مجله تحقیقات آب و خاک ایران
سال پنجاه و سوم شماره 1 (پیاپی 73، فروردین 1401)

The aim of this research was to study the importance of the neighborhood scale in modeling the relationship between vegetation cover and morphometric variables using the classification and regression trees algorithm (CART) in southwestern of Iran. For this purpose, the second Modified Soil-Adjusted Vegetation Index (MSAVI2) was calculated from a Landsat 8 image, and eight morphometric variables were derived using the Wood method in four neighborhood scales (90×90, 150×150, 210×210, and 270×270 m) from a 30 m SRTM digital elevation model. The results of the Kruskal-Wallis test confirmed that in some sub-watersheds, neighborhood-scale change can have a significant effect on slope gradient, profile curvature, specific catchment area, LS factor, and topographic wetness index. The results showed that in each sub-watershed different morphometric variables are most related to the spatial distribution of the MSAVI2 index and the value of the Spearman correlation coefficient between them is slightly affected by the neighborhood scale. CART models based on the MSAVI2 index and 270×270 m morphometric variables with a kappa coefficient of 0.55 and 0.78, respectively, had the best performance in classifying vegetation types. The elevation smoothed, which is the least affected by the neighborhood scale, was recognized as the most important predictor in the CART model. However upscaling led to the increasing importance of other morphometric variables, especially slope gradient, in classifying vegetation types and finally improving the accuracy of the CART model. Overall, the present results indicate that the application of multi-scale geomorphometric analysis with respect to the geomorphology of the study area can improve the performance of prediction models related to vegetation cover to an appropriate extent.

Groundwater in arid regions such as Iran plays a very large role in drinking water supply and agriculture. One of the threats to the future of groundwater exploitation, could be the contamination of these resources by harmful substances. At present, about 60% of the water consumption of Varamin plain region and the total volume of water consumption in the drinking sector is provided from groundwater sources. One of the best ways to prevent groundwater pollution is to identify vulnerable aquifer areas. The SINTACS model has been used to assess the vulnerability of the Varamin plain aquifer. This method consists of seven parameters that after combining the parameters, the vulnerability index map is obtained. The index of this method varies between 92 and 168.Results show that the north of the plain is very vulnerable and vulnerability is low in the south-eastern parts of Jalilabad village and downstream areas of the plain, while the rest of the plain has moderate vulnerability. A three-dimensional numerical model was used to evaluate the results of the model and the model was validated for a period of one year. The accuracy of the constructed model was evaluated as appropriate. In this model, nitrate contaminant was considered as an aquifer contaminant. In order to validate the inherent and special vulnerability of the SINTACS model, the nitrate output of the model was used, The correlation square of the results was about 65%, which shows a good agreement between the two models even thogh the numerical model is considered as micro- model compared to SINTACS one. Considering the role of the aquifer of Varamin plain in supplying the required water of the region, the quantitative and qualitative protection of this aquifer is a necessary and strongly recommonded. Also, in order to reduce the nitrate ion concentration in the study area, long-term solutions such as improving the agricultural structure and cultivation pattern of the area and constructing a collection network and wastewater treatment plant are proposed.

In the present study, the hydraulic characteristics of the flow and the phenomenon of flow hysteresis with the supercritical regime, which can appear in the vicinity of the additional structures in the flow path, such as contracting of the cross-section of the channel, were investigated experimentally. To achieve the objectives of the study, two average diameters of materials inside the gabion basket with sizes of 1.28 and 2.08 cm were used. The inlet flow rate increased in the primary flow and decreased in the secondary flow in the range of 300 to 650 liters per minute. The results of the present study show that by increasing the flow rate and then decreasing the flow, two different behaviors and regimes of flow are observed in the same experimentally conditions. So that with the formation of the phenomenon of hysteresis, the relative depths of the flow were increased by 69.39% and the Froude number of the gabion contraction section has increased significantly by 69.15% and the main cause of the hysteretic behavior of the flow is the current behavior of the flow following its previous behavior. On the other hand, the rate of flow energy dissipation in the use of gabion basket has increased by a relative amount of 71.35% compared to simple contracting. The results also showed that by increasing the size of the constriction and increasing the average diameter of materials in the gabion basket increases energy dissipation and relative downstream depth.

