Showing 886 results for SH
F. Afsharipour, M.r. Sharifi, A. Motamedi,
Volume 28, Issue 4 (Winter 2024)
Abstract
Drought monitoring in snowy basins requires modifications in common drought indices, called snow drought indices. The latest developed snow index is SZIsnow. The SZIsnow index calculating with special algorithm requires access to the values of 22 different climatic and physical variables, including soil moisture at a depth of 0 to 10 centimeters, soil moisture at a depth of 100 to 200 centimeters, air temperature, water equivalent to snow, runoff from snow melting, snowfall, rainfall, total precipitation rate, evaporation and transpiration, wind speed, surface runoff, groundwater runoff, potential evaporation, air pressure, relative humidity, net latent heat flux, ground heat flux, net sensible heat flux, evaporation from bare soil, evaporation from the canopy, and potential evapotranspiration. So far, the mentioned index has been calculated only on a continental scale. Drought monitoring at the basin scale is important as one of the management aspects of water resources. On the other hand, due to the lack of sufficient information to estimate the mentioned parameters, the use of information from global databases will be a solution. Therefore, in this research, while introducing the process of calculating the SZIsnow index, in the Dez catchment area, extracting the required parameters of the index in a time scale of 3, 6, and 12 months and a period of 41 years (1982 to 2023) using data GLDAS and then drought monitoring of the basin was studied. The results showed that the new SZIsnow index is a multi-variable index that provides the possibility of calculating the index due to the existence of parameters that lack ground observations and on the other hand, the availability of the reliable GLDAS database. Also, the results showed that in the time steps of 3, 6, and 12 months, July at -0.59, June at -0.45, and October at -0.35 had the highest amount of drought, respectively.
A. Keshavarz, R. Modarres, S.a.r. Gohari,
Volume 28, Issue 4 (Winter 2024)
Abstract
This study was conducted to present rangeland bioclimatic zoning for Iran based on the changes in the power spectrum of the average monthly Net Primary Production (NPP) of the rangelands of Iran. Fluctuations of the mean monthly power spectrum of the NPP signal of rangelands of Iran from 2000 to 2022 were analyzed using the Power Spectrum Density (PSD) method in the frequency band between 0-100 Hz. In 24 bioclimatic subzones, there are four common periods in all sites at frequencies of 0 (no change is repeated), 8.34 (3.59 days), 16.66 (1.80 days), and 25 (1.2 days) Hz observed, which shows that the major data changes occur in those periods and that the NPP changes of Iranian rangeland are more influenced by global and regional effects than local effects. The maximum power of these spectra is concentrated in high time scales. Therefore, cycles with lower frequency (higher time scale) are more important than cycles with higher frequency (shorter time scale) and show that the changes of NPP in Iranian rangelands have long-duration cycles under climate fluctuations. In the present research, Iran was classified into 5+1 rangeland bioclimatic zones using the results of the monthly mean power spectrum of the NPP signal of rangelands, the Wards clustering method, and the Euclidean square distance. It seems that this method provides a proper match between biological boundaries and climate. Pearson correlation coefficient was used to investigate the coherence of rangeland bioclimatic regions within each homogeneous group. Correlation results showed a significant spectral density similarity within groups at the significance level of 0.01% between rangeland bioclimatic regions, especially in the second and fifth clusters.
M. Niroubakhsh, A.r. Masjedi, M. Heidarnejad, A. Bordbar,
Volume 28, Issue 4 (Winter 2024)
Abstract
The application of flip bucket and triangular launchers with different shapes has been given more attention due to safety and better energy consumption to protect the downstream bed of water structures, as well as economic benefits compared to other energy consumers. The objective of this research was to investigate the energy loss of the passing flow in the dentated flip bucket and dentated triangular sill spillways in laboratory and numerical conditions. Physical and numerical modeling was used in a rectangular flume with a length of 9 meters, a width of 0.5 meters, and a height of 0.5 meters, flip bucket, and triangular spillways with dentated with specific dimensions according to the USBR standard in different discharges intensities in laboratory and numerical conditions. The amount of energy loss in the dentated flip bucket spillway was 71.4% and the dentated triangular sill spillway was 74.8% in laboratory conditions, which showed that the dentated triangular sill spillway has a better performance in terms of energy loss than the flip bucket and triangular spillway. The results showed that the shape of the spillway geometry and the presence of the dentated at the end of the structure is an important and influential factor in the amount of energy loss of the currents passing through the dentated flip bucket and dentated triangular sill spillways, which causes more broken and compressed flow lines and, as a result, an increase in speed at the moment. The launch and finally the relative loss of energy is more downstream of the structure. After determining the better performance of the dentated triangular sill spillway in energy loss, the numerical simulation of the dentated triangular sill spillway was performed using the numerical calculation method in Flow-3D software. The results of the analyses indicated that the amount of energy loss in the dentated triangular sill spillway in the numerical calculations was 87.5%, which showed the alignment and correctness of the tests performed with the laboratory conditions.
