to lower level. Because of considerable effect of steps on flow dissipation energy and also the resulted developments in construction of roller competed concrete RCC, the mentioned constructions have drawn hydraulic engineers’ attention. In this research, physical models with three water chute slope in downstream face were used to survey natural air entrainment point in skimming flow .So three different slopes 1:1, 1:0/9, 1:0/7 (vertical & horizontal) were used in chute section after the standard crest parabola and before the steps start. Then the models were installed in hydraulic lab flume of Shahid Chamran University. The experiments were taken for 5 different flows per unit width (with amplitude 0.036 to 0.072 m2/s). The observations show that entrainment happens in water surface at certain distance from crest during the flow passes over the crest (Li). Results showed that crest downstream face geometry can cause change in flow hydraulics leading to change in boundary layer development because of different created (Li). Also it was seen that the 1:1 crest in comparison with other slopes, performs better hydraulically and creates a shorter entrainment point length (Li). In this paper the important results have been shown in the form of different tables and curves.

Nowadays, measuring water quality is very important for comprehensive management of water resources. Suspended sediment is one of the most important water quality factors which greatly affect environment health. However, its measurement needs too much time and money. It was therefore tried in the present study to assess the applicability of modeling relationship between suspended sediment concentration and some easily accessible and cheap water quality factors. Towards this attempt, 61 water samples were taken during October 2007 to July 2008 from main outlet of Tarbiat Modares University Forest Watershed as a representative condition governing northern Iranian forest areas. The samples were taken during different hydrological conditions and corresponding lab analyses were consequently made. The results of regression modeling ultimately proved the relationship between suspended sediment concentration and turbidity, alkalinity, and phosphate with correlation coefficient beyond 0.264 (p=0.006), 0.088 (p=0.018), 0.987 (p=0.001) and respective estimation and verification errors of less than 78% in all classified periods, base flow, and flood conditions, respectively. The models obtained during the study can be then used for estimation of suspended sediment concentration in different hydrological situations.

Evapotranspiration as one of the important elements in agriculture has a considerable role in water resource management. Therefore, using a more exact estimation method is an essential step of agricultural development, especially in arid semi-arid area. In this research, in order to exact estimate of garlic evapotranspiration using lysimeteric data, an artificial neural network (ANN) model was developed. Maximum and minimum air temperatures, maximum and minimum relative humidity values, wind speed and sunshine hours were used as the input layer data. The crop evapotranspiration was measured using 4 lysimetres of 2×2×2m of the Bu-Ali Sina agriculture collage’s meteorology station during 2006-2008. Statistic indicators RMSE, MAE, STDMAE R2 were used for performance evaluation of the models. The results showed the more exact method concerned to the multilayer perceptron (MLP) model with the back propagation algorithm. The 6-6-1 layout with Levenberg- Marquat rule and sigmoid function had the best topology of the model. The evaluation criteria were 0.088, 0.07 and 0.061 mm/day as well as 0.88, respectively. The results also showed that the average daily garlic evapotranspiration were 8.3 and 6.5 mm based on the lysimeter ANN methods, respectively. Overall, evaluation of ANN results showed that the errors of ANN were negligible. The ANN showed high and low sensitivity to maximum air temperature and minimum relative humidity, respectively.