Maryam Salehi Lande; Maasoumeh Movaghari; Nafiseh Rang Zan; Leila Khalasi Ahvazi
Volume 33, Issue 1 , May 2026, , Pages 41-50
Abstract
AbstractBackground and objectivesMonitoring and evaluating the effectiveness of implementing any type of project, including land reclamation projects, helps relevant managers in making better decisions for future projects. The present research aims to investigate the chemical, physical and hydrological ...
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AbstractBackground and objectivesMonitoring and evaluating the effectiveness of implementing any type of project, including land reclamation projects, helps relevant managers in making better decisions for future projects. The present research aims to investigate the chemical, physical and hydrological characteristics of planting with species Seidlitzia rosmarinus Boiss ex B., Tamarix passerinoides Delile ex Desv. and Prosopis juliflora SW. DC. in south and southeast of Ahvaz.MethodologySoil samples were collected in four areas (control (no planting), S. rosmarinus, T. passerinoides, and P.juliflora), at two distances (under the crown and outside the crown) and at two depths (0-30 and 30-60 cm). The collected soil samples were transferred to the laboratory and after preparing a composite soil sample; its properties were measured in three replicates. some physical properties (bulk density by clod method, soil aggregate stability by sieve method, penetration resistance by penetrometer), some chemical properties (soil pH using the saturated extract method and a pH meter, electrical conductivity using the saturated extract and EC meter, total soil nitrogen by Kjeldahl method, available phosphorus using the Olsen method with Spectrophotometr, soluble potassium in soil saturation extract by flame photometer, and organic matter by the ignition method), and some hydrological properties (soil moisture by weight percentage) were measured. In addition, the soil infiltration rate was compared by establishing two double cylinders in the control area and the planted area.Results The results of this study showed that nitrogen percentage and penetration resistance had significant differences between the control area and planting areas. Planting with each species reduced the soil penetration resistance, and the highest value of this index was related to the control area and the lowest value was related to the T. passerinoides and then P.juliflora. In addition, T. passerinoides and P.juliflora increased soil nitrogen content and reduced soil pH compared to the control area. Also, the results of comparing the average soil properties under the canopy and outside the canopy of the plants and in two studied depths showed that under the canopy of the T. passerinoides, the electrical conductivity of the first depth of the soil decreased and its organic carbon increased. Similar also S. rosmarinus, caused a decrease in the electrical conductivity of the soil and an increase in organic carbon under the canopy, with the difference that the increase in organic carbon also occurred outside the canopy. While P.juliflora increased the electrical conductivity and pH of the soil under the plant crown compared to outside the crown. Also, the results obtained from the Kostiakov infiltration equation comparing the infiltration rate between the control area and the planted area showed that planting in this area increased the infiltration rate by 124% compared to the control area.ConclucionIn general, the results of this study on the non-native species of P.juliflora showed that despite the effect that this species had on reducing soil penetration resistance and increasing soil nitrogen content compared to the control area, but it also increased electrical conductivity and pH under the plant crown While the two native species, T. passerinoides and S. rosmarinus, led to a decrease in electrical conductivity and increase in soil organic carbon under the plant crown and even outside the plant crown (in the case of S. rosmarinus). Therefore, despite the positive effects of native species on soil properties in this study, planting of these plants is prioritized over the non-native species, P.juliflora.
Seyedeh Fatemeh Arab; Javad Bazrafshan
Volume 32, Issue 3 , September 2025, , Pages 255-276
Abstract
AbstractBackground and ObjectivesDrought is typically characterized as a temporary deficit in water resources relative to normal regional conditions. This slow-onset phenomenon occurs across all climate zones but exhibits complex structures and region-specific impacts. Extreme droughts are distinguished ...
