Iranian Journal of Soil and Water Research
Year:2018 | Volume:49 | Issue:3 |Papers Count:20

These days, one of the most important environmental problems is soil pollution due to the contamination by petroleum hydrocarbons. One of the methods for reducing of soil contamination is the use of the electrokinetic process for remediation of hydrocarbons contaminated soils. Electrokinetic process causes the movement of water, ions and charged particles in the soil by electric field voltage. In this study, the effect of pH control in catholyte and anolyte on electrokinetic for removal of petroleum hydrocarbons from a clay soil, was evaluated. For this purpose, two experiments; one without pH control and second with pH control (in the range of 6-9) in electrolytes were carried out. Initial concentration of petroleum hydrocarbons in soil was 5%. The amount and type of petroleum hydrocarbons in the soil samples were measured by GC-MS. The results of both experiments showed that after 30 days, and 1 Vcm-1 electric field voltage, the highest percentage hydrocarbons was near anodes with little movement in the middle column. The average of petroleum hydrocarbons removal of two experiments was 16. 67% and 31. 5%, respectively. In addition, in the second experiment, about 26% of paraffin hydrocarbon and 37% of naphthalene hydrocarbons were removed from the soil column.

The water crisis is one of the fundamental issues in arid and semi-arid regions like Iran. Therefore, the use of unconventional water resources, where good quality water is not available, is increasing. One of these resources is treated wastewater which in addition to the water supply can also provide some of plants nutritional requirements. The statistical design used for this study was a factorial design experiment based on a completely randomized factorial design having two types of irrigation water with four levels of plant water stress: absence of plant water stress (control), low stressed (80%), moderately stressed (60%), and severely stressed (40%) with three replications. Analysis of variance showed that irrigation with treated wastewater and normal water affects shoot wet and dry weights of crop, ear weight, root wet and dry weights and plant height and diameter. In other words, plant growth depends totally on the type of water for irrigation and possibly on presence of nutrients and organic matter in the wastewater. Results showed that irrigation with treated wastewater increased wet and dry weights of shoots and roots of corn. With exerting more water stress, wet and dry weights of shoot and root were reduced, however, this reduction in treated wastewater was lower when compared to normal water. Shoot wet and dry weights related to treated wastewater without stress (100%) had the highest values 874/3 and 306 respectively which show an increase of about 45. 5 and 59. 2%, respectively when compared to normal water under severely stressed condition (40%). Therefore, deficit irrigation with treated wastewater significantly increased the yield of corn rather than deficit irrigation with normal water. The use of treated sewage along with a permanent water quality monitoring network is recommended.

The water crisis is one of the fundamental issues in arid and semi arid regions like Iran. Therefore, the use of unconventional water resources, where good quality water is not available, is increasing. One of these resources is treated wastewater which in addition to the water supply can also provide some of plants nutritional requirements. The statistical design used for this study was a factorial design experiment based on a completely randomized factorial design having two types of irrigation water with four levels of plant water stress: absence of plant water stress (control), low stressed (80%), moderately stressed (60%), and severely stressed (40%) with three replications. Analysis of variance showed that irrigation with treated wastewater and normal water affects shoot wet and dry weights of crop, ear weight, root wet and dry weights and plant height and diameter. In other words, plant growth depends totally on the type of water for irrigation and possibly on presence of nutrients and organic matter in the wastewater. Results showed that irrigation with treated wastewater increased wet and dry weights of shoots and roots of corn. With exerting more water stress, wet and dry weights of shoot and root were reduced, however, this reduction in treated wastewater was lower when compared to normal water. Shoot wet and dry weights related to treated wastewater without stress (100%) had the highest values 874/3 and 306 respectively which show an increase of about 45. 5 and 59. 2%, respectively when compared to normal water under severely stressed condition (40%). Therefore, deficit irrigation with treated wastewater significantly increased the yield of corn rather than deficit irrigation with normal water. The use of treated sewage along with a permanent water quality monitoring network is recommended.