The release rate of non-exchangeable potassium (NEK) plays a significant role in supplying K for plants; particularly in soils containing bearing minerals such as micas and feldespars. No study has been conducted on NEK release kinetics influence of cations in calcareous soils of Chaharmahal and Bakhtiari province. Therefore, the purpose of this study was to investigate the impact of cations calcium and ammonium (from two sources of calcium chloride and ammonium chloride) on kinetics of NEK release in 10 calcareous soils. Soil samples of calcium-saturated were extracted using successive extractions with 0.01 M CaCl2 and NH4Cl solutions for 2-2017 h at 25±1 0C. The results showed that amount of NEK released have a discontinuity in slope at 168 h. Therefore, corves were divided into two segments, including the first stage (2-168 h) and the second stage (168-2017 h). The results showed that released NEK in the studied soils in the first stage, in the 0.01 M Cacl2 and NH4cl extractors were different in the range of 96.50-220.33 and 189.67-549.50, respectively, and in the second stage, in the range of 172.67-391.33, and 320.67-748.0 mg kg-1 respectively. Based on the coefficients of determination (R2) and standard error (SE), the released NEK described in both segment and in both extractors using the zero order, power function, simplified ellovich, and parabolic diffusion equations. Also, the power function equation in both extractants was able to satisfactorily describe the kinetics of NEK release. The kinetics coefficients of the release of NEK were different in the studied soils. the use of multivariate regression equations in both segments and in both extractors of potassium release showed that the NEK release in soils depended NEK concentration, exchangeable potassium concentration and cation exchange capacity of the soil.

There are evidences of the construction of weirs and diversion dams in river bends, and the necessities for building water intakes on both sides of the river bend. The construction of weirs in rivers reaches encounters problems in terms of asymmetry of flow distribution into the intake structures on both sides of the river. The purpose of this study is to investigate the effect of relative curvature on the ratio of the inlet discharge of bilateral water intakes from a weir in a channel bend. The experiments were carried out in three laboratory channels with different relative curvatures (i.e. 3.3, 2.55 and 0.84), which falls into the category of mild, moderate and sharp bends. A broad-crested weir with two types of horizontal and sloping crests was installed at an angle of 60 degrees from the bend inlet. Two intakes were located next to the inner and outer banks. The results indicated that the weir installation in the mild bend performed better uniformity of intake discharges on both channel sides. The performance of sloping crest weir was superior compare with the horizontal crest weir. With the sloping crest weir, average inlet discharge into the inner and outer intakes increased by 8%, 4% and 8%, in three bends of  relative curvatures 3.3, 2.55 and 0.84, respectively, compared to the horizontal crest weir. Considering the sloping crest weir, the discharge ratio of the outer to inner intakes in the three mild, moderate and sharp bends was 1.00, 1.10 and 1.12, respectively. Increasing the channel discharges would result in more uniformity of inflows in the inner and outer banks in the three bends with different relative curvatures.

Estimation of evaporation and transpiration components of maize using by experimental models, is useful for management the water consumption in irrigation. In this research, the amounts of evaporation and transpiration components of maize were modeled for growth stages and salinity stress conditions. Salinity treatments were applied by water with EC of 0.5(S0), 2.1(S1), 3.5(S2), and 5.7(S3)dS.m-1, in the mini-lysimeter. Modeling of maize evapotranspiration components was performed by regression functions of linear, exponential, logarithmic, polynomial and power. Parameters of evapotranspiration (ETc), coefficients of evapotranspiration stress (Ks) and crop growth stage sensitivity (Kpi) were considered as the independent variables and transpiration (T) and evaporation (E) parameters (in separate models) were considered as the dependent variables. The equations coefficients were estimated by SPSS software and the multivariate regression models were generated. From S0 to S3 treatments, the values of evapotranspiration, transpiration and evaporation parameters (in the all of growth period) were measured in the range of 420-307.5, 289-150 and 131-157.5 mm, respectively. Under salinity stress conditions, the maize transpiration was decreased to a more value relative to evapotranspiration. But the evaporation was increased to the same extent. In modeling evaluation, exponential and polynomial models were selected as the optimal models for estimation the transpiration and evaporation rates, respectively. The sensitivity coefficient values (Kp) in four growth stages were equal to 0.556, 0.972, 1.315 and 0.432 (in exponential model) and 1.485, 1.238, 0.447 and 0.816 (in polynomial model). The result of this research was that regression models had an acceptable performance for simulation the evaporation and transpiration components of maize, under salinity stress conditions. Therefore, by estimation the transpiration amount, the crop net water requirement is estimated actually and the water use efficiency increases. Also, by estimation the amount of evaporation losses, the water application efficiency is calculated accurately.

