فصلنامه حفاظت منابع آب و خاک
سال هفتم شماره 4 (پیاپی 28، تابستان 1397)

The purpose of this research was to evaluate the production quality of synthetic envelopes produced in Khuzestan factories and their performance in north and south Khuzestan soils, using laboratory methods. For quality control of the manufactured synthetic envelopes, first KOMO Standard tests were conducted followed by laboratory tests using upflow permeameter designed by Vlotman for these soils. Measured parameters in these tests were, discharge, Gradient Ratio and soil particle movement from the synthetic envelopes for soils of Dehkhoda and Ramshir projects. All Three types of pp450 synthetic envelopes A, B, and C manufactured in Khuzestan passed KOMO Standard test evaluations in this investigation. As to permeameter test results and Gradient Ratio tests (GR) envelope C for Ramshir soils and A for Dehkhoda soils were found suitable. It is therefore recommended to use these synthetic envelopes produced in Khuzestan soils with caution. These envelopes are more suitable where water table is to be lowered slowly to prevent rapid soil moisture depletion.

Soil and water relations are so complex that the most advanced mathematical models can hardly be able to simulate them accurately. Retention curve and unsaturated hydraulic conductivity are among the most important factors in the study of water flow in the soil. Because the high variability and soil complexity, obtaining soil hydraulic properties directly is difficult, time consuming and costly and therefore it is necessary to estimate indirect methods. The purpose of this study was to determine the fractal dimension of soil moisture curve using fractal models and to investigate the relationship between the moisture curvature fractal dimension with hydraulic parameters, clay, silt and sandy percent in a wide area. For this purpose, some soil samples collected from different tissues from the regions of the country were collected and the variables of particle size, bulk density, organic carbon, salinity, pH and moisture content were measured in different suction. Finally, the parameters of the van Genuchten model as well as models Tyler-Wheatcraft and Rieu-Sposito fractals were calculated for soil particle size distribution. The results showed that van Genuchten model parameters have fractal behavior and can be quantified by using fractal models. The results also showed that the higher the amount of sand in the soil, the fractal decreases, but the clay content has a direct linear relationship with the Tyler-Wheatcraft fractal dimension. This means that by increasing the amount of clay in the studied soils, the fractional dimension of the Tyler-Wheatcraft (Dm) model also increases and with the increase in the amount of sand, the fractal dimension of the Tyler-Wheatcraft (Dm) model decreases.

Surface erosion is a one of the major factors of soil degradation and gradual decline in soil productivity. Little studies have been done on the surface erosion indices in the semi-arid rangelands. Therefore, this study was conducted to quantify surface soil erosion indices using the land characteristics in a semi-arid region. Five southern hillslopes with different slope gradients (9, 13, 17, 31 and 33%) which subjected to surface erosion were selected in Zanjan province. Soil samples were collected from two depths (0-5 and 5-15 cm) in four locations at a 2-m distance along the slope at two replications. A total of 80 soil samples were collected for analyzing particle size distribution. Soil surface erosion indices were determined using the proportion of particle diameter for given frequency in surface and sub-surface soils. Toward this, the proportion of particle diameter in the frequency of 40 (d401/d402), 50 (d501/d502), 60 (d601/d602) and 70 % (d701/d702) was computed. Additionally, proportions of mean weight diameter (MWDp1/MWDp2), geometric mean diameter (dg1/dg2) and geometric standard deviation (δg1/δg2) of surface and subsurface soils particles were determined. Based on the results, significant differences were found among the hillslopes in all soil surface erosion indices, whereas the differences for the locations along the hillslopes were not statistically significant. In the steep slopes, the frequency of fine particles (silt and clay) and organic matter content was very low in surface soil. Multiple linear regression analysis appeared a strong relationship between the MWDp1/MWDp2 and slope gradient (R2= 0.51, p

Given the importance of catchment basin output flow for surface water management, precise understanding of the relationship between the amount of runoff and climatic parameters such as precipitation and temperature is important. therefore the identification of parameters are important in the modeling process. In this paper, after homogeneity tests have been carried out for monthly precipitation, temperature, and runoff data in the Navroud Catchment Basin in Iran, two combinations of effective factors for runoff are considered according to Relief and Correlation algorithms. A new Relief Algorithm first identifies effective features within a set of data in an orderly manner especially when the amount of available data is low. The new method uses a data-related weight vector average and a threshold value. Applying support vector regression and the nearest neighbor method, monthly runoff was modeled based on the two proposed combinations. The results showed that support vector regression approach which utilizes a radial basis function kernel, yields higher accuracy and lower error than the nearest neighbor method for estimating runoff. The improvement is particularly noticeable for flooding situations.

In order to study the equilibrium, kinetic and thermodynamic of cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) adsorption by nano zero valent iron (nZVI) and nano copper oxide (nCuO), batch experiments carried out with different initial concentration of the metals at different time and temperature. The results showed that the removal efficiency and adsorption capacity of nano particles increased with increasing initial concentration. Among adsorption kinetic models, pseudo second order model was better fitted for experimental data (R2=0.99-1.00). The adsorption data were well fitted with Langmuir model compared to Freundlich, Temkin and Dubinin-Radushkevich models. Maximum mono layer adsorption (qmax) of Cd, Pb, Cu and Zn were obtained 218, 239, 242 and 215 mg g-1 for nano zero valent iron and 90, 176, 100 and 76 for nano copper oxide respectively. The sorption energy parameter (E) of Dubinin-Radushkevich isotherm and Gibbs free energy change (ΔG) indicated that the metals adsorption processes were physical and spontaneous. The separation factor of Langmuir (RL) indicated that the sorption reactions of metals by the nano particles is favorable (RL=0.03-0.50).