Abstract: Due to the vital role of phosphorus as an effective element in plant cell metabolism, it is considered as an important macro-nutrient for plants. Introducing new cultivars of plants that take up and use phosphorus efficiently can reduce financial and environmental cost of phosphate fertilizers. Rapeseed as an important oilseed crop is widely grown around the world, including Iran. This greenhouse experiment was conducted to determine relative use or acquisition efficiency of seven winter rapeseed cultivars (Talaye, Okapi, L72, Gabriela, Karaj, Brutus, Elvis) in deficiently (0 mg P kg-1 add to soil with 4. 6 mg Olsen P kg-1 ) and adequately supplied P condition (80 mg P kg-1 add to soil). Shoot and root dry weight, leaf area, root volume, P and Ca uptake in root and shoot and P efficiency was measured and compared. The rhizobag technique was used for accessing rhizosphere soil. Based on the results, cultivars such as Gabriela with higher P uptake efficiency produced more biomass in phosphorus deficiency condition. There was significant variation in PE among the cultivars ranging from 0. 25(Elvis) to 0. 62 (Gabriela) and PACE ranged from 0. 16 (Elvis) to 0. 47 (Gabriela) and PUI (g2 SDW mg-1 P) ranged from 0. 12 (Elvis) to 0. 38 (Gabriela). Interaction effect of soil type (rhizosphere and non-rhizosphere) and P rate on soil pH was significant. It seems that P efficiency and biomass production in these cultivars was primarily due to their acquisition efficiency of P and Ca with larger root system and increase in P mobility and uptake from the soil and P use efficiency was in the next order of importance at P stress environment.

Hydrological modelling is usually used as a tool for predicting watershed hydrological response by water resources planners in flood forecasting and water resources management. Identification of the Nash-cascade model parameters as a practical model in simulation of flood hydrograph is very important in watersheds with limited data. The aim of this study was determining the Nash model response to variations of input parameters ranges (number of reservoirs and storage coefficient), and best subset combination to simulate unit hydrograph in the Jafar-Abad watershed, Golestan Province. The forty three rainfall-runoff events were used to derive that index unit hydrograph of the study area using S-curve technique. Then, the response of the Nash model results output was assessed considering random generated n, and k parameters through 3220 synthetic simulation and model efficiency was assesses using Nash-sutcliffe criteria. The results showed that the model has produced acceptable results in different values of n, and k input parameters and the model efficiency were more than 0. 6 with ranges of 10-30 for n parameter and 0. 01-3 subset of k values. The response of the Nash model in higher k and low n value subsets, showed the perfect simulation results. Also the results indicates that the storage coefficient parameter had an effective influence on determination of optimal input model combination, while a suitable model results is possible in different values on (n) number of reservoirs. In conclusion, identification of a precise value for the storage coefficient can greatly improve the simulation results. The results and the used approach can be used to determine the optimal model response regarding input parameters in similar ungauged watersheds.

Organic residues processing and their reversion to soil is helpful to build up a sustainable agriculture. Biochar is product of organic residue pyrolysis. Biochar chemical and physical characteristics are significantly affected by pyrolysis temperatures and its feedstocks. Therefore an experiment was conducted to evalute some properties of biochar produced from four feedstocks viz: sugarcane bagasse, rice straw, wood sawdust and conocarpus leaves, which processed by three pyrolysis temperatures vis: 400, 700 and 900° C. The treatments replecated three time and laid out in a factorial experiment with the completely randomized design. Results showed that each group of treatments separatelye as well as their interaction had significantly different effect on biochar pH, EC, CEC, specific surface area, C/N ratio and total element concentration as well as pb and cationic micronutrients availability. Increasing the pyrolysis temperature from 400 to 900° C, decreased CEC in biochar drived from rice straw, conocarpus leaves, sugarcane bagasse and wood sawdust by 73/9, 37/7, 36/0 and 21/9 cmol+/kg, respectively. But increasing temperature from 400 to 900° C, improved specific surface area of bagasse, rice straw, sawdust and conocarpus leaves biochar by 153/3, 241/1, 283/9 and 21/2 m2/g, respectively. It is suggested that at pyrolysis temperatures of 400° C with prioritize of biochar derived from conocarpus leaves, 2-rice straw, 3-sugarcane bagasse and 4-wood sawdust can be used to improve cation exchange capacity as well as improving available nutrients reservoir.