Biochar plays an important role in the optimal use of water in agriculture and improving plant yield and water use efficiency. Therefore, the aim of this study was to investigate the effects of palm leaf and it’s biochar on yield, yield components and water use efficiency of forage corn in a sandy clay loam soil under the same conditions. Experiment with a completely randomized design with two types of modifiers of palm leaf and it’s biochar at six levels (control, 0.5, 1, 2, 3 and 4.5% by weight of date leaf treatments C0, D1, D2, D3, D4, D5, respectively and treatments C0, B1, B2, B3, B4, B5) were performed in three replications as a greenhouse experiment. Characteristics of height, stem diameter, wet and dry weight of shoots, root weight and volume were measured. Water use efficiency base on dry matter yield were calculated. The results showed that the effects of date palm leaves and biochar on the yield and its components, water use efficiency based on the dry matter yield of shoots and roots are significant at the level of 1%. The most effect of biochar and date palm leaf dry matter on shoot dry matter yield has observed in B5, wet plant yield in D2, root dry matter in D1, root volume and stem diameter in B5 and maximum plant height in B1 and B2. Also, the highest water use efficiency of plant is related to B5, which has increased the water use efficiency by 3.6% as compared to the control. It was while D1 improved root water use efficiency. The results showed that use of 4.5% by weight of biochar improved the yield and water use efficiency of the shoot and biochar can be used by increasing the amount of yield and water use efficiency in forage corn by considering its optimal amount.

In hydraulic and river engineering, solid load sediment play an essential role in determining river behavior and morphological control; For this reason, the assessment and correct estimation of  solid load sediment transfport from a long time ago is one of the important issues in the sciences related to river engineering and the environment. The purpose of this study is to estimate the bed load transfer in 19 gravel-bed rivers. For this purpose, first the statistical correlation trend between sediment transport parameter (bed load discharge) and hydraulic and sedimentary parameters (flow discharge, flow depth, flow velocity, the median bed material particle diameter, Froude number,…) is investigated and the bed load discharge is estimated as a univariate regression function. According to the presented results, a favorable correlation was reached between the sediment transport parameter and hydraulic and sedimentary parameters and the results showed that these simple regression relationships in most rivers had acceptable accuracy. Also, the performance of 10 experimental formulas in bed load prediction was investigated. All formulas have had very poor results. For this reason, the parameters related to the formulas that had relatively better results than the other formulas were selected and, in order to increase the estimation accuracy, once again using two kernel-based machine learning methods Support Vector Machine (SVM). Gaussian process regression (GPR) modeling was performed. The results showed that the machine methods have acceptable accuracy in predicting the bed load and the model is related to the parameters of  Begnold formula, which includes the parameters of the stream power, the average flow depth and the median bed material particle diameter, with R =0.923 and NSE =0.851 has the best results in the machine methods.

Estimation of actual evapotranspiration over large areas with appropriate time intervals is important in the optimal management of water resources. The constant need for evapotranspiration data has led to the development of several methods for estimating it. In recent years, the use of remote sensing method to estimate the rate of evapotranspiration in large areas with the desired spatial and temporal resolution has been proposed. In this study, the automatic calibration efficiency of two common mono-source evapotranspiration algorithms estimated from PYSEBAL and METRIC were compared with the results of a drainage lysimeter planted with grass in the Qazvin plain. In this regard, 15 images TM, 22 images ETM+ and 24 images MODIS without cloud and snow during the years 2000 to 2003 were used, which in total 122 outputs were obtained from both algorithms. The results of this study showed that the METRIC algorithm in all three sensors with RMSE (0.42, 0.42 and 1.05 mm / day) respectively had better performance than the PYSEBAL model. Also, the studies performed from the three sensors showed that the MODIS sensor with standard error value (0.15 mm / day) and correlation coefficient (0.98) compared to the two ETM and TM sensors with correlation coefficient values (0.97 and 0.92), standard error (0.17 and 0.59 mm/day) have been able to produce better results. The executive applications of this study can be used to determine the exact amount of evapotranspiration in irrigated lands for water allocation planning, optimization of crop production, irrigation management and assessment of land use change on water effieiency.