The irrigation of turf grass is the major factor to water consumption in advanced urban area. Therefore, reduce water consumption using subsurface irrigation system could be a new strategy for optimization of water requirement. The purpose of this study was to investigate the effect of subsurface irrigation system, sprinkler and superabsorbent polymers on quantitative and qualitative characteristics of turf grass. Experimental design was a split -plot with three replication in agriculture faculty of Tarbiat Modares university in 2014. During the experiment, some factors such as applied water volume, wet and dry weight of sprouts, sprouts length, color and length of roots were measured to express the differences between irrigation methods. The results showed that, without using superabsorbent polymer, subsurface irrigation could reduce 41% of water consumption compared to sprinkler irrigation. Meanwhile this reducing consumption was 51% using superabsorbent polymer treatment. Also, length of roots in buried porous clay capsules irrigation was significantly different at%5 level in comparison to sprinkler irrigation. The superabsorbent application had significant effect on increasing root growth but the other index, wet weight, length and color of Sprouts had no significant effect. According to the results of this research, application of buried using buried porous clay capsules is recommended in order to optimize water consumption for urban area located at arid and semi-arid regions.

River basin planning is an essential factor for sustainable development and land management. Therefore, sub-basins prioritizing and detecting morphometrically characteristics to identify the hydrological behaviors of watersheds and designing management strategies are very important. The aim of present study is to prioritize the flooding of the basin by distributional method and provide a method for determining the flood generating areas in the Tangrah watershed. To this end, the inputs of the rainfall-runoff model were extracted and then the model was calibrated and validated. For this purpose, the inputs of the rainfall-runoff model were extracted and then modclark model calibrated and validated. In the next step, in order to determine the flooding of homogeneous units and sub-basins with unit flood response method, sequential removal and replacement of these units and simulation of flood hydrographs for designed rainfall were carried out at the Golestan National Park's rain gauge station. Then the effect of each homogeneous unit and sub-basin on the total output hydrograph in the watershed was calculated. Finally, for a flood with a return period of 50 years and 100 years for non-statistical watersheds, a correlated multivariable correlation between morphometric parameters and flood index was presented. The results of the potential runoff production map with the return period of 50 and 100 years showed that the runoff production potential was upward downstream of the basin, and the homogeneous unit 116 was recognized as the most effective unit in the high runoff potential, which is due to more rainfall as well as The steep slope and high (CN) in this homogeneous unit, the runoff production potential is nearer the outlet of the basin than the upstream areas. The results of this study showed that by integrating the GIS and hydrologic models, we can investigate the interaction of physiographic and climatic factors on the spill potential of watersheds. Considering the peak synchronization and the flood roughing role in the rivers, prioritized sub-areas as desired.

Soil quality shows permanent ability of soil as a vital system as alive vital system in ecosystem under different utilizations. In this regard, indicators of soil quality as evaluation and decision-making criteria are used. This study conducted to investigate the effect of remaining fertilizer on chemical properties of soil in faba bean- rice cropping system including first cultivation, rice and second cultivation, faba bean by 15 fertilizer treatments for faba bean in the form of a factorial randomized complete block design with three replications in the field of Rice Research Institute of Iran for years 2012- 2015 (Including two periods of cultivation for rice and three periods of cultivation for faba bean). Experimental factors for faba bean comprised five nitrogen rates (0, 25, 50, 75 and 100 kg N. ha-1) from urea and three phosphorus levels (0, 50 and 100 kg P. ha-1) from triple superphosphate fertilizer. Results showed that increasing nitrogen rates reduced soil acidity and electrical conductivity increased. Also faba bean cultivation led to increase in organic carbon percentage (% 2.81), N (% 0.209), P (40.59 ppm) and K (237.69 ppm).The highest soil phosphorus was observed in P100 (42.69 ppm) in rice cultivation. The average yield of two- cycle production of rice was about 2770.95 kg. ha-1.

Optimized management and utilization of any system requires knowing the working conditions of the system, and optimized utilization becomes possible by evaluating the way the system works. Since various regions in Iran have arid and semi-arid climates, obtaining the actual wind drift and evaporation losses and also making optimized use of water has a great importannce. The present research intended to evaluate a classic semi-permanent sprinkler, to measure wind drift and evaporation losses, and to introduce an optimized model by using multivariate regression for the study region. The study was conducted in Part of the Moghan agro-industrial complex in Ardabil province at wind speeds of 0-3 and 3-6 and higher than 6 meters per second with three replications. Results in ADF 25º nozzle sprinkler model indicated that the efficiencies of the system at wind speeds of 0-3, 3-6, and higher than 6 meters per second were 82, 66, and 43 percent, respectively, and wind speed, temperature, relative humidity, nozzle diameter, and vapor pressure deficit (saturation deficit) were among the factors that influenced wind drift and evaporation losses. The wind factor had the most and vapor pressure deficit the least effect on wind drift and evaporation losses. Furthermore, the equation of the best fit line to the measured values for wind drift and evaporation losses under the prevailing atmospheric conditions in the region was as follows and the difference between results of the model and observed data was not significant in 1% level of confidence. Moreover, the measured and the modeled percentages obtained for wind drift and evaporation losses varied from 6 to 34 and from 11to 35 percent, respectively.