The mobility and bioavailability of heavy metals in soils is dependent upon redistribution processes between solid and solution phases and among solid-phase components. In order to study the effect of nano zero valent iron (nZVI) on chemical forms of Cd and Pb in soils, an experiment was conducted as a factorial in a completely randomized design in three replications with 4 levels of nZVI (0, 1, 2 and 4 %), 4 levels of incubation time (1, 2, 4 and 8 weeks) and two soils. Chemical distribution of metals in soil was determined using sequential extraction method during mentioned incubation times and the reduced partition index (IR) and mobility factor (MF) of metals were calculated. Application of nZVI significantly (p ≤ 0. 01) decreased the exchangeable and carbonate fractions and increased iron and manganese oxide bound fraction in comparison to the control treatment. The IR Values increased and MF values decreased with increasing nZVI levels and incubation time, result in a decrease in MF in soils. It is concluded that addition of nZVI in soil significantly could decrease MF of Cd and Pb in contaminated soils.

Estimating effective soil hydraulic properties for largescale is an outstanding challenge in hydrologic modelling. The aim of this study was to provide effective van Genuchten-Mualem hydraulic parameters at localscale through topography-based Upscaling Pedotransfer functions (PTFs) and spectrotransfer functions (STFs, SPTFs). The Zanjanrood sub-watershed with an area about 250 Km2 was selected as the study area for this research. hereby, a topography-based aggregation scheme, the so-called power average operator, PAO, was used to upscale (1Km×1Km) point scale parameters of, , and. With respect to the results, considerable and significant correlations (R>0. 50) were obtained between measured and estimated hydraulic parameters. Upscaled STFs showed the largest and significant correlations with upscaled measurements of (0. 65), (0. 70), (0. 86), while upscaled PTFs performed best for (0. 55). The PAO performed best in the pixels which have the highest topographic index (CTI). The biggest R values were obtained between shape parameters (i. e., and ) andthe standard deviation CTI as well as between and with the average CTI. The ASAR estimated soil moisture values appeared to be significantly (p<0. 005) correlated (-0. 453) with the average CTI. The results of this study indicate that the topography is an important factor in characterization ofeffective soil hydraulic properties at localscale.

Due to the effects of heavy metals on human health, removing them from the environment is essential. In this study, performance of several adsorbents in the removal of Pb from the soil solution was evaluated. A factorial experiment was conducted in a randomized design with three replications. Treatments included three types of adsorbents (zeolite, sunflower biochar and active carbon), four levels of Pb (0, 300, 600 and 900 mg/L of lead nitrate) and three different soil samples. According to the results, the best pH for absorbance of Pb was 5 and the proper balance time was 24 hours. Also, by increasing the adsorbent weight, the removal of Pb from the solution increased. In most cases Langmuir model described the data better than Freundlich. Since the total concentration of Pb desorption with zeolite and Biochar was less than active carbon, these adsorbents have higher efficiency than active carbon.

A 2-D numerical model employed to analyze submerged jump through the sluice gates. The results compared versus existing experimental data and the currently exercising equations. Afore mentioned laboratory data cover a wide range of submergence ratio. The standard model was utilized as a closure model for analyzing turbulence effects via OpenFOAM toolbox. Free surface captured using VOF method. Water surface profile, velocity distribution along flow depth, forward flow and roller zone specifications acquired after running model in different conditions analogous to experiments. Since the sub-surface flow is not counted in 2-D model, the non-dimensional velocity profiles show that the model overestimates velocities. Submergence ratio proved significant impression on potential core height and tail water depth. The discrepancies between model and experiments reduced in developed flow region further from the gate. This effect associate with diminishing turbulences and consequently approaching to a real 2-D flow. Defining appropriate boundary conditions conferred.

