Iranian Journal of Soil and Water Research
Year:2013 | Volume:44 | Issue:4|Papers Count:10

In this study, technical and operational issues of 45 qanats in Hamadan, Semnan and Khorasan Razavi provinces were studied and executive strategies to improve water management in qanats were recommended. 15 qanats were selected and studied in each of the provinces. Discharge, quantity and quality of qanat water, geometric characteristics including longitudinal slope, length, and flow section areas were measured. Conveyance and application efficiencies and water use efficiency (WUE) from the cultivated areas downstream the studied qanats were evaluated. Results showed that conveyance efficiency was relatively high changing from 63 to 98%. Application efficiency in the cultivated areas downstream the studied qanats in different provinces varied from 31.9 to 69.7% being somewhat higher than observed application efficiency in the cultivated areas irrigated by other sources of water (i.e. wells and rivers). However, WUE from the cultivated areas downstream the studied qanats were essentially similar to the average of the country being about 0.86 kg/m3. The main issues of the studied qanats were ground water table falling due to periodical droughts and digging of wells around the qanats, causing large variation in qanats dicscharge, maintenance management issues, lack of qanats experts, deficit budget for repairing and maintenance of the qanats, entrance of rubbish, sewage and public ownership, tunnel and well collapsing due to lack of resistant covering, numerous owners and rural migration.

This study was conducted to investigate the effects of applying deficit irrigation on aboveground biomass, leaf area and root biomass for maize Hybrid 704 single-cross. Experimental treatments included 4 different irrigation levels, 5 growth stages with three replicates in a completely randomized factorial statistical design. Aboveground biomass, leaf area and root biomass in 4 longitudinal sections of root length were measured at different growth stages. Results indicated that different irrigation levels had significant effect on aboveground biomass, leaf area, root biomass of sectional root lengths and total root biomass (P<0.05). The maximum aboveground biomass, leaf area and total root biomass were observed at milk stage in both years. These values were 318.9 and 465.1gr for aboveground biomass, 6497 and 6533cm2 for leaf area and 32.3 and 36.6gr for total root biomass in 2009 and 2010, respectively. The optimum level of water stress with maximum root biomass for maize can provide useful information for scholars and engineers to increase irrigation water use efficiency under deficit irrigation management.

MTBE (methyl tertiary-butyl ether) is an Oxygenated organic matter which is widely used nowadays in some countries in unleaded gasoline. MTBE is a toxic substance which is absorbed quickly on water and soil and is one of the most important pollutants in soils and groundwater resources. In order to remove MTBE from the soil, using different experimental methods, determining reliable methods for specifying adsorption capacity of MTBE according to optimum value of affecting parameters and MTBE concentration in soil is the first and the most important step. Therefore, in this study contaminated Kaolinite clay soil samples were prepared with different concentrations of MTBE. Afterwards the maximum adsorption capacity of MTBE in the soil and effect of various parameters, such as: sample PH, contact time, MTBE concentrations and soil dosage of samples, on its value was investigated. The results showed that contact time and MTBE concentration have the most effect on maximum adsorption capacity of MTBE in the soil. Maximum adsorption capacity of MTBE in the soil determined equal to 1.15 g/kg considering optimum condition of effective parameters. Since Kaolin clay soils can be widely used certainly for removal of MTBE from contaminated soils, especially through electrokinetic techniques, thus, it is believed that Results of this study experiments provide specific guidance for future researches into MTBE adsorption capacity of Kaolinite.

The aim of this study was to investigate the effect of different amounts of hydrogen peroxide and iron resources in refining petroleum (Kerosene) contaminated soils using Fenton reaction. For this, ten complex soil samples around Tehran Oil Refinery were collected and after preparations were contaminated with two levels of 10 and 20% of petroleum (Kerosene) in triplicate. After reaching equilibrium conditions, soils based on Fenton reaction were treated with amounts of 0.006, (H1), 0.009, (H2), 0.012, (H3), 0.018, (H4), 0.059, (H5) and 0.088, (H6) eq of hydrogen peroxide. The three sources of iron as a catalyst included, no iron fertilizer (control), (F1), Sequestrine [EDDHA-Na-Fe] as a source organic iron (F2) and ferrous sulfate as a source of iron minerals (F3) was used. Experiments were conducted as factorial based on completely randomized design. The results showed that there were significant differences between the number of eq of hydrogen peroxide consumption, pollution levels, soil samples and iron sources on petroleum removal efficiency from the soil (P≤0.01). The results showed in all levels of hydrogen peroxide and soil samples, refining efficiency in 10% was more than 20 percent treatment of pollution. The maximum efficiency refining in 10% and 20% pollution level was related to H6F3(90.72 percent) and H6F2 (87.24 percent) treatments respectively and the minimum efficiency refining in both pollution level was observed in H1F1 (for 10% and 20% pollution level 54.96 and 41.91 percent respectively). A negative significant correlation between clay, CCE and pH with refining efficiency was observed in both the 10% and 20% pollution level. However, this correlation for sand was achieved positive.