E. Jafari Nodoushan, A. Shirzadi,
Volume 28, Issue 4 (Winter 2024)
Abstract
The rapid and complex movement of sediments in rivers and coastal areas with highly erosive and unsteady flows presents river engineers with numerous problems in the geomorphology of alluvial rivers. Accurately predicting these complex processes in the water-sediment system (a multiphase, dense, granular flow system) is still a major challenge for mesh-based models. Due to the ability of meshless Lagrangian methods to model large deformations and discontinuities, meshless Lagrangian methods can provide a unique way to deal with this complexity. In the current research, the capabilities of the weakly compressibility moving particle semi-implicit (WC-MPS) model in soil-fluid interaction modeling are developed to enable the modeling of sediment transport and erosion effects behind coastal walls. In this method, granular material is considered a non-Newtonian and viscoplastic fluid. The 𝜇(I) rheological model has been used to predict the non-Newtonian behavior of the granular phase. To verify the application of the present model in simulating the interaction of liquid and solid phases, first, the widely used problem of dam break on an erodible bed was modeled. The NRMSE model was calculated to be approximately 6%, which indicates the efficiency and accuracy of the target model in this problem. At the end, the scouring of coastal walls was simulated by the WC-MPS method using 𝜇(I) rheology model. Investigations show that the processes related to erosion and scouring can be well modeled using the current Lagrangian method. The numerical results show excellent agreement with the laboratory measurements. It should be noted that the mean error of the mentioned model is estimated to be 10%.
R. Daneshfaraz, M. Majedi Asl, T. Omidpour Alavian,
Volume 29, Issue 1 (Spring 2025)
Abstract
Weirs play a crucial role in flood management and dam safety, accounting for a significant portion of the construction costs of dams. The selection of floods with long return periods for flood design is of utmost importance. However, in some cases, increasing the weir capacity by widening it may be impossible due to topographical limitations. One solution to enhance the flow capacity of weirs is the application of labyrinth weirs. These weirs increase the effective length of the weir crest within a given width, allowing for the passage of higher flow rates while maintaining similar hydraulic conditions. In this study, the hydraulic performance of labyrinth weirs is investigated using the Flow3D numerical model and laboratory data. Since laboratory experiments are time-consuming and costly, employing numerical simulations to achieve more accurate and reliable results for evaluating the hydraulic behavior of labyrinth weirs is prioritized. The results of the simulations indicate that the Flow3D software, utilizing statistical parameters such as R², DC, and RMSE, achieves values of (0.9805, 0.9725, and 0.0142), respectively. This demonstrates its capability to model the flow passing through weirs with high accuracy. The obtained values of the discharge coefficient in Flow3D show a high agreement with the laboratory data from Crookston. The approximate alignment of these results indicates the high accuracy of the numerical model. Additionally, in comparison to different discharges, the relative computational error observed for flow rates of 0.35, 0.6, and 0.44 (cubic meters per second) was approximately 0.5 percent, while for flow rates of 0.3, 0.4, and 0.57, the corresponding errors were 8, 6, and 4 percent, respectively. The results indicate that these tools can be effectively utilized in precise hydraulic analyses and the optimization of weir designs, irrigation systems, and fluid dynamics phenomena.