The aim of this study was to evaluate the influence of Floating Covers on the reducing evaporation from free water surface. In this study three types of covers (Polystyrene, Polystyrene with aluminum and polycarbonate) on the surface of 3 reservoirs (with three repetitions for each covers) were used. Changes in water depth of covered and uncovered reservoir were measured in one year from October 2014 until November 2015. Then the evaporation results of covered and uncovered trials were analyzed in form of a randomized complete block design with three replications using SAS software at confidence level 99% (P<0. 01) and Duncan test. The rate of evaporation reduction using Polystyrene, Polystyrene with aluminum and Polycarbonate, are 85. 60%, 83% and 76. 5%, respectively. These amounts represent a good performance of three covers in reducing evaporation from reservoirs. Although Polycarbonate cover represents better and proper performance in relation to durability.

Subsurface drainage is constructed in the paddy fields with the purpose of drying of land at the time of rice harvest, mid-season drainage and lowering water level after the rice harvest. Most drainage equations have been developed for non-paddy land. However, given the unique special conditions of paddy fields in Guilan province (due to heavy textured soils with low permeability, heavy rain and shallow impermeable layer) compared to non-paddy lands, therefore introduced the equation that is most compatible with these conditions. So in this study, steady and unsteady equations were evaluated in estimating space of subsurface drainage for a second crop after rice harvest. Drainage treatments included: six conventional subsurface drainage systems including drainage system with drain depth of 0. 8m and drain spacing of 7. 5m (L7. 5D0. 8), drain depth of 0. 8m and drain spacing of 10m (L10D0. 8), and drain depth of 0. 8m and drain spacing of 15m (L15D0. 8), drain depth of 1m and drain spacing of 7. 5m (L7. 5D1), drain depth of 1m and drain spacing of 10m (L10D1), and drain depth of 1m and drain spacing of 15m (L15D1). From the rainfall occurred during the experiment, a three-day rainfall with a mean value of 23. 9mm was selected for decision on the best equation. The equation that estimated the drainage space in the above rainfall with the least deviation from the best drainage treatment was chosen as the best drainage equation. The results showed that Ernst-Hooghoudt equation and Bouwer and Van Schilfgaarde equation combined with Hooghoudt equation estimated drainage space with the least deviations from the best drainage treatment (L10D0. 8) and were selected as the best equations in the second cultivation season and the Delroix equation was introduced as the weakest equation in the design of subsurface drainage for paddy field in order to provide suitable conditions for the second cultivation.

This research was performed to investigate the effect of tire ash enriched Arak municipal waste compost on the changes in Zn availability in a Cd polluted soil. Treatments were consisting of applying Arak municipal waste compost (0, 15 and 30 t ha-1) enriched with 0 and 200 kg ha-1 tire ash in a polluted soil (0, 5, 10 and 15 mg Cd kg-1 soil) and plant in this experiment was sorghum (Kimya CV. ). Increasing the loading rate of Arak municipal waste compost from 0 to 15 t ha-1 in a Cd polluted soil (10 mg Cd soil-1) caused an increasing in DTPA extractable-Zn by 80 percentage. Similar to this result, after 60th from the experiment, the root and shoot Zn concentration were increased by 40 and 60 percentage, respectively. Applying tire waste had an effectiveness role on increasing Zn availability, as, applying 15 and 30 t ha-1 tire ash enriched Arak municipal waste compost in a Cd polluted soil (10 mg Cd kg soil-1) caused an increasing in DTPA extractable-Zn by 22 and 26 percentage, respectively. While the shoot Zn concentration was increased by 13 and 20 percentage, respectively. The result of this study showed that greatest shoot Zn concentration was to the treatment with applying 30 t ha-1 Arak municipal waste compost enriched with tire ash in a non-polluted soil. However, the type and physiological effect on the changes in Zn availability cannot be ignored.

