JWSS - Journal of Water and Soil Science

The investigation of local scour below hydraulic structures is so complex that makes it difficult to establish a general model to provide an accurate estimation for the local scour dimension. During the last decades, Data Driven Methods (DDM) have  been used extensively in the modeling and prediction of unknown or complex behaviors of systems One of these methods is Group Method of Data Handling (GMDH), that is a self-organization approach and increasingly produces a  complex model during the performance evaluation of  the input and output data sets. So, the objective of this study was to investigate the potential of the GMDH method in the accurate estimation of local scouring geometry (maximum scour depth, the distance of maximum local scour depth till Ski-jump bucket and length of local scour) below the Siphon spillway with Ski-jump bucket energy dissipaters for a set of experimental data. 80% of data set was used for the training period and the remaining data set was used for the test period. The average values of MSRE, MPRE, CE and RB for the nonlinear second order transfer function (FUNC1) were calculated to be 0.92, 0.02, 8.74, -0.01; also, for the nonlinear first order transfer function (FUNC2), they were 0.85, 0.02, 10.43 and -0.02, respectively. The results indicated that the performance of FUNC1 was better than FUNC2. Also, the value of the coefficient of determination (R2) for the estimation of local scour dimension using different methods such as s linear regression, nonlinear regression and ANN indicated the high performance of the developed model of GMDH in the accurate estimation for local scour dimensions.

This study was done to evaluate the effect of topography, water table, and irrigation on gypsc soil development and clay mineral diversity in Ram-Hormuz Plain, Khuzestan Province. To localize, 10 profiles in this region that covered all purpose irrigation and topography situation were described. The results showed that the soils could be classified in Entisols, Inceptisols and Aridisols orders. All soil epipedons were ochric and subsurface horizons were cambic, gypsic, and salic. The salic horizons were formed under a low water table. The XRD results showed that smectite, kaolinite, illite, chlorite, palygorskite, vermiculite and sepiolite were the dominant minerals, respectively. Kaolinite and illite were inherited from the parent material, but chlorite was the result of both inheritance and transformation of other clay minerals except uncultivated or non-irrigated soils. Sepiolite was decreased in gypsic horizons, but palygorskite was increased in these horizons. Sepiolite was raised with increasing the depth under the good drainage class; this could be related to neoformation, but it was decreased with depth under the weak drainage class. These results could be due to the instability of this mineral in high moisture and its low Mg activity. There was also a negative correlation correlation between Palygorskite and smectite; this was such that most palygorskite was observed in the surface horizons, but smectite was in the subsurface. Smectite was the dominant clay mineral in the studied soils; it was formed from the weathering of other minerals as well as from neoformed ones in the lowlands. Vermiculite was formed in these soils due to k depletion by leaching or plant absorption. This happened in the illite to smectite transformation process. Therefore, topography and irrigation could be regarded as the main factors putting these soils in high category; also, clay mineral assemblage was different under this situation in these soils.

Due to the lack of necessary equipment for measuring and recording changes in watershed runoff and flood situation after the implementation of corrective actions, using hydrologic models is considered as an efficient tool to assess the undertaken actions and simulate the behavior of the watershed before and after the implementation of these measures. The present study aimed to simulate the effects of corrective actions on runoff components using HEC- HMS hydrological models in the form of a rangeland and watershed plan in 2006 and the predicting plan of applicable operations in a region in the Meikhoran watershed, Kermanshah. For this purpose, three scenarios including the conditions before running the rangeland and watershed plan, the conditions after running the project and requirements and enforcement actions resulting from the proposed location map were considered in the spring of 2006. First, a map of the curve number (CN) changes was prepared under all three scenarios caused by the vegetation changes and by implementing HEC-HMS model, the curve number criteria, the peak discharge and flood volume were determined to assess the changes in hydrological basins and their values for all three scenarios were calculated and compared. The results showed that the HEC- HMS model for the base period (first scenario) with Nash-Sutcliffe coefficient 0/551 and the coefficient of determination 0/63 had an acceptable accuracy in predicting runoff. Nash-Sutcliffe coefficient for the second and third scenarios was 766/0 and 0/777, respectively. Also, the results showed that in the second scenario,  there was an 8/85 and 7/74% decrease in the peak flows and runoff volumes, respectively,  and these values for the proposed operation were estimated to be 12.84% and 6.33%, respectively. Overall, the results indicated the considerable impact of rangelands and watershed management (third scenario) on the reduction of effective runoff components, particularly flood peak, on the basis of the location model.