S. Ashkevari, S. Janatrostami, A. Ashrafzadeh,
Volume 29, Issue 1 (Spring 2025)
Abstract
In this study, a conceptual model based on dynamic systems was developed to optimize the management of water, land, and agricultural production (tea and rice) in the irrigation zones of the Sefidroud irrigation and drainage network. To understand the behavior of the network and create a simulation model of the system, a dynamic systems modeling approach was employed, and the simulation was conducted using MATLAB/Simulink. Subsequently, the optimization model of the studied system was developed as a multi-objective model using a genetic algorithm. Various management scenarios were implemented through the weighting of the objective functions. The results showed that selecting the best response from multi-objective optimization models depends on the weighted values of the objective functions, and by changing these values, decision-makers can provide various responses to complex optimization problems. The optimization model determines the cultivated area and water allocation in such a way as to minimize water scarcity and maximize crop performance through different weighting combinations. Furthermore, the findings indicate that the canals of the irrigation network play a crucial role in meeting water needs, and equitable water allocation is essential to prevent excessive extraction and negative consequences, such as saline intrusion and land subsidence. The study demonstrates that the best solutions are contingent upon local conditions and decision-makers' policies. To achieve maximum economic benefits and address water needs, it is suggested to use a weighting combination close to (w1=1,w2=2). Ultimately, this model assists managers and decision-makers in minimizing water scarcity in the region by adjusting cropping levels and optimizing the use of available water resources.
J. Karimi Shiasi, F. Fotouhi Firoozabad, A. Fathzadeh, M. Hayatzadeh, M. Shirmardi,
Volume 29, Issue 1 (Spring 2025)
Abstract
One of the main factors contributing to water erosion is the inherent characteristic of soil erodibility. Erodibility depends on particle size distribution, organic matter, structure, and soil permeability. This research aimed to investigate changes in the soil erodibility factor across geomorphological facies. The soil erodibility index was estimated by sampling 58 points within the geomorphological facies of the Dorahan watershed, using the Wischmeyer and Smith method. In the laboratory, soil granularity distribution, organic matter, soil structure, the amount of gravel, lime, salinity, acidity, and sodium absorption ratio were measured. Results indicated that soil erodibility across the entire area ranges from 0.0148 to 0.0661 (t.hr/Mj.mm). The soil erodibility index (K) for the hro-p1 and hro-p2 facies is higher than for others and exhibits the widest range of variations compared to the other facies. The lowest range of changes within geomorphological facies is associated with the hrc facies. The erodibility index decreases from the east to the west of the basin due to the presence of exposed rock faces, which protect the soil as a cover layer.
Sh. Amiri, B. Khalili,
Volume 29, Issue 1 (Spring 2025)
Abstract
Soils are continuously exposed to large amounts of engineered nanoparticles, particularly silver nanoparticles (AgNPs), which can affect soil microbial activities and nitrogen cycling. The hypotheses of the present study were: (i) vegetation types would differ in their responses to Ag types and concentrations, (ii) these responses would be linked to changes in soil protein and amino acid concentrations, and (iii) combined plant root systems alongside Ag types and concentrations would have offsetting effects on soil protein and amino acid concentrations. A greenhouse experiment was conducted to test these hypotheses using a factorial arrangement of treatments within a randomized block design. Two soil types with loamy sand and sandy loam textures were collected from agricultural fields in Isfahan, specifically from the Badroud (33◦ 44′ 50" N, 51◦ 57′ 55" E) and Femi (33◦ 42′ 17" N, 51◦ 59′58" E) regions. The treatments included: 1) soil types (loamy sand and sandy loam), 2) root systems (non-planted, wheat, and safflower), 3) Ag types (no Ag added, AgNPs, and AgNO3), and 4) Ag concentrations (50 and 100 ppm). The plants were harvested 110 days after sowing, with soil samples collected from both the root zone and non-planted soil, after which the concentrations of protein and amino acids were measured. In the Badroud soil, protein concentration significantly decreased (p < 0.05) with increasing depth. Although depth changes did not show a significant difference in protein concentration in the soil under wheat cultivation, increasing depth resulted in a significant decrease (p < 0.05) in protein concentration in the soil under safflower cultivation. In the Fami soil, the addition of silver nitrate led to a significant (p < 0.05) increase in protein concentration, despite the fact that the addition of silver nanoparticles had no significant (p < 0.05) effect on soil protein concentration. In the Badroud soil, the highest concentration of soil amino acids was observed in the silver nitrate treatment, while the silver nanoparticle treatment did not significantly affect soil amino acid concentrations (p < 0.05). However, applying silver treatments at both tested concentrations resulted in a significant increase (p < 0.05) in soil amino acid levels. Overall, the effects of nanoparticles varied depending on the measured parameters (protein or amino acid), soil texture, and type of cultivation. Further studies are needed to determine the mechanisms by which AgNPs and AgNO3 affect the soil nitrogen cycle in the presence of plants at different soil depths.
