Yaser GHasemi Arian; Hadi Eskandari Dam aneh; Maryam Naeimi; Adel Jalili; Samira Zandifar; Azadeh Gohardoust; Sakineh Lotfinasabasl
Volume 32, Issue 1 , May 2025, , Pages 1-17
Abstract
Background and objectivesLand subsidence, primarily caused by excessive groundwater extraction, constitutes the most advanced and irreversible stage of desertification and land degradation. While this phenomenon poses a significant threat to numerous plains and major urban centers across Iran, existing ...
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Background and objectivesLand subsidence, primarily caused by excessive groundwater extraction, constitutes the most advanced and irreversible stage of desertification and land degradation. While this phenomenon poses a significant threat to numerous plains and major urban centers across Iran, existing desertification assessment models have largely overlooked subsidence rates and the agricultural sector's substantial groundwater consumption. This study evaluates desertification intensity in the Qaraqom basin through the dual lenses of water resource utilization and land subsidence dynamics.MethodologyThe study employed the Inverse Distance Weighting (IDW) method in GIS 10.8 to create zonation maps for three critical groundwater indices: electrical conductivity (EC), sodium adsorption ratio (SAR), and groundwater level decline. Data from 273 observation wells (2001-2018) were classified into four desertification intensity categories (low, moderate, severe, and very severe). These maps were integrated with a land subsidence rate map (2015-2016 water year) derived from Sentinel-1 satellite imagery provided by the Geological Survey of Iran. Additionally, reservoir volume changes (1985-2018) were analyzed for each aquifer to assess their relationship with subsidence patterns.ResultsAnalysis revealed severe to very severe desertification across 46.6% of the basin based on EC values, while SAR indicated low degradation in 90.6% of the area. Groundwater depletion showed the most critical conditions, with 53.4% of the basin experiencing severe to very severe impacts, particularly in the Sarakhs, Fariman-Torbat Jam, southwest Mashhad, and Narimani aquifers. Subsidence rates reached severe levels in 18.1% of the basin, with maximum values observed in the Mashhad, Fariman-Torbat Jam, Taybad, and Karat aquifers. The Mashhad aquifer demonstrated the highest subsidence rates and the most significant reservoir volume changes. Integrated assessment of groundwater and subsidence criteria classified 55.9% of the Qara Qom watershed as moderately affected and 26.1% as low-intensity desertification.ConclusionAs agriculture represents the dominant water consumer in the basin, immediate implementation of water efficiency and productivity measures in this sector is crucial to prevent irreversible socio-economic and ecological consequences of ongoing desertification and land degradation.
Mohsen Shabani; Maryam Azarakhshi; Jalil Farzadmehr; Masoud Bazrafshan
Volume 26, Issue 2 , July 2019, , Pages 423-431
Abstract
The cultivation of plants that are resistant in difficult environmental conditions is an effective solution for reclamation of lands; thus, recognizing the effects of cultivation of different plants on soil and vegetation cover could be a suitable guide to select proper species by ...
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The cultivation of plants that are resistant in difficult environmental conditions is an effective solution for reclamation of lands; thus, recognizing the effects of cultivation of different plants on soil and vegetation cover could be a suitable guide to select proper species by experts. The aim of this research was to investigate the effects of range improvement and reclamation practices on soil and vegetation cover characteristics in Jannat Abad rangeland. For this purpose, four transects of 100-m length and two transects of 100-m length were established with 100-m intervals in the seedling area (Atriplex canescens and Haloxylon aphyllum) and the control area (natural vegetation), respectively. Along each transect, 10 plots of 4m2 were sampled. In each plot, the vegetation data including canopy cover percentage, litter, gravel, bare soil, dominant species, and plant density were measured. Soil profiles were dug at the beginning and end of each transect. Soil sampling was performed from 0-30, 30-60 and 60-90 cm depths. Then, soil chemical and physical properties including electrical conductivity, pH, organic matter, phosphorus, potassium, nitrogen, bulk density, clay, silt, and sand percentage. The collected data were analyzed by independent t-test with SPSS software. Results showed that the cultivation of Atriplex canescens caused an increase in canopy cover percentage, density, and potassium content in the first and second depths (P<0.01), and caused an increase in the nitrogen content of the first depth, organic matter of the second depth, electrical conductivity of the first and second depths, and silt percentage in the first and third depths (P<0.05). It also caused a decrease in soil pH and sand percentage of the second and third depths (P<0.05). The cultivation of Haloxylon aphyllum caused an increase in density, electrical conductivity of the first depth, and a decrease in clay percentage in the third depth (P<0.05), compared to the control area.
Leila Biabani; Gholamreza Zehtabian; Hasan Khosravi; Mahin Hanifepour
Volume 26, Issue 1 , June 2019, , Pages 158-17
Abstract
Managing the optimal use of water resources is one of the most important issues in sustainable development. Considering the importance of studying groundwater in the field of drinking, industry and agriculture, the study of water qualitative changes can be important for humankind. ...
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Managing the optimal use of water resources is one of the most important issues in sustainable development. Considering the importance of studying groundwater in the field of drinking, industry and agriculture, the study of water qualitative changes can be important for humankind. In this study, groundwater level depletion and electrical conductivity (EC) were used to investigate the quantitative and qualitative changes of groundwater in Karaj plain. The water level hydrographs were drown using Thiessen method based on the piezometric wells data and the groundwater depletion, the elevation contour line, and iso- electrical conductivity maps were provided using GIS. Quantitative changes were studied with reading of each well in different months in a 15-year period (2001-2016). The obtained results showed that the vast range of Karaj plain was depleted due to the lack of proper recharge as well as the over-exploration of groundwater. In addition, the relation between EC and anions and cations (such as Ca2+, Mg2+, K+, Cl-, Na+, SO42-, HCO3-) were determined. The calculated Standard Index of Annual Precipitation (SIAP) in five meteorological stations showed groundwater depletion due to rainfall reducing and drought. Electrical conductivity had direct relation with concentration of ions in all cases. According to the hydrographs, the average level of groundwater decreased to 1.02 m over 15 years and the groundwater level depletion consequently decreased the water quality.
Mina Arast; Gholamreza zehtabian; Mohammad Jafari; hasan khosravi; saeed shojaee
Volume 23, Issue 3 , January 2017, , Pages 543-554
Abstract
The used of unconventional waters in the agricultural lands not only reduces the environmental hazards but also increases the productivity. This research was aimed to assess the effects of wastewater, saline water and brackish water on some soil properties including organic matter, bulk density, and ...
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The used of unconventional waters in the agricultural lands not only reduces the environmental hazards but also increases the productivity. This research was aimed to assess the effects of wastewater, saline water and brackish water on some soil properties including organic matter, bulk density, and electrical conductivity. Therefore, five study sites were selected. The treatments consisted of control, irrigation with saline water, brackish water, and wastewater as well as mixed irrigation of wastewater and saline water. Five profiles were dug in the study sites. In each profile, two samples were taken from two depths of 0-30 cm and 30-60 cm. The results showed that irrigating with wastewater led to improved soil properties in terms of organic matter and bulk density, as compared with other treatments. There was no significant difference in pH among all treatments. However, the amount of Electrical Conductivity of saline water in surface and deep layers of soil was 17.57 ds/m and 5.5 ds/m, respectively. This large difference between the two depths in saline water treatment represents the EC downward trend from surface to depth. This trend was constant for the brackish water and wastewater treatments.