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AbstractBackground and ObjectivesDrought is typically characterized as a temporary deficit in water resources relative to normal regional conditions. This slow-onset phenomenon occurs across all climate zones but exhibits complex structures and region-specific impacts. Extreme droughts are distinguished by their intensity in severe or very severe classes. In drought research employing conventional indices, the identification of extreme droughts depends on analysis across different time scales. The concept of super-drought extends this framework by considering drought occurrences across multiple timescales, providing a broader perspective beyond extreme droughts. Identifying superdroughts involves statistical integration of drought signals at various time scales. International studies on superd-roughts—initiated nearly a decade ago—have significantly advanced our understanding of drought dynamics. This phenomenon is crucial as it reflects the prolonged impact of droughts on regional water and ecological systems. Consequently, this study seeks to explore the potential occurrence of super-droughts, analyze their characteristics, and assess their effects on vegetation, with Khuzestan Province serving as the study region.Materials and MethodsThis research utilizes daily meteorological data—including precipitation, temperature, relative humidity, wind speed, and sunshine hours—from five synoptic stations in Khuzestan Province: Ahvaz, Bandar Mahshahr, Masjed Soleyman, Safiabad Dezful, and Bostan, covering the period 1990–2019. Additionally, NDVI data obtained from the MODIS satellite (Terra sensor, product MOD13A3, spatial resolution of 1 km²) spanning 2000–2019 was analyzed. For each station, an 81-pixel region (9×9 grid) was selected, and the median NDVI value was calculated monthly to serve as the vegetation index. Following quality control and gap filling, the Standardized Precipitation-Evapotranspiration Index (SPEI) was computed across five time scales: 3, 6, 12, 24, and 48 months. Subsequently, the Composite Drought Index (CDI) was derived by applying the Vine copulas technique to these SPEI scales, a method capable of capturing the complex dependence structure among the indices. The relationship between CDI and NDVI was then statistically modeled at each station.ResultsFindings indicated that the Vine copulas method effectively analyzed the dependence across the five SPEI time scales. The resulting CDI enabled the identification of superdrought events within the study area. While some stations experienced similar drought periods, no singular dry spell was common across all five stations. For example, the most intense drought episodes were observed at Masjed Soleyman in December 2001, and at Ahvaz, Bandar Mahshahr, and Safiabad Dezful in various other years.The correlation between CDI and NDVI was predominantly positive and statistically significant throughout most months, with the highest correlations at Safiabad Dezful between February and April (r > 0.7). At Bostan, this positive relationship persisted nearly year-round. Notably, during the hotter months at Safiabad Dezful, a significant negative correlation emerged, indicating that heightened thermal stress can weaken vegetation even amidst drought conditions.ConclusionThe study demonstrates that the Vine ccopulas method, by integrating multi-scale SPEI data and accounting for their complex interdependencies, effectively identified superdrought events over a 30-year period at the selected stations. In contrast, a straightforward comparison of SPEI values across scales, without the Vine approach, revealed only a limited number of superdroughts, with Bostan’s station showing none. The CDI showed a strong correlation with NDVI, confirming its utility in detecting drought-related vegetation stress. Generally, increased drought intensity corresponded with decreased vegetation greenness, attributable to water deficits, although during certain hot months, vegetation greenness increased due to thermal stress effects. Future research should consider the sensitivity of CDI to the specific thresholds of drought occurrence, as well as its dependence on the underlying SPEI scales, to refine drought monitoring and ecological impact assessments.
Somayeh Dehdari; Masoomeh Movaghari Rodposhti; Zohreh Khorsandi Koohanestani; Ali Ehsani
Volume 25, Issue 1 , April 2018, , Pages 227-234
Abstract
The reduced biomass in forests and rangelands ecosystems for any reason can affect the process of carbon sequestration and as a result of global warming. This study was conducted to assess carbon storage under different grazing intensities in rangeland of Chah Mary dominated with Artemisia ...
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The reduced biomass in forests and rangelands ecosystems for any reason can affect the process of carbon sequestration and as a result of global warming. This study was conducted to assess carbon storage under different grazing intensities in rangeland of Chah Mary dominated with Artemisia siberi in Khuzestan province. Three sites under heavy, moderate and low grazing intensities were selected based on similar topographic features (slope, aspect and elevation), rainfall, soil and climate. Plant sampling was done in key areas by random-systematic method along three transects of 100m and 60 plots of 1m2. Then, aerial and underground biomass parameters were evaluated in each plot and carbon was determined by ash method. The data were analyzed by SPSS v.16 software. According to the results, carbon sequestration decreased from 5704/3 in the low-grazing region to 3470/1 in the high-grazing region. Also, under low-grazing intensity, the carbon stored in aerial biomass and underground biomass was 4360/9 and 2180/5, respectively.