A. Mirzaei, A. Soltani, F. Abbasi, E. Zeinali, Sh. Mirkarimi,
Volume 29, Issue 1 (Spring 2025)
Abstract
Water scarcity and adaptation to it are the most significant issues facing Iran's agriculture. Optimizing the cropping pattern is one of the fundamental strategies for addressing water scarcity. This study evaluated the optimization of the cropping pattern in the irrigated lands of Fars province, one of Iran's key agricultural production areas. Linear mathematical programming and the SAWA system (System for Provincial Agricultural Water Balance and Accounting) were employed. The optimal cropping pattern (OCP) was designed to minimize applied irrigation water and was compared with the current cropping pattern (CCP) as well as a proposed cropping pattern from the Agricultural Jahad Organization (CPAJO) for the province for the cropping year 2023-2024. The results indicated that in the OCP, compared to the CCP, the cultivated area for the following crops decreased: wheat by 30%, barley, grain maize, silage maize, alfalfa, sugar beet, potato, cold- season legumes, and cold-season oil crops by 60%, rice by 80%, warm-season fruit trees by 42%, and vegetables by 13%. Conversely, the cultivated area for warm-season legumes and cold-season fruit trees each increased by 60%, while cold-season legumes increased by 150%. To meet the adaptation goals for water scarcity and sustainable agriculture outlined in this study, a 24% reduction in the irrigated cultivation area of the province was deemed necessary. The OCP achieved a 34% reduction in applied irrigation water at the provincial level without decreasing farmers' income. Compared to the CCP, the OCP led to a 32% reduction in the amount of plant production (by weight) at the provincial level. However, prioritizing plants with higher gross economic profit and lower water consumption over those with lower gross economic profit and higher consumption resulted in the gross economic return of the OCP being comparable to that of the CCP and the CPAJO. The comparison of OCP with CPAJO indicated that the CPAJO has not seriously considered adaptability to water scarcity or agricultural sustainability. The CPAJO needs to be reviewed and optimized to address water scarcity and ensure production stability in light of the impacts of excessive water withdrawal in the province.
H.r. Zare Guildehi, H.a. Alikhani, H. Etesami, M. Shirinzadeh, Z. Karami, M. Gholami,
Volume 29, Issue 1 (Spring 2025)
Abstract
Soil and water pollution and waste of resources have occurred due to the excessive use of nitrogen fertilizers in paddy fields. Considering that the biofilm of periphyton formed in paddy fields is mainly responsible for the exchange of nutrients, the present research was designed to investigate the effect of periphyton in the nitrification process in paddy fields and performed with 12 treatments. The treatments included powerful and weak nitrifiers isolated from periphyton, periphyton, periphyton enriched with nitrifiers, and their combination with a dicyandiamide chemical inhibitor. The research was carried out in a rice greenhouse cultivation for 30 days. The results showed that the simultaneous application of periphyton enriched with low-power nitrifier and dicyandiamide can increase the amount of total soil nitrogen, soil phosphorus, soil ammonium, total plant nitrogen, plant phosphorus, plant potassium, shoot length, and dry weight of rice plants. While this treatment reduced the conversion of ammonium to nitrate and subsequently reduced the potential of nitrate formation in the soil, with the increase of ammonium accumulation, it increased the utilization of rice plants. Periphyton can be considered a source for the isolation of nitrifiers. Also, the use of periphyton in paddy fields as a biological and healthy solution to inhibit the nitrification process in front of the use of inhibiting chemicals is placed in the path of future research.