In this research tried to examine the transport and dispersion characteristics of rockfill media with application of the two completely flowthrough discharges, two media diameters and five injection masses. Firstly by means of a digital EC sensors and related data logger system and software, the experimental BC curves have been extracted and then by application of method of temporal moments, the longitudinal dispersion coefficient and other parameters like mean residence time, variance and coefficient of skewness have been computed. Afterwards, by using analytical solution of classical advection dispersion equation and extracted coefficients from method of moments, the theoretical BC curves have been calculated and were compared with experimental ones. The applicability of method of moments have been approved by the results and also concluded that (except the climax point, in some cases) the theoretical solution can cover all regions of experimental BC curve.

In order to investigate the effect of amount and salinity of irrigation water equal to 0. 5, 3 and 6 dSm-1 caused by NaCl (S0. 5, S3 and S6, respectively) and irrigation levels equal to 60, 80 and 100% of full irrigation (E 60, E80 and E100, respectively) on nutrients and growth spinach, and also soil salinity profile, an experiment was carried out in the pot in a factorial method as a complete randomized design with four replications. According to the results of the research, salinity and water had effect on plant height, number of leaves; leaf area and chlorophyll index so that increasing salt amount in irrigation water and decreasing water usage leaded to decreasing chlorophyll index, height and number of leaves in the plant. Due to increasing salinity to 3dS. m-1, concentration of P and N had increased significantly and K had decreased to S0. 5, insignificantly. Content of P and N decreasing in E60 treatment to E100 was 1. 3 and 0. 46% respectively and the Content of K increasing was 1. 62% which was not significant. Study of soil salinity profile showed that in 0-6 cm soil layer for 3 and 6 dS. m-1 treatments, salinity increased about 23 to 53% to 0. 5 dS. m-1 treatment. Due to saline water 6 dS. m-1, soil with the average of salinity is acceptable.

To study the effect of different amounts of municipal compost and sewage sludge on soil properties and yield of maize after one and five years of consumption, a scientific experiment was conducted in Rudasht irrigation and drainage research station of Isfahan, Iran. The applied treatments of 25 and 50 t/ha of municipal compost and 15 and 30 t/ha of sewage sludge and control treatment (non-application of organic fertilizer) before planting, were used in constant plots in a randomized complete block design with three replications. As a result of organic fertilizer consumption, the pH decreases and concentrations of some essential elements concordant with the lead element increased significantly in the soil. The amounts of micro and macro elements were also increased in harvested corns. It was clear that the concentrations of those elements have increased in soil and corn after five years compared with one year of organic fertilizer consumption. The yield of corn was increased significantly by five year of fertilizer usage in comparison with control treatment

Due to the limited water resources, the deficit irrigation would be one of the most relevant methods in this situation. The purpose of this study was to optimize the water consumption and nitrogen level simultaneously. In this research, two different irrigation strategies of 75% (I2), 50% (I3) and 25% (I4) of water requirement and full irrigation (I1) and different nitrogen treatments with application of 150 (N1), 112. 5 (N2) and 75 (N3) Kg/ha was investigated on yield production. Optimization of water and nitrogen showed that the proper yield function of soybean is the transcendental model among linear, Cobb-Douglas, quadratic and transcendental models. The optimum water and nitrogen levels of soybeans under water-nitrogen stress conditions was estimated 230 and 216. 5 mm of water and 150 kg of nitrogen in two years. The results showed that the yield production was increased by 33. 28% in N3 with deficit irrigation treatment (I2) as compared with full irrigation method.