In this study, the performance of slot in the spur dike was evaluated as a way to reduce the scouring around the installed flat spur dike in a 180 degree bend and the development of scouring in the slotted spur dike was compared with that of the spur dike with no slot. To evaluate the effect of the slot on the development of scouring around it, a flat spur dike made of Plax Glass was installed in a position of 70 degrees from a bend (180 degrees) in the flume bed. After determining the maximum of scouring depth at the tip, to reduce the scouring around the spur dike, two slots with the determined height were placed in 4 different positions in the spur dike. Experiments with 4 different discharges and constant flow depth in clear water conditions were conducted. The results of the experiments showed that the created the slot reduced the scouring depth toward the spur dike. In both slots, the minimum of scouring depth was seen in a model with the closest position of the slot toward tip, and its maximum was seen in a model with the farthest position from the slot.

Sugarcane is cultivated in the wide area in Khuzestan province. In these areas, irrigated sugarcane cultivation consumes more than 30,000 cubic meters per hectare annually. This research was carried out to determine the effect of sugarcane cultivation on the soil development process and forms of iron oxides. Different sugarcane fields with different utilization times were selected and soil physico-chemical properties and different Fe forms were measured. The results showed that with enhancing the utilization time, the total amount of total iron oxides (Fe_d) and crystalline iron oxides (Fe_d-Fe_o) was increased. The average value of the Fe_d from 6958 mg/kg in the fields with a medium utilization history was decreased to 4560 mg/kg in fields with a short utilization history. Similarly, the average amount of crystalline iron oxide from 5888.3 mg/kg in the fields with a long utilization history was decreased to 5003.9 mg/kg in the fields with a short utilization hostory. This increase reflected the effect of sugarcane cultivation on the soil development process in the cultivated fields. The amount of non-crystalline iron oxides (Fe_o) was decreased from 443.9 mg/kg from the soil surface to 273.8 mg/kg to the subsurface. This increase was related to the more organic matter and the microbial activity in the surface soil. The amount of active iron (Fe_o/Fe_d) was dropped in all fields after the cultivation. Also, this ratio was dropped from 0.055 in the fields with a long cultivation history to 0.064 in the fields with a short utilized field. The results, therefore, showed that the increase of crystalline iron oxides was due to sugarcane and its heavy irrigation.

Landscapes are considered as a series of different land units with a size, shape and location arrangement that are permanently under the influence of natural events and human activities. Understanding the dynamics and heterogeneity of landscapes and environmental changes is of great importance. In order to quantitatively analyze and interpret the factors affecting the changes in the environment and terrain diversity, diversity indices were used to analyze the ecosystem. In this study, the relationships between soils evolution and geomorphic surfaces were investigated by applying pedodiversity indices in a part of a semi-arid region of Chaharmahal-Va-Bakhtiyari Province. In the studied area, three orders were recognized: Mollisols, Inceptisols, and Entisols. The results showed that soil evolution in the studied area was mostly influenced by topography, parent material and the underground water level; that is, in the higher lands, the lowest evolution was observed while in the plain ones, the soil of the higher evolution observed. In addition, the effect of geomorphic surfaces were obvious. Pedodiversity indices increased under the decrease of the hierarchy levels. In addition, the obtained equations revealed the nonlinear relationships in the area of geomorphic surfaces. The positive and nonlinear relationship between pedodiversity indices confirmed the nonlinear dynamic system in the studied soils.

The aim of this study was the effect of raw water quality on the efficiency of domestic reverse osmosis apparatus in Khuzestan province. The results showed that the purified water quality was related to the quality of entrance raw water. With increasing in salt concentrations (EC) or TDS, purification efficiency was decreased. The cation and anions content of refinery water was related to TDS and EC. The Ca/Na and Mg/Na were decreased due to refinery. The ability of these apparatus to reduction of two valence cations were more than mono valence. As same as this trend was observed for anions. Also, the comparison of the EC of raw water and refinery from these apparatuses had different EC from different raw water entrance. This means of these apparatuses had different efficiency with changes of raw water quality. Generally, domestic water purification systems have better performance in Karun river water treatment than in Kheiryrabad and Karkheh rivers.