L. Babakhah, A. Khoshfetrat, E. Delavari,
Volume 29, Issue 1 (Spring 2025)
Abstract
Piano key weirs are a new form of labyrinth weirs and exhibit nonlinear characteristics. Due to their high efficiency regarding flow capacity, it is crucial to investigate local scour and identify solutions to mitigate it. Local scour was examined downstream of a trapezoidal piano key weir type B for the first time in this study. The weir was installed 5.50 m from the start of the channel and has a height of 0.20 m, featuring three cycles (three outlet keys, two inlet keys, and two inlet half keys). Three tailwater depths and three different flow rates were also utilized. The maximum scour depth increases with a higher densimetric Froude number and flow rate while decreasing with tailwater depth. The range of the dimensionless parameter for the densimetric Froude number in this study varies between 1 and 2. Additionally, sand and gravel were employed as two types of bed materials. As the diameter of the bed material increases, the maximum scour depth decreases. The scour index for gravel bed material is significantly lower than that for sand material, indicating that the risk of weir overturning is much lower in gravel bed material.
M. Khoshoei,
Volume 29, Issue 2 (Summer 2025)
Abstract
The issue of water scarcity or the limited availability of water resources, including concepts such as water stress, water shortage, and water crisis, is investigated in this study. Water stress refers to problems related to access to freshwater resources, particularly due to the excessive withdrawal of surface and groundwater. A water crisis describes a situation where the available clean and safe drinking water in a specific region is insufficient to meet demand. Factors like drought, reduced rainfall, and pollution can exacerbate water stress. Water shortage arises from reasons such as the inability to meet demand, economic competition over water quality and quantity, conflicts among users, the irreversible depletion of groundwater resources, and negative environmental impacts. This study provides an index to assess water stress for spatial analysis in the study area and analyzes relevant data by collecting information from various sources. This index utilizes both static and dynamic parameters to estimate drought and better depict water stress conditions. Static parameters include land use, slope, and soil type. Dynamic parameters include precipitation, temperature, and groundwater level. Kashan County was selected as the case study due to the continuous reduction in water resources. The results showed that in the water years 2005, 2014, 2020, and 2021, Kashan experienced the highest level of water stress, while in the water years 2002, 2004, 2010, 2012, 2013, and 2015, it experienced the lowest level of water stress.
M. Asadi, M. Noshadi, A.r. Noshadi,
Volume 29, Issue 2 (Summer 2025)
Abstract
In this research, drinking water quality was investigated using acceptability, health, and nutrition-based indicators from 2010 to 2022 in Shiraz City (Fars province). Magnesium, fluoride, and calcium play a significant role in the contribution of drinking water in Shiraz City to the intake of dietary minerals. The acceptability water quality index (AWQI), health-based water quality index (HWQI), and drinking water quality index (DWQI) rankings in Shiraz City are excellent, but the average drinking water nutritional quality index (DWNQI) of Shiraz City is 77.52 ± 5.47, which falls within the good ranking. Therefore, while the conventional water quality indices (AWQI, HWQI, and DWQI) are excellent, the DWNQI index does not achieve an excellent rating, due to the inclusion of the nutritional value of water in the DWNQI index. In general, the trend of AWQI, HWQI, DWQI, and DWNQI over thirteen years in Shiraz City shows that the conventional drinking water quality indices (AWQI, HWQI, and DWQI) do not provide an accurate picture of the assessment of drinking water quality in many cases, as they do not consider the nutritional role of water. For this reason, water is sometimes treated more than necessary. Therefore, it is essential to revise the interpretation of drinking water quality using the DWNQI index to gain a comprehensive picture of drinking water quality.
S.a. Ghaffari Nejad, F. Moshiri, S.m. Mousavi,
Volume 29, Issue 2 (Summer 2025)
Abstract
This study was conducted to evaluate soil fertility management scenarios including separate use of chemical and organic fertilizers (animal manure and municipal waste compost) and their integrated application on changes in the amount of available nitrogen, phosphorus, and potassium in the soil from November 2017 for four years in six consecutive crops at the Agricultural Research Station of the Soil and Water Research Institute. The results showed a depletion of 14 and 44% of soil available nitrogen and phosphorus, and no depletion of available potassium in the treatment without fertilizer in six consecutive cultivations. Annual consumption of 20 t ha-1 of municipal waste compost and 75% of the recommended nitrogen showed the highest amount of soil-available nitrogen. Unlike phosphorus, the amount of soil available nitrogen in municipal waste compost treatments was significantly higher than in cattle manure. The highest available soil phosphorus was in the treatment with 10 t ha-1 of cattle manure before each crop, and the average available phosphorus in six consecutive cultivations was significantly higher than in the other treatments. The use of 10 t ha-1 of cattle manure and municipal waste compost before each crop resulted in the highest accumulation of potassium in the soil, respectively. The available soil potassium in cattle manure treatments was significantly higher than in municipal waste compost. The results of this experiment indicated the importance of using fertilizers containing nitrogen, phosphorus, and potassium in maintaining soil fertility stability in the long term.