To examine hydraulics of LNAPLs in soil, the retention curves of diesel fuel and water were both determined by hanging column method. The soil retention parameters were obtained based on van Genuchten, Brooks-Corey and Campbell’s models. In addition, the soil hydraulic conductivity for both fluids were predicted based on Mualem- Brooks-Corey, Burdine- Brooks-Corey, Mualem-van Genuchten and Campbell’s functions. The results indicated the magnitudes of the pore-size distribution parameters remained mostly unchanged and the bubbling pressure parameters were increased in diesel fuel-air compares to water-air system. The LNAPL was retained less than water owing to its negligible surface tension, yielding less needed tension to drain diesel fuel out from soils. In addition, the LNAPL retention curve was appropriately scaled based on the recommended scale factor. Due to high kinematic viscosity of diesel fuel and low soil retention for diesel fuel, the saturated and unsaturated soil hydraulic conductivity of diesel fuel was less than that of water.

The understanding soil erosion processes and the development of accurate erosion prediction models require understanding of detachment, deposition and sediment transport in rills. To evaluate the effect of soil type and flow stream power on the relative importance of flow driven processes of sediment transport, and on the boundary between the processes regarding to particle size, experiments were performed under six flow stream powers at the slope of 2% in the laboratory condition. A 0.05×0.05×2.5 m flume was used and time changes in sediment size distribution were measured during 40 minutes to evaluate sediment transport processes. The results supported: i) a hydraulically-dependent size selective pattern for particle transportation, and ii) transportation of different sizes of particles by different mechanisms including Suspension-saltation and Rolling. The results also showed that the particle size with minimum transportation, which has been considered as boundary between the suspension-saltation and rolling processes is unique for each soil, depends on its particle size distribution. This boundary is not changed by increasing flow stream power from 0.12 to 0.8 Wm-2.

This study was conducted to determine the spatial variability and mapping of available micronutrients iron, zinc, copper and manganese on 20,000 hectares of soils in South of Tehran lands in order to identify deficiency, enough and toxicity areas. 196 surface soil samples (0-25cm) to a regular grid network of 1000×1000m were collected and extracted by DTPA and TEA and concentrations of elements were measured by atomic absorption. The results showed that the micronutrient elements iron, zinc, copper and manganese have spatial variability and according to the different land utility have different concentrations. The best variogram models that were fitted for available iron and copper; exponential, zinc; gaussian and manganese; spherical. The average concentration of Fe, Zn, Cu and Mn were 2.6, 2.1, 1.2 and 3.5 mg/kg soil respectively. Based on the estimated critical level in Iran, all of soils have iron deficient, while for the zinc, 81 percent of the lands have a moderate, 18 percent adequate, and 1 percent high. About 76, 18 and 6 percent of the lands have a low to moderate, optimum level and high concentration of copper in the soils, respectively. Available of Mn in all of soils were low to moderate level. The matching of land use and management maps with mapping of each element showed that the areas with high levels of copper and zinc were in accordance with the highway, industrial and residential areas and irrigated with sewage water.