Soil moisture is one of the most important factors that can affect productivity in ecosystems in arid and semiarid regions. The aim of this study was to investigate soil moisture and vegetation changes in the Isfahan province at the seasonal scale. For this purpose, MODIS Land Surface Temperature (LST) and NDVI data were used to calculate the TVDI index, and the rate of soil moisture content was also measured at several soil depths including 5, 10, 20, 30 cm. in the growing season. Seasonal changes of LST and NDVI indices were also studied in different climate regions ranging from humid to hyperarid. The results showed that the changes in NDVI and LST in this region were different, depending on the climate type and soil conditions; the LST and its changes mostly depended on the amount of vegetation cover NDVI changes based on the plant phenology in humid regions, which was were greater than that in arid and semi-arid climates. Soil moisture monitoring indicated that the relationships between TDVI and different soil depths varied based on the seasonal conditions. In the early growing season, the soil moisture at the depth of 0-5 cm had a higher correlation with TVDI, but in the middle of growing season, the deeper soil moisture (10-30 cm) showed the highest correlation. Therefore, the findings of this research indicated the importance of the growing season, soil conditions and vegetation percentage and types in the soil moisture studies by using satellite data.

The production of compost and vermicompost from manure and different organic residues and also, their enrichment with some fertilizers and other treatments have been extensively investigated. However, no study has yet been conducted on the enrichment of composted and vermicomposted manure with clay minerals. This research was, therefore, carried out to investigate the selected properties of phlogopite enriched manure during the composting process with and without earthworm activity. The experiment was conducted in plastic containers with the lid under an average temperature of 27.5°C and the humidity of 42.5% using a factorial arrangement in a completely randomized design with 3 replications. Factors included levels of phlogopite addition (0%, 20% and 40% by weight), with or without the earthworm Eisenia fetida for different time periods of 1.5, 3, 4.5 and 6 months. At the end of the experiment, the total of organic carbon, nitrogen, potassium, magnesium, and iron, as well as the contraction the available magnesium, potassium and iron, was determined. The results showed that the percent of organic carbon was decreased while the total nitrogen, the total and available potassium, iron and magnesium were increased with time. The results also indicated that a significant percentage of the total content of the elements in all treatments without phlogopite was available. However, in treatments containing phlogopite, the amount of the available elements was increased slowly with time. This was Due to the weathering of phlogopite mineral and the decomposition of manure. In general, it seems that the enrichment of composted and vermicomposed manure with phlogopite can guarantee the supply of nutrients such as potassium, iron and magnesium in a longer period, as compared with the ordinary composts.

In order to investigate the effect of the type drip of irrigation methods, subsurface irrigation and furrow irrigation on the domestication of Hedysarum criniferum Boiss., an experiment with a  randomized complete block design with three replications was implemented  at Isfahan University of Technology for two years (2016 to 2018) . For this purpose, clay pipes were made and the plant was cultivated on the sides of clay pipes and types. Also, furrow irrigation treatment was applied as the control. During the experiment, all treatments received the same water and finally, some growth parameters were measured. The results of the study showed improvement in height (0.43 and 0.34), canopy cover (0.66 and 0.52), stem number (0.44 and 0.85), chlorophyll index (0.45 and 0.45), seed emergence (0.75 and 0.30), plant survival (0.78 and 0.55), yield (0.23 and 0.35), and water use efficiency (0.25 and 0.25) under type drip irrigation treatment, as compared to subsurface and furrow irrigation, respectively (P<0.05). In general, the type drip treatment is recommended in the early years of planting; however, since the maximum production potential of this plant is in the third year onwards, it is necessary to examine the results in the following years to recommend the proper irrigation method, especially the use of subsurface irrigation. 