M.r. Shoaibi Nobariyan, M.h. Mohammadi,
Volume 29, Issue 2 (Summer 2025)
Abstract
The objective of this study is to investigate the effects of solutes and water quality on evaporation amount and rate in two sandy and clayey soils. Soil samples containing aggregates and sand particles with diameters ranging from 0.5 to 1 millimeter were collected. Six columns were prepared during the experiment; three columns were filled with sandy soil and three with aggregated soil, each measuring 60 cm in height and 15.5 cm in inner diameter. One reference column was filled with distilled water. A saturated calcium sulfate solution was added to two columns, a 0.01 molar calcium chloride solution was added to two other columns, and distilled water was added to the remaining two. The amount of water lost through evaporation was recorded every 8 to 12 hours by weighing the columns. After approximately 130 days, the columns were sectioned, allowing for the establishment of moisture and solute concentration profiles for each soil column. The results indicated that the first and second stages of evaporation were distinguishable in sandy soil, whereas in clayey soil (aggregated soil), only the first stage of evaporation occurred due to the gradual transfer of water and the continuous hydraulic connection from the surface to the water table. The presence and type of solutes affected the evaporation rate and moisture profile, reducing evaporation and increasing water retention in deeper soil layers. Hydraulic connectivity (calcium sulfate > calcium chloride > distilled water) and the resulting capillary rise of and supply of evaporated water from higher layers caused a greater evaporation rate in the calcium sulfate compared to the calcium chloride and distilled water treatments in both soil types. Additionally, the formation of a salt crust on the soil surface due to solutes disrupted the hydraulic connection with the surface, resulting in decreased evaporation rates and cumulative evaporation.
A. Raisi Nafchi, J. Abedi Koupai, M. Gheysari, H.r. Eshghiazeh,
Volume 29, Issue 3 (Fall 2025)
Abstract
Rice is one of the most important crops and the primary food source for more than half of the world's population. The present study was conducted to compare the direct-seeded rice (DSR) of three rice varieties (Jozdan, Firuzan, and Sazandegi) using surface (DI) and subsurface (SDI) drip irrigation systems. The experiment was performed as a split–split plot arranged in a randomized complete block design with three replications in two years (2019 and 2020) in the research farm of Isfahan University of Technology in Najaf-Abad. According to the results of the variance analysis, the most suitable cultivar for DSR in the region (among the tested cultivars) is Sazandegi with a grain yield of 3400 kg/h-1. The results of this experiment showed that the amount of water consumed in DI was 20% less than in SDI. Also, DSR reduced water consumption by 40% compared to transplanted rice (TPR) in the region. However, the grain yield also decreased by about 45%.
M. Goosheh, A. Azadi,
Volume 29, Issue 3 (Fall 2025)
Abstract
Soil organic carbon provides conditions for better plant growth by increasing soil quality by improving physical, chemical, and biological properties of the soil. Therefore, an experiment was conducted in a randomized complete block design (RCBD) with three replications at the Shavour Agricultural Research Station in Khuzestan Province to investigate the effect of different sources of organic matter on some soil properties and wheat yield. The main plots included cow manure, poultry manure, wheat straw, bagasse, and sugarcane filter cake, and the subplots included three fertilizer levels of 2.5, 5, and 10 tons per hectare. Also, one plot was considered as a control (without organic fertilizer) in each replication. The results showed that the best sources of organic fertilizer available in the province that have had a favorable result in increasing wheat yield and improving soil physical properties are filter cake, cow manure, and sugarcane bagasse fertilizers (with a yield of 4772, 4467, and 4452 kg/ha, respectively). Wheat straw also has the least effect on yield (4019 kg/ha) and plays a major role only in improving soil physical and chemical properties. It is worth noting that since no significant difference was observed between the fertilizer consumption amounts in the overall results, the consumption of 2.5 tons per hectare of each fertilizer source is more economical and is recommended. It also seems that the combined application of filter cake with sugarcane bagasse or cow or chicken manure with wheat straw and stubble, in a total amount of 2.5 tons per hectare, has a more favorable result in increasing wheat yield and improving soil physical properties.