In order to investigate the effect of vermicompost and biochar fertilizers on physiological characteristics, growth indices, and grain yield of quinoa in different irrigation frequencies, a split-plot experiment based on randomized complete block design was carried out in the research farm of Kerman in 2020. In this study, the reaction of quinoa (Titicaca cultivar) to three irrigation frequencies (70, 100, and 130 mm from class A evaporation pan) and four organic fertilizers (control, vermicompost, biochar, and vermicompost + biochar) were investigated. The results showed that increasing irrigation frequency significantly reduced the plant height (23.9%), panicle length (17.6%), 1000-seed weight (22.6%), and quinoa grain yield (21.6%). Application of biochar + vermicompost treatment (in equal proportions of 10 tons per hectare) with irrigation frequency of 130 mm from class A evaporation pan increased total chlorophyll (96%) and leaf area index (15.5%) and decreased proline content (48%) compared to control with the same irrigation frequency. In this study, the highest plant height (97 cm), panicle length (15.4 cm), 1000-seed weight (3.141 g), and grain yield (321.94 g/m2) were observed from biochar + vermicompost treatment, which was not significantly different from vermicompost treatment in none of the mentioned traits. In general, it can be concluded that the application of biochar + vermicompost in equal proportions of 10 tons per hectare by increasing the water holding capacity of the soil and also soil nutrients improves the growth and development of quinoa under drought stress.

Magnetic susceptibility (MS) is one of the indices used in soil development evaluation. The aim of this study was to investigate the efficiency of soil magnetic susceptibility in study of soil evolution in the Bandar mountainous landscape of Mazandaran province. In order to achieve the objectives of this study, soil taxonomic classes and morphological index were determined after field studies and physicochemical analysis of 56 soil profiles. Some chemical and geochemical indices were determined and magnetic susceptibility in low (χlf) and high (χhf) frequency were measured by Bartington MS2 dual-frequency sensor on topsoil samples. The correlations between soil magnetic susceptibility and soil taxonomic classes, physicochemical properties, and development indices indicated more efficiency of magnetic susceptibility and morphological index in the representation of soil development in this region. The slope of the study area, as well as the presence of a high amount of carbonates, has caused an inverse relationship between geochemical indices and soil taxonomic classes.

Hashtgerd plain has 56percent of Area of Alborz province and consumes more than 84% of surface water resources and more than 90% of groundwater. It is recognized as one of the most significant agricultural zones that experiences critical crises such as subsidence because of excessive withdrawal of these resources. Consequently, it will be inevitable to manage water resources optimally that establishing the water market as an economic instrument will play a significant role in allocating water resources optimally. The economic value of water input and its demand function was estimated in these areas. The equilibrium price of water input in plain was calculated and compared with the results achieved by valuation calculations using the results of estimating the demand functions and the amount of water supply in this study to examine the probability of developing a water market in Hashtgerd using the positive mathematical planning method and SWAP approach and also the optimal cultivation pattern of the region was estimated, which includes 3divisions.As the result, if there is the required physical infrastructure and the related laws, it will be possible to create a water market among regions in conditions that Nazarabad is the purchaser and Taleghan and Savojbolagh are the sellers of their surplus water resources. The results of examining the possibility of forming an intra-regional water market also show that considering that the enthusiasm to pay in people who have limited resources is more than the obtained equilibrium price and the willingness to receive is lower in people who sell their surplus water resources than the equilibrium price; it will be possible to form a water market among farmers in each city with an equilibrium price equal to 3394 Rials per cubic meter. In this situation, both customers (due to purchasing water cheaper than enthusiasm to pay) and sellers (selling water more expensive than enthusiasm/willing to receive) will benefit from creating the market. However, due to the higher equilibrium price of the economic value of water in the cities of Taleghan and Savojbolagh, there is a possibility of failure of the water market and the transfer of water to other sectors.