Characteristics of most soils in arid and semi-arid regions affected by carbonates. The study aimed to determine the distribution of carbonates in the size components of some soils in Khuzestan province. Upward to the bottom of Karun, Karkheh, and Jarahi rivers were studied at depths of 0-50, 50-100, and 150-100 cm. The results showed that the average amount of carbonates in the soils of the Jarahi river basin (37%) was significantly different from the amount in the soils of the other two rivers (33%). Carbonates were observed in all soil size components but the maximum was present in the clay component. The highest regression relationship between soil particles was in the clay component (0.375). The highest percentage of particle reduction after carbonate removal was related to coarse silt particles (0.75). Therefore, the soil texture changed from clay in Jarahi, from clay and silty clay in Karun, and silty clay in Karkheh due to the removal of carbonates to sandy loam. There was no significant difference in the distribution of carbonates at different depths for river soils and all studied soils. The relatively uniform distribution of carbonates in the four components studied in these soils from the surface to the depth showed that the carbonates originated from the parent material, namely alluvial flood sediments of these rivers.

The southern regions of Kerman Province have repeatedly encountered dust storms. Therefore, the objective of this study was to identify dust sources using effective parameters such as vegetation cover, land surface temperature, soil moisture, soil texture, and slope as well as to detect dust storms originating from these regions based on 31 MODIS images in 2016 and SRTM data. After normalizing parameters, the dust source map was prepared by fuzzy logic and assessed with an error matrix and available dust source map. Results showed that 30.5% of the study area was classified as a low source of dust, 39.55% as moderate, and 29.85% as severe-very severe. The overall accuracy of the produced map was about 70% and the producer and user accuracy of the severe-very severe class was more than 87%. The detection of dust storms originated from the identified dust sources also confirmed a crisis situation in the region. Due to the repeatability and continuity of obtained dust source map at pixel scale, it can be used to update available dust source maps and manage dust crisis in the region, properly.

Iran is located in the dry belt of the earth and is predicted to face water stress in the next half-century. Currently, the area of sugarcane cultivation in Khuzestan is over 85,000 hectares and due to the high water needs of sugarcane and drought conditions, optimization of water consumption and irrigation management is necessary to continue production. Therefore, in this study, the values of soil moisture, canopy cover, biomass yield in five treatments and irrigation levels (start of irrigation at 40%, 50%, 60%, 70%, and 80% soil moisture discharge) during 2 planting dates in the crop year 2015-2016 on sugarcane cultivar CP69-1062 in Amirkabir sugarcane cultivation and industry located in the south of Khuzestan was simulated by AquaCrop model. The measured data on the first culture date (D1) and the second culture date (D2) were used to calibrate and validate the model.  The results of NRMSE statistics in canopy cover simulation in calibration and validation sets with values of 2.1 to 15.6% and 3.8 to 18.3%, respectively, and in biomass simulation with values of 6.2 to 15.2%, and 9.5 to 12.6%, respectively and coefficient of determination (R2), range 0.98 to 0.99 indicated that the high ability of the AquaCrop model in simulation canopy cover and biomass yield. whereas, the values of NRMSE of soil depth moisture in the calibration and validation sets ranged from 11.6 to 23.8, and 12.2 to 22.7, respectively, with a coefficient of determination (R2), 0.73 to 0.96 (calibration) 0.8 to 0.93 (validation) showed less accuracy of the model in the simulation. The best scenario is related to the third proposal that water consumption, water use efficiency, and yield are 1710 mm, 1.53, and 42.27 tons per hectare, respectively, which shows a reduction in water consumption of 360 mm.

The objective of the present study was to investigate the performance of some of the extracted information for mapping land degradation using remote sensing and field data in Fras province. Maps of vegetation cover, net primary production, land use, surface slope, water erosion, and surface runoff indicators were extracted from MOD13A3, MOD17A3, Landsat TM, SRTM, ICONA model, and SCS model, respectively. The rain use efficiency index was obtained from the net primary production and rainfall map, which was calculated from meteorological stations. The final land degradation map was prepared by integrating all the mentioned indicators using the weighted overlay method. According to the ICONA model, 5.1, 9, 47.21, 27.91, and 10.73 percent of the study area were classified as very low, low, moderate, severe, and very severe water erosion; respectively. Overlaying the ICONA map with other indicators showed that very high and high classes, moderate, and low and very low classes of land degradation covered 1.3, 18.7, 70, 0.9, and 9.1 percent of the study area, respectively. According to the results, integrating remote sensing with ICONA and SCS models increases the ability to identify land degradation.

