Morteza Abtahi
Volume 28, Issue 4 , November 2021, , Pages 605-613
Abstract
Biological stabilization of dunes is one way to prevent wind erosion and the creation of sandstorms. Clligonum is one of the plant species that due to its unique root structure can settle in the dunes and stabilize them. In this study, we intend to investigate the most suitable species and age of Calligonum ...
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Biological stabilization of dunes is one way to prevent wind erosion and the creation of sandstorms. Clligonum is one of the plant species that due to its unique root structure can settle in the dunes and stabilize them. In this study, we intend to investigate the most suitable species and age of Calligonum shrub for planting in three different points of Kashan long sand. This research is in the form of split-plot (split plots) based on the randomized block design. Analysis of variance showed that the differences between different locations and the age of different seedlings and species of Calligonum were significant at the level of (p≤0.01). In all three age groups, Calligonum turkestanicum with 61.15% had the highest establishment, and C. comosum is in the second rank, and C. schizopterum and C. bungei species were in the third and fourth ranks, respectively. Siazgeh region, with an average of 59.7%, has the highest percentage of seedlings. Three-year seedlings, with an average of 58.7%, had no significant difference with two-year seedlings with an average of 57.01% and with one-year seedlings with an average of 53.84% at the level of (p≤0.01).Accordingly, the use of 0biennial C. turkestanicum seedlings and three-year C. comosum seedlings is recommended for sand stabilization in Kashan region.
Mojtaba Pakparvar; Morteza Abtahi
Volume 8, Issue 4 , September 2019, , Pages 93-122
Mehdi Jafari; Gholam Reza Zehtabian; Amir Houshang Ehsani
Volume 20, Issue 1 , June 2013, , Pages 72-87
Abstract
Today, remote sensing data can provide the latest information for the study of land cover and land uses These images are of utmost importance due to the providing updated information, variety of forms and the possibility of processing for making land use maps. Determining the location of each land use ...
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Today, remote sensing data can provide the latest information for the study of land cover and land uses These images are of utmost importance due to the providing updated information, variety of forms and the possibility of processing for making land use maps. Determining the location of each land use together with land cover helps managers in making decisions. Also, the current status of the land cover can be studied by using land use maps at different levels. In order to evaluate the ability of multitemporal satellite data of TM and ETM + in land use classification and the effect of the thermal band on increasing the accuracy of the land use maps, Landsat TM digital data relating to the September 27, 1990 and Landsat ETM + digital data of 10 July 2002 from Kashan were analyzed. Initial studies were performed on images in terms of the presence of geometric errors. In order to prepare the images for digital processing, improved operation and image enhancement were applied on the images. Ground truth map was prepared in the same stage. Then, the supervised classification of satellite images with algorithms and different approaches including a variety of bands were tested and the accuracy of each of the methods and approaches were investigated. The results showed that the highest Kappa accuracy in both Landsat TM and ETM + with all the bands were 86.34 and 83.21, respectively. While the elimination of the thermal band decreases the accuracy to 82.46 and 79.93 % The results of this study showed that using thermal bonding caused an increase of 4 percent in Kappa accuracy, and the highest accuracy was occurred in the classes of clay plains, flood plains, mountains and puffy salt lands. Therefore, despite the lower spectral resolution, the use of thermal bonding is recommended in such studies.
Hosein Azarnivand; Ali Tavili; Ali Sadeghi Sangdehi; Mohammad Jafari; Mohamad ali Zare Chahouki
Volume 18, Issue 3 , September 2011, , Pages 372-383
Abstract
Understanding ecological needs of range species is of utmost importance for range managers in conservation and utilization of rangeland ecosystems. The current research was conducted to find out ecological characteristics of Astragalus squarrosus in Kashan. In each study area, soil sampling was performed ...
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Understanding ecological needs of range species is of utmost importance for range managers in conservation and utilization of rangeland ecosystems. The current research was conducted to find out ecological characteristics of Astragalus squarrosus in Kashan. In each study area, soil sampling was performed at depths of 0-30 and 30-60 cm along four transects. Vegetation sampling was done in three phonological stages of vegetative growth, flowering and seed ripening. Soil studies of the mentioned species showed that it mainly grew in soils with sandy loam to loamy sand textures, EC of 0/4 -4/2 ds/m and pH of 7/49 -8/17. According to the results of the vegetation studies, average of the current yield was 78/3 kg/ha and 1322/9 species per hectare was estimated as average of the density of A. squarrosus. Forage quality analysis at three phonological stages of vegetative growth, flowering and seed ripening showed that the amount of CP and OC were reduced up to 3.6% and 0/82 respectively. Decrease of DMD and ME and increase of ADF values at seed ripening stage was associated with a considerable decrease in palatability and subsequently forage quality.