Zeynab Gandomi; Amir Hosein charkhabi; Hasan Mohseni; Manouchehr Amiri
Volume 24, Issue 4 , January 2018, , Pages 897-906
Abstract
The southwest province of Iran has a dry and semi-arid climate, with about 250,000 hectares of sand dunes; therefore a comprehensive review and overview of these features and their correlation with other features is needed. In this study, over 200 sand samples were collected from the ...
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The southwest province of Iran has a dry and semi-arid climate, with about 250,000 hectares of sand dunes; therefore a comprehensive review and overview of these features and their correlation with other features is needed. In this study, over 200 sand samples were collected from the mobile and not mobile sand dunes to study the grain size of sand dunes in Khuzestan. The results showed there was no significant difference in the mean grain size from east to west, along a 200 km transect of the sampled area. The mean grain size in the west was 2.87 to 2.14 φ scale (136 to 226 microns) and in the east 3.05 to 2.16 φ (120 to 223 microns). The standard deviation of particle size of the samples was good and fairly good (0.71 to 0.35 φ). Using tilt condensation particle diameter in the range of sand dunes area, folk scale (0.1 to 1 φ) was positive. These distances represent 20 to 50 km with mean transported distance of 35 km for the west and 50 to 200 km transported distance with mean value of 125 km for the east section of the Khuzestan province for the sand dunes. For the transport distances, average transport distance could be divided into four categories, including 3, 12.5, 35 and 125 km. According to the results, the source of particles of the sand dunes in Khuzestan province is local, mainly from northwest and west.
Kurosh Behnamfar; Ebrahim Rahmani; Hossein Heidari Sharifabad; Mohammad hassan Salehe Shoshtari
Volume 17, Issue 4 , November 2011, , Pages 527-537
Abstract
Nitrogen is one of the most important macro nutrients in plants which its shortage in soil is the main factor limiting plant growth. Nitrogen molecular gas comprises about 80 % of the atmospheric gases whereas it is not directly absorbable in plants. A symbiosis of legumes and rhizobia is one of ...
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Nitrogen is one of the most important macro nutrients in plants which its shortage in soil is the main factor limiting plant growth. Nitrogen molecular gas comprises about 80 % of the atmospheric gases whereas it is not directly absorbable in plants. A symbiosis of legumes and rhizobia is one of the most important ways in nitrogen fixation. Fertilizer application in rangelands especially in arid and semi arid regions which always faces limiting moisture will result in small efficiency of the fertilizer and also imposes heavy costs due to environmental pollution (soil and water). Native Trifolium species are of utmost nitrogen fixers in Khuzestan rangelands. This experiment was carried out in 3 years to isolate, identify and introduce rhizobium strain of the native Trifolium species in Khuzestan. A total number of 70 samples were collected from 12 Trifolium species and after root washing and separation of root nodules in laboratory, the rhizobium bacteria were planted and isolated on YMA. Finally, 9 strains of Rhizobium trifolli were identified based on morphological characteristics and growth rate.
Hamid Hoveizeh; Amrali shahmoradi
Volume 16, Issue 2 , December 2009, , Pages 200-208
Abstract
Accessibility to a major portion of basic information about vegetation function of rangeland ecosystems is provided via autecologcal study of range plant species. These information are required for proper management of related rangelands. This research was conducted to examine the autecology of Cenchrus ...
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Accessibility to a major portion of basic information about vegetation function of rangeland ecosystems is provided via autecologcal study of range plant species. These information are required for proper management of related rangelands. This research was conducted to examine the autecology of Cenchrus ciliaris in Khuzestan Province of Iran. Some topographic, climatic, and edaphic characteristics, as well as the boundaries of its natural habitats were determined. Also, the phenological stages of the plant were observed. Results showed that the habitats of this plant species are mainly located in south western and south eastern sections of the province, with east and south topographic aspects and altitudes ranging from 60 to 420 meters above sea level. This range plant generally grow on sandy loamy soils of the province. The soils of these habitats are slightly to moderately accompanied with debris and sandstones. Average annual precipitation at its habitats is 233-341 millimeters. Fall vegetative growth of this species began earlier than accompanied native species.
Hamid Hoveyzeh
Volume 9, Issue 2 , September 2001, , Pages 505-512