Showing 411 results for Om
V. Rahdari, A.r. Soffianian, S. Pormanafi, S. Maleki,
Volume 27, Issue 3 (12-2023)
Abstract
Industrial development is necessary to create employment and achieve welfare. Nevertheless, due to the important environmental effects of these uses, it is necessary to consider the environmental issues in industrial area land allocation. The current research used the multi-criteria evaluation method and the combination with fuzzy concepts to investigate the land capability for industrial development in the Plasjan sub-basin in the Zayandeh-rood river basin. Evaluation criteria were determined by literature reviewing and using experts' knowledge, and standard applying fuzzy method via proportional functions and weighted using the hierarchical method. The combined classification of satellite images prepared the land use and land cover map. Then, the standardized criteria were combined in the form of a weighted linear combination and the industrial development capability model was prepared for this area and classified into five land capability classes. The results showed that environmental considerations have the most weight with 0.23, and geological and soil texture criteria have the least weight with 0.06. According to the results, only 213 hectares of the region were allocated for industrial and mining use at the time of the study. In comparison, 2325 hectares of the region have very high industrial potential which shows the capability for increasing industrial areas. Also, the highest class of land capability was related to areas without the capability for industrial development with an area of 246375 ha, equivalent to 60% of the entire region, which shows the importance of conservation of the important functions of this region in water supply and ecological resources.
S. Barani, M. Zeinivand, M. Ghomeshi,
Volume 27, Issue 4 (12-2023)
Abstract
In this study the effect of orifice number and dimensions in combined structure sharp crested rectangular weir with multiple square orifice was investigated. For this propose, some experiments in different flow rate, different orifice number and dimensions were done. The results showed that by different orifice numbers and dimensions, flow discharge increased at the same upstream flow head. This increasing trend was observed in all numbers and dimensions of the investigated experiments. The analysis of the quantitative results showed that by increasing the number of orifices, the discharge rate through the combined structure of weir-orifice was increased on average 2.06 liters per second and by increasing each centimeter of orifice dimensions, the discharge was increased by 2.82 liters per second. Also by calculating the percentage of flow rate increase, it was observed that by adding the orifice number, it increases by 18.7% and by increasing the size of the orifice by one centimeter, the flow rate increases by 28.1%.
Z. Naderizadeh, H. Khademi, A. Shamsollah,
Volume 28, Issue 1 (5-2024)
Abstract
Although several reports are available on the distribution of Palygorskite in the soils of arid regions of Iran, there is not much information about the presence and abundance of this important fibrous clay mineral in the soils of Bushehr Province. This research was carried out: (1) to investigate the distribution of Palygorskite and other major associated clay minerals, and (2) to evaluate the relationship between the relative quantity of Palygorskite in clay-sized fraction and the most important soil properties in Dashtestan County, Bushehr Province. Five geomorphic surfaces including eroded rock outcrop, rock outcrop, dissected hill, alluvial fan, and alluvial plain were identified in the study area using Google Earth images and field observations. After sampling representative pedons, the clay mineralogy of two horizons from each pedon was determined. X-ray diffractograms and SEM images showed that in the studied soils, which were classified as either Aridisols or Entisols, Palygorskite was present in different quantities on all geomorphic surfaces. Moreover, Illite, Chlorite, Smectite, irregularly interstratified Chlorite/Illite, and Kaolinite were the other clay minerals that existed in the soils studied. The relative quantity of Palygorskite and Smectite was variable on different geomorphic surfaces. Regardless of the type of geomorphic surface, petrogypsic and gypsic horizons showed the highest quantity of Palygorskite as compared to other horizons which seems to be due to the suitable geochemical conditions of these horizons for the formation and stability of Palygorskite mineral. The higher correlation of Palygorskite content with gypsum, as compared to that with the carbonates, indicates the importance of gypsum in Palygorskite distribution in the soils of the study area. The findings also indicated that the amount of Palygorskite was positively correlated with soluble Mg/Ca ratio, pH, gypsum, and soluble Mg. These parameters appear to control the genesis and distribution of Palygorskite in the soils studied. In general, it is necessary to pay special attention to their clay mineralogy, especially the significant amount of Palygorskite to manage the soils of the study area and to reasonably predict their behavior.
M. Khajeh, C. B. Komaki, M. Rezaei, V. Sheikh, L. Ebadi,
Volume 28, Issue 2 (8-2024)
Abstract
In the future, the risk of land subsidence due to water resources shortage crisis and improper water resources management will become more and more dangerous. It is necessary to assess and identify areas susceptible to subsidence risk and take necessary actions to reduce risks related to land subsidence. In this study, first, the risk of land subsidence was identified and evaluated using a radar interferometry method called LiCSBAS. Then, the spatial relationship between the occurrence of land subsidence hazard and effective factors such as ground elevation, slope, slope aspect, lithology, land use, groundwater decline, distance from rivers, distance from faults, topographic moisture index, and arc curvature was investigated using the random forest (RF) model. In the end, the land subsidence hazard sensitivity map was prepared after calibrating the random forest algorithm. The analysis of LiCSBAS interferometric time series data from 2015 to 2022 showed that the center of the Marvdasht-Kharameh plain and adjacent agricultural areas are continuously subsiding and the mean deformation rate map showed a subsidence rate of 11.6 centimeters per year. The results of determining the spatial relationship between subsidence occurrence and effective factors confirmed the positive impact of distance from rivers, urban and agricultural land uses, depth of bedrock (aquifer thickness), groundwater decline, and alluvial and fine-grained formations on this phenomenon. Also, the results of subsidence modeling using the random forest algorithm showed that factors such as bedrock depth, groundwater decline, land use, and geology have the greatest impact on the potential for subsidence occurrence in the study area. Also, based on the results, about 3 to 4 percent of the areas are in the very high and extremely high-risk classes of land subsidence, especially in the center and suburbs of Mervdasht. Therefore, water resources management and control and developing a systematic program to reduce subsidence risk and aquifer recharge conservation in Merudasht-Kharameh Plain is essential.