Petroleum products are considered to be the most widely used and expensive chemicals in the modern world, but pollution from the extraction and transportation of crude oil has become a global environmental problem. In this experiment, the efficiency of phytoremediation, bioremediation and bio-enhanced phytoremediation in removing crude oil from soil was investigated. For this purpose, a factorial experiment was performed in a completely randomized design with three replications. Factors include three levels of soil oil pollution (zero, 4 and 8% by weight), four plant treatments (without plants, bermudagras (Cynodon dactylon), sorghum (Bicolor Sorghum) and barley (Hordeum vulgare)) and three bacterial treatments (without bacteria). Were native bacteria (Brachybacterium muris) and non-native bacteria (Pseudomonas putida). The results showed that the percentage of crude oil removal by plant cultivation, soil inoculation with bacteria and combined application of plant and bacteria increased significantly compared to the control. Plant culture was more effective than bacterial inoculation in reducing the concentration of petroleum products and the efficiency of bacteria increased significantly with plant culture. At each level of contamination, the highest percentage of oil removal was observed with the combined application of sorghum and Brachybacterium muris. In all plant treatments, the highest oil removal percentage was measured at 4% oil pollution and Brachybacterium muris inoculation. Oil pollution significantly reduced leaf dry weight and chlorophyll concentration, but the use of bacteria (especially native bacteria) significantly reduced the negative effects of oil pollution on plants compared to non-inoculation treatments. Oil pollution increased the proline concentration in the leaves of plants and decreased the proline concentration with the use of native bacteria. Establishment of plant with microorganisms can be considered as a key component of the strategy to remove hydrocarbons. Consequently, these bacterial and plant species can be used for the biodegradation of soils contaminated with crude oil.

Predicting the flow behavior in the arch of meandering compound channels has a great importance in coastal protection programs (sediment transport and deposit pattern), pollution propagation and flood control. Therefore; the hydrodynamics of the flow in the composite-meander channel with a constant sinuosity factor 1.3, and at two relative depths 0.3 and 0.55 were investigated using a laboratory model. Due to the three-dimensional structure of the flow in the channel bend, the data were analyzed in seven cross sections with angles of zero, 30 and 60 degrees to the vertices of the bending apex using an ADV velocity-meter in lattice plates with dimensions 3*3 cm2 and perpendicular to the flow. The results showed that the gradient of three components of velocity at relative depths 0.3 are greater than 0.55 which shows more vortex power and intensity of turbulence in less amount of relative depth. average velocity ratio on the outer beach of the floodplain to the average velocity of the whole section, similar to the inner beach, has been a function of the relative depth of the flow, and is less and more than one, respectively. For this reason, the flow in the outer floodplain, unlike the inner floodplain, has a reducing effect on the flow velocity in the main channel. Also, as the relative depth increases from 0.3 to 0.55, the ratio of the average flow velocity in the main channel to the total average velocity decreases and approaches one. Reynolds stress () had maximum and positive values near the main channel bed, and by moving away from the bed, it has reached a negative value and it shows its minimum amount near the flow surface. The value of this local parameter also increases at the edge of floodplains.

The use of iron (Fe) fertilizers is the most effective methods to deal with Fe deficiency in calcareous soils for agricultural purposes. Use of cheaper and available resources has been the focus of researchers. In this study, the effect of different sources of Fe fertilizer on the availability of Fe in soybean in a completely randomized design with factorial arrangement including three factors of different sources of Fe fertilizer (zero, Fe-sequestrin, Fe-sulfate and Fe-oxide with concentrations of 5, 30 and 50 mg of Fe per kg of soil, respectively), decomposed cow manure (0.5 and 1.5% by weight) and elemental sulfur in the presence of Thiobacillus bacteria (zero and 25 mg kg-1 and thiobacillus 1.8% of sulfur) in three replications. In 2019, it was studied in the research greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad.The results showed that concentration and absorption of Fe in shoots in fertilizer treatments was higher than that in the control. Application of iron oxide alone, with manure, with sulfur and application of iron oxide with manure and sulfur could make a significant difference in increasing the concentration and absorption of Fe with other treatments. Use of iron oxide increased iron concentration by 1.24, 1.36 and 1.69 times and Fe uptake by 1.11, 1.28 and 1.73 times compared to sequestrin, iron sulfate and iron oxide treatments in shoots of soybean in the shoots. Application of ferrous sulfate alone did not differ significantly in increasing the concentration and absorption of Fe compared to treatments of ferrous sulfate with manure and with sulfur. In addition, no significant difference was observed between Fe uptake in sequestrin alone and manure. According to the results, to increase the efficiency of iron oxide, it is recommended to use it with manure and sulfur as a suitable alternative.