In order to evaluate the effect of different amounts of natural and artificial soil modifiers on biological yield and grain yield of wheat, an experiment was conducted at the research farm of Kashmar high education institute. In this research, experimental treatments were included: four levels of A200 hydrogel (0(V0), 1(V1), 2 (V2) and 3 (V3) grams per kilogram of soil), four levels of vermicompost (0(V0), 2 (V1), 3 (V2) and 4 (V3) grams per kilogram of soil) and three levels of irrigation (40 (W1), 20 (W2) and 0 (W3) percentage of moisture loss). The experiment was carried out in a randomized completely block design in a factorial arrangement in a pot experiment in 144 pots. The results showed that the highest amount of biomass and grain yield in S3V3W3 treatment were 81. 7 and 35 gram in the pot respectively, and the lowest biomass and grain yield were in S0V0W1 treatment of 35 and 10. 2 gram in the pot respectively obtained. Application of A200 hydrogel and vermicompost had increased biological yield by 31. 88% and 18. 5% and grain yield by 23. 5% and 20. 25%, respectively. Under the conditions of this experiment, the interaction effect of A200 hydrogel and vermicompost compounds was not significant. The effect of A200 hydrogel and vermicompost on the grain yield was significant, as the highest value of grain yield was obtained in the treatment of 2 g/kg A200 hydrogel and 3 g/kg vermicompost and the highest value of biological yield was obtained in the treatment of 3 g/kg A200 hydrogel and 4 g/kg vermicompost. Separately use of A200 hydrogel and vermicompost is recommended for achieving maximum biological yield and grian yield.

Control of hydraulic jump to reduce damage to the structures of downstream is one of the issues of interest to researchers. Although several researches have been conducted on the application of rough bed to control submerged jump but, any study has not been published on the simultaneous application of the adverse slope, bed roughness and the positive step. In this research, the effect of different adverse slopes, bed roughness and positive step height were simultaneously investigated on characteristics of submerged hydraulic jump in Froude numbers from 4 to 10 and submerge ratio from 0. 1 to 1. 5. The results showed that in each special Froude number, the length of submerged jump and its relative energy loss are more and less than these specifications for free hydraulic jump; respectively. In addition to, with increasing the submerge ratio, the average energy loss and the submerged jump length decreased 10 and 33%; respectively as compare to the classical state. Also, the thickness of the dimensionless boundary layer of submerged jump was 0. 37. On the other hand, the shear force coefficient (ε ) was calculated 4. 44 times more than the classic condition.

Due to increasing evapotranspiration and water resources scarcity, accurate estimation of crop water requirement is quite necessary. The existing improvements and the development of smart and automated devices in the field of agriculture have made lots of progress in agricultural required plant-environment measurements. In this study, design, construction and calibration of a portable small weighing smart lysimeter has been introduced. This device is capable of direct measurement for determination of crop evapotranspiration, crop coefficient and also to find the behavior of chemical compounds at desired soil depth and water. This study was conducted in an experimental farm located in Shahid Bahonar University of Kerman during years 2016-2017. In order to design the device the inner tank dimension was considered as 27 cm in diameter and 30 cm in height with stainless steel cover and outer cylinder with 40 cm diameter. Because of this weighing system, an aluminum alloy single point load cell has been used where it has 60 kg rated capacity. An automatic weather station installed near small lysimeter and recorded weather data such as rainfall, temperature, relative humidity, air pressure, sunshine hours and intensity of radiation. On the other hand for supplying crop water use, an automatic irrigation system with known time distances was installed near lysimeter’ s setup. An automatic drainage sensor at the bottom of lysimeter’ s cylinder determines excess water amount. Measuring soil moisture and soil temperature at desired depth are possible by their sensors. Load cell calibration was done by applied known weights to the small lysimeter. Then correlation diagram between known weights and lysimeter weight changes resulted in R2=0. 9998. Other sensors also were calibrated. Finally, lysimeter gets ready for cultivation surrounding a farm.