Drought is one of the most complex natural disasters due to its slow onset and long-term impact. Today, the use of remote sensing techniques and satellite imagery has been considered a useful tool for monitoring agricultural drought. The objective of the present study was to evaluate spatial and temporal monitoring of agricultural drought in the lake Urmia catchment area with the ETDI drought index which is calculated from Nova satellite images based on actual evapotranspiration from the SEBS algorithm and compared with the ground index SPI. For this purpose, 248 AVHRR sensor images and NOAA satellites during the statistical period of 1998-2000 and 17 meteorological stations with a statistical period of 30 years were used to calculate the indicators. To determine agricultural lands, six thousand points were marked for different uses and their actual evapotranspiration was calculated using the SEBS algorithm. The results showed that with the onset of the drought period in 1998, the ETDI index indicated 9.4% in weak drought conditions in May and 90.6% in normal conditions. Over time, in June of 1998, the situation was different with 95% in a weak drought situation and 5% in a normal situation for the city of Tabriz. In July, the entire catchment area experiences a slight drought. Then, in August, 84% of the basin is in normal condition and 16% in Tabriz and Urmia are declared weak drought. It was also founded that the ETDI drought index due to the combination of visible and infrared bands and its combination with terrestrial data has a physical meaning and has high certainty and predicts drought faster and more accurately.

Due to the climatic conditions of Iran, increasing water scarcity, and the effect of drought stress on the efficiency of irrigation water consumption and chemical fertilizers application, an experiment was conducted to investigate the effect of irrigation intervals (6, 9, and 12-day intervals), different levels of nitrogen fertilizer (200, 300, and 400 kg urea per hectare) and cultivation methods (on-ridge or heeling up and in-furrow) on yield and productivity of sugarcane as a factorial design based on randomized complete block design in 3 replications at Hakim Farabi Agro-Industry Company in Khuzestan province. The results showed that the maximum (106.73 tons/ha) and minimum (59.10 tons/ha) sugarcane yields were observed in 9-day and 12-day irrigation intervals, respectively. Also, the highest sugarcane yield (99.89 tons per hectare) was obtained in the treatment of 400 kg urea per hectare and the in-furrow planting method resulted in a higher yield compared to the on-ridge planting method. The highest water productivity in sugarcane stem yield and sugar production with 3.55 and 0.34 kg per cubic meter of applied water, respectively, was obtained in a 9-day irrigation interval. A significant increase in water use efficiency in sugarcane stem yield was observed in 400 kg urea/ha compared to the other two fertilizer levels. However, there was no significant difference in water productivity of sugar yield between different fertilizer treatments. The results showed that 6 and 9-day irrigation intervals in most of the studied traits were not significantly different. Therefore, using a 9-day irrigation interval is suggested in the studied area when the sugarcane cultivation area is high and the amount of available water is limited. In-furrow planting method can also be effective in reducing water consumption. Therefore, deficit irrigation and proper nitrogen fertilizer consumption can be very effective in sugarcane cultivation.

The ability of remote sensing (RS) in irrigation scheduling has been accepted in the world due to the collection of data on a large scale and the determination of water stress indicators with greater speed and less cost. Crop Water Stress Index (CWSI) and Water Deficit Index (WDI) are components of the most recognized water stress indices. Despite the accuracy and precision of the CWSI index that has been proven in plant irrigation scheduling, the lack of complete density of vegetation, especially in the early stages of growth, is one of the most important defects of using this method in crop irrigation scheduling. While estimating the water deficit index using remote sensing technology does not have these limitations. An experiment was performed in the crop year 98-99 in the city of Karaj to check the accuracy of this index. The amount of WDI and CWSI in a wheat field with optimized irrigation management was determined and compared and evaluated using statistical parameters. The results showed that the coefficient of explanation between these two indicators in the months of April, May, and June is 0.77, 0.85, and 0.71, respectively.