M.j. Aghasi, S.a.r. Mousavi, M. Tarkesh, S. Soltani,
Volume 28, Issue 3 (10-2024)
Abstract
Astragalus is the vegetation of many mountains of Iran's plateau and plays a major role in providing ecosystem services due to its pillow shape and deep rooting system, they facilitate the control and penetration of precipitation into the soil. The correlation of Astragalus ecosystems with arid and semi-arid climates has made them vulnerable to climate change. In this study, a runoff yield map based on the Budyco curve under current and future conditions of climate change (2050) was prepared using climate and temperature data from the Chelsea site (CanESM2 GCM) in TerrSet software and by using maps of sub-watersheds, annual precipitation, annual potential evapotranspiration, soil depth, plant accessible water and the current and future "Land Cover - Land Use" map, with a combination of field methods and species distribution models at the local scale of the Shur River watershed of Dehaghan (Central Zagros). Finally, the excess runoff damage produced due to climate change was estimated using the replacement cost method. The results indicated an increase in the annual runoff volume of the watershed from 70 million cubic meters to 105 million cubic meters under climate change conditions for the RCP26 scenario in 2050. Taking into account the cost of 10 million Rials for controlling 530 cubic meters of runoff through various watershed management projects, preventing the damages of excess runoff produced requires a credit amounting to 660 billion Rials based on the present value. This study proved the ability of TerrSet software to predict and produce an ecosystem service map of runoff yield under climate changes or land use changes and with the purpose of valuation on a local scale. Also, the above valuation can be the basis for planning and providing credit for the study and implementation of watershed management projects to deal with the threats of climate change.
J. Karimi Shiasi, F. Fotouhi Firoozabad, A. Fathzadeh, M. Hayatzadeh, M. Shirmardi,
Volume 29, Issue 1 (4-2025)
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.
H. Ramezani Etedali, M. Ahmadi,
Volume 29, Issue 2 (7-2025)
Abstract
change, accurately predicting wheat production is essential for developing precision agriculture. Remote sensing enables the indirect prediction of crop production before harvest. This research investigates the application of the random forest method and support vector regression for simulating wheat production across ten selected farms in Qazvin Plain from 2019 to 2020, employing NDVI, MSAVI, and EVI vegetation indices. Sentinel 2 satellite data was utilized for the vegetation indices. Production data for the ten wheat fields was obtained from the Agricultural Jihad Organization of Qazvin Province. Evaluation of support vector regression and random forest to assess both the observed and simulated wheat production data was conducted using R2, MBE, RMSE, and MAE statistics. To explore the simulation of wheat production using vegetation indices, seven methods were defined: methods 1 to 3 examine each index separately; methods 4 to 6 focus on binary combinations of the indices; and method 7 considers the combined effects of all three indices. The support vector regression model provided good estimates of wheat production in all methods, except methods one and four, in the test phase, with a coefficient of determination of more than 0.98 and a low RMSE. The random forest model showed significant results in all methods except methods two and six during the test phase, achieving a 95% probability (P-value=0.00) with a coefficient of determination greater than 0.8. Overall, this research highlights the importance and potential of machine learning techniques for timely crop production prediction as a strong foundation for regional food security.
J. Ghaneiardakani, S.a. Mazhari, F. Ayati,
Volume 29, Issue 2 (7-2025)
Abstract
This study investigates the impact of agricultural activities on the soils of southern Mehriz by analyzing their geochemical composition and comparing the physicochemical properties of pistachio orchard soils (agricultural soils) with those of undisturbed natural soils. The results indicate that agricultural practices have led to an increase in Total Organic Carbon (TOC), averaging 1.5%, and a reduction in soil acidity. Additionally, phosphorus concentrations have risen in agricultural soils. These soils also exhibit enrichment in elements such as cadmium (Cd), antimony (Sb), chromium (Cr), nickel (Ni), lead (Pb), scandium (Sc), and rare earth elements (REE) compared to natural soils, with a more homogenized REE distribution pattern. Although the concentrations of these trace elements remain within national environmental standards and below critical thresholds, the study highlights a significant increase in the bioavailability of heavy metals due to agricultural activity. This finding underscores a potential environmental risk if such changes are not properly managed in the future.
S.a. Ghaffari Nejad, F. Moshiri, S.m. Mousavi,
Volume 29, Issue 2 (7-2025)
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. Shayannejad, E. Fazel Najafabadi, F. Hatamian Jazi,
Volume 29, Issue 3 (10-2025)
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 (10-2025)
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.