J. Karami, M. Habibi Nokhandan, M. Azadi, A. Rashidi Ebrahim Hesari,
Volume 29, Issue 3 (Fall 2025)
Abstract
The present study investigates shoreline changes along the southern Caspian Sea coast in Mazandaran Province over 24 years (2000-2023) using Landsat 8 and Sentinel-2 satellite imagery. The images were obtained from the USGS and Google Earth Engine platforms, and after geometric and radiometric corrections were processed using near-infrared and shortwave Infrared bands to accurately detect the boundary between land and water. Shorelines were visually extracted from the imagery and digitized for each time interval. Spatial variations in the shoreline were analyzed using the Digital Shoreline Analysis System (DSAS) within the ArcGIS environment, applying statistical methods including Net Shoreline Movement (NSM), Shoreline Change Envelope (SCE), End Point Rate (EPR), and Linear Regression Rate (LRR). The results indicate a significant shoreline retreat in many areas of the study region, alongside a continuous decline in the Caspian Sea water level during the last decade. The integration of remote sensing analyses with atmospheric and hydrological data (temperature, precipitation, and river discharge) improved the accuracy of the results and suggests that the southern coastlines—particularly in Mazandaran—may experience more severe retreat by 2050, if current trends continue. These findings underscore the need for intelligent water resource management and the adoption of climate-adaptive policies in the region.
M. Shayannejad, E. Fazel Najafabadi, F. Hatamian Jazi,
Volume 29, Issue 3 (Fall 2025)
Abstract
Regarding the increasing need for water resources and the decline of surface water resources, awareness of these resources is a crucial need in planning, developing, and protecting them. This research was conducted to model the water quality index (the most widely used feature of determining water quality) using machine learning models (Random Forest and Support Vector Machine) in the Zayandehrood River. Regarding the large number of water quality indices, the NSFWQI index was used in this study. First, this index was calculated, and then, input data, including water quality characteristics of 8 stations over 31 years, and the river water quality index were used. In this research, 80% of the data was used in the training stage, and the remaining 20% was used in the evaluation stage. The optimal model was selected based on the evaluation criteria, including R2, CRM, and NRMSE. The results showed that the Support Vector Machine algorithm (0.931 < R² < 0.982, 1.321
A.r. Jafarnejadi, A. Gilani, F. Meskini-Vishkaee, M. Hoseini Chaleshtori,
Volume 29, Issue 3 (Fall 2025)
Abstract
Rice, as one of the world's most strategic crops, plays a vital role in global food security. This study investigated the effects of different nutrition management approaches on yield and water productivity in dry direct-seeded rice cultivation (local Anbouri Red Dwarf cultivar) at Shavoor Research Station in Khuzestan Province. The experiment was conducted in a randomized complete block design with four treatments, including 1) Farmer's conventional practice, 2) Soil test-based fertilization, 3) Soil test-based fertilization + supplementary nutrition, and 4) 25% reduced chemical fertilizers + biofertilizers, with three replications. Results demonstrated that the supplementary nutrition (4270 kgha-1) and biofertilizer with 25% chemical fertilizer reduction (4356 kgha-1) treatments increased yield by 17% and 19.3 %, respectively, compared to conventional practice (3651 kgha-1). This improvement was primarily attributed to increased panicles per m² (10-14%) and enhanced nutrient uptake efficiency. The biofertilizer treatment also showed the highest water productivity (0.25 kg m-³) and the best benefit-cost ratio (23.25). Economic analysis confirmed that combining biofertilizers with 25% chemical fertilizer reduction significantly reduced costs while maintaining yield. These findings suggest that integrating soil testing with either biofertilizers or stage-specific nutrition represents an effective strategy for enhancing yield, improving water use efficiency, and reducing dependence on chemical inputs in dry-seeded rice cultivation. These methods can be recommended as sustainable models for farmers in arid regions like Khuzestan, which face salinity challenges and water resource limitations.