Biological soil crusts (BSCs) result from an intimate association between soil particles and cyanobacteria, algae, fungi, lichens and mosses in different proportions which live on the surface, or immediately in the uppermost millimeters of soil. Therefore BSCs cover the ground surface as a Coherent layer, and influence Primary Processes such as Carbon and nitrogen fixation and hydrologic Status. This study carried out in Qara Qir rangeland of Golestan province, northeast of Iran, to investigate the effects of BSCs on soil hydrologic indices. Four sites including covered of BSCs and without BSCs cover areas were selected. Infiltration rate, soil water content, available water content, organic carbon percent, and particle size distribution were measured in depths of 0-5 and 5-15 cm, with four replication. The gathered data were analyzed by nested plot, and the mean values comparison were done by duncan test. Results showed that particle size distribution did not differ among areas covered by BSCs and without BSCs. Infiltration rate, soil organic carbon, soil water content, and plant available water content were increased significantly in two mentioned depths due to the effects of BSCs. In general it can be concluded that BSCs improve soil hydrologic conditions.

Wheat flour is known as the best nutrients supplier for human. In this research, the effects of combined application of nitrogen fertilizer, farmyard manure (FYM), sewage sludge and municipal waste compost on nutrients concentrations of wheat flour (Triticum aestivum cv. Alvand) were studied in a randomized complete blocks design with 15 treatments and three replicates in Agricultural Research Station of University of Tabriz at field conditions. The treatments consisted of T1 (control, without organic and nitrogen fertilizers), T2 (150 kg urea/ha), T3 (300 kg urea/ha), T4 (30 ton municipal waste compost/ha), T5 (60 ton municipal waste compost/ha), T6 (30 ton sewage sludge/ha), T7 (60 ton sewage sludge/ha), T8 (30 ton FYM/ha), T9 (60 ton FYM/ha), T10 (T4+T2), T11 (T5+T2), T12 (T6+T2), T13 (T7+T2), T14 (T8+T2), and T15 (T9+T2). At the end of growth period, grain yield and wheat flour nitrogen (N), phosphorus (P), potassium (K), sodium (Na), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), cadmium (Cd) and lead (Pb) concentrations were measured in different treatments. The results showed that application of 150 and 300 kg urea/ha increased wheat flour P, K, Na and Fe concentrations and grain yield compared to the control treatment. Urea fertilization had no significant effect (P≤0.05) on flour Zn, Mn and Cu concentrations. Application of FYM, sewage sludge and municipal waste compost with and without urea fertilizer significantly increased grain yield and N, P, K, Fe and Zn concentrations of flour compared to the control treatment. Flour Na concentration was increased by application of organic fertilizers without urea, but was reduced by integration of them with urea. The flour Mn and Cu concentrations were increased by application of FYM and sewage sludge, respectively. The Pb and Cd concentrations of wheat flour were negligible in different treatments. In general, in order to increase nutrients concentrations of wheat flour and improving its quality, application of 150 kg urea and 60 ton manure or municipal compost or sewage sludge per hectare can be recommended at similar conditions.

Since arsenic pollution is one of issues of concern about human health, especially in industrial areas, studying its immobilizing methods and effective factors is necessary. In this research, some effective factors on arsenic immobilization in soils including reaction time, pH, Iron(II), zero valent iron (ZVI ) and zeolite-Fe were studied. The soil was spiked with As (III) as sodium arsenite at 300 and 440 mg kg-1 by using pure sodium arsenite salt. Test of time and pH by using Fe (II) and ZVI were performed as batch system in spiked soil with arsenic concentration of 440 (mg kg-1), 2% of amendments during 16 hours as reaction time. The effect of concentration on the initial concentrations of 0.5, 1.5 and 2.5 percent by weight of the amendments were studied. Surveying the effect of the factors including time and pH on As (III) IE (%) using zeolite-Fe was conducted in spiked soil with arsenic concentration of 300 (mg kg-1), 0.17% Fe dosage on zeolite within 16 hours as reaction time. The effect of initial concentration of iron-loaded zeolite, on IE (%) by zeolite containing 0, 0.005, 0.017 and 0.02 mg Fe was studied. According the results, at the first 15 minutes of experiment, Fe (II)’s reaction time and As (III) IE(%) was more than ZVI, but after 16 hours efficiency of ZVI became 96.55 (%) while As (III) IE (%) by using Fe (II) was 68.2. With increasing pH (6 to 10), As (III) IE (%) by Fe (II) and zeolite-Fe had been increased while ZVI acts better at pH’s below 8. The most efficiency of Fe (II) was in its least concentration. With increasing ZVI percentage and loaded Fe on zeolite, IE (%) had increased, too. Zeolite-Fe showed a good rate and efficiency, so that immobilized a large part of As (III) in the first 15 minutes of reaction time.