hamidreza abbasi; Mahmood rajabi aleni; sadat feiznia; Mohammad Darvish; mamak ahmadian; ali shahbazi
Volume 22, Issue 3 , November 2015, , Pages 583-594
Kazem Dashtakian; Hamidreza Dashtakian; Mohammad Abolghasemi
Volume 22, Issue 2 , August 2015, , Pages 344-355
Abstract
The source of sandy dunes has been the main question in desert regions. Several theories have been already presented about this question around the world. In addition, several methods have been already invented and applied to find the source of sandy dunes. In this research, the relationship between ...
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The source of sandy dunes has been the main question in desert regions. Several theories have been already presented about this question around the world. In addition, several methods have been already invented and applied to find the source of sandy dunes. In this research, the relationship between playa and sandy area in Yazd province was studied using GIS. At first, the maps of sand dunes and playa in the province as well as neighboring areas were produced. Then, the distance and direction of all sandy polygons to the nearest playa was calculated. Meanwhile, the geographic center of sandy polygons and playa polygons were identified. According to the results, around 60% of sandy polygons had a distance less than 10 kilometers to the playa, and their average distance to the nearest playa was calculated to be 12745 meter. In more than 79% of sandy dunes, the nearest playa was located in the North West. The average angle of playas to the sandy dunes was 332 degree (N), matching with the main windroses and sandroses of province. Therefore, if all sandy dunes and playas are converted to one place, we will have one sandy dune with an average area of 4717 hectares as well as a playa with an average area of 220506 hectares in the northwest of sand dune. Eventually, according to the prevailing wind direction, the hypothesis of the role of playas as the main source of sand dunes in the Yazd province is reinforced.
Zainab Nurikiya; Akbar Javadi; Akbar Fakhireh; Ali Tavili; Mohammad ali Zare chahouki; Hamid reza Abbasi
Volume 16, Issue 4 , January 2010, , Pages 574-585
Abstract
The purpose of this research was to compare the amount of N, P and K in the soil under three rangeland species i.e. Agropyron tauri, Astragalus ammodendron and Bromus tomentellus and (with) the soil properties of the control area. After identifying the habitats (sites) of the mentioned species, soil ...
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The purpose of this research was to compare the amount of N, P and K in the soil under three rangeland species i.e. Agropyron tauri, Astragalus ammodendron and Bromus tomentellus and (with) the soil properties of the control area. After identifying the habitats (sites) of the mentioned species, soil sampling was done in all key areas at the end of the growing season based upon randomized systematic method. In order to study the features of the mentioned species, 10 plots (1 m2) were established along 4 transects.Soil sampling was carried out in the beginning and in the end of all transects from 0-10 and 10-40 cm soil depths. Soil sampling was also done in the control area and then N, P and K were measured. All data were analyzed and compared by T test. The results indicate that the amount of N, P and K in the first soil depth beneath Agropyron tauri is more than that in Astragalus ammodendron and Bromus tomentellus. In most cases the amount of N and K in the soil beneath (under) the species are more than that in the control area which indicates the increase of fertility in the soil beneath the species in comparison to the control area and it can be due to the litter fall or intensified biological activities of the organisms.
Asghar Ghasemi Phirouzabadi; Mohammad Jafari; Hossein Heidari sharifabad; Hossein Azarnivand; Hamid reza Abbasi
Volume 16, Issue 1 , December 2009, , Pages 1-10
Abstract
Determination of plant resistance to drought and salinity is very important for selecting the favorable plant species in rangelands. The aim of this study was to compare the salinity and drought tolerance of the two rangeland species namely puccinelia distance and Aeluropus Littoralis. In this study ...
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Determination of plant resistance to drought and salinity is very important for selecting the favorable plant species in rangelands. The aim of this study was to compare the salinity and drought tolerance of the two rangeland species namely puccinelia distance and Aeluropus Littoralis. In this study biomass production of these two species was also compared. The Experimental design of split-split plot in randomized block was excuted for the study. The main plots were allocated to the treatments of 7 and 14 days irrigation periods. The subplot were 4 level of salinity including 100, 150, 200 mmolar Cl.Na and normal irrigation water as control respectively. The morphological criterias such as water potential, wilting percentage of the plants and also dry biomass were evaluated in this study. In the context of plant anatomy, The density of stomata per unit area of leaves, vesicular structure, mesophyt tissues and epidermis were also investigated. The results showed that wilting percentage increased with increasing salinity and water deficit(drought). With increasing the time of drought and salinity stress, the weight of dry stem and total dry mass were decreased. The wilting percentage and reduction of total dry biomass in Aeluropus Littoralis was more than puccinelia distance. It was concluded that puccinelia distance is more resistante compare to Aeluropus Littoralis while Aeluropus Littoralis is more tolerate to salinity stress.
Fatemeh Sharifani; Mohammad Jafari; Hossein Azarnivand; Hamid reza Abbasi; Mahshid Sori
Volume 13, Issue 4 , February 2007, , Pages 359-367
Abstract
This paper investigates the effects of plant growth on soil quality in Sagzi plain of Isfahan in order to evaluate the effects of agriculture on desertification processes in dry lands. Inappropriate crop management is the most effective factor which is related to soil and water ...
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This paper investigates the effects of plant growth on soil quality in Sagzi plain of Isfahan in order to evaluate the effects of agriculture on desertification processes in dry lands. Inappropriate crop management is the most effective factor which is related to soil and water salinization and this is one of the important processes of desertification. Is agriculture a positive or negative factor for reclamation of saline soils? To find an answer for this question, some improved and degraded factors of desertification in Sagzi plain of Isfahan were considered. Among those common agricultural products, which of them is more effective and which of them is less effective in soil reclamation? Treatments of Medicago, Wheat and Barley were selected and compared with derelict land that was independent variable in this experiment. In order to investigate the effects of those products, soils were considered that were allocated to cultivation of these products successively at least for 5 years. Then sampling was selected in every treatment with 5 reduplication, from the depth of 0-3, 30-60, 60-90, 90-120, 120-150 centimeter. The saline features and CaCo3, EC, OM,K+, Mg2+,Ca2+, Na+, Caso4, Cl-, SAR, HCo3-, So42- investigated in every treatments. Dunkan test was applied for comparison of soil features. The results of variance analysis showed that there is significant different between treatments in different depths. Dunkan is test showed that according to the overall scores for each factor, derelict lands are least decent treatment while Weat annual agro technical lands are the most suitable one. Then this is better that agricultural products that are appropriated with condition is cultivated.
Ali Ehsani; Hosein Arzani; Mahdi Farahpoor; Hasan Ahmadi; Mohammad Jafari; Adel Jalili; Hamid Reza Mirdavodi; Hamid reza Abbasi; Mojgan Azimi
Volume 14, Issue 2 , January 2007, , Pages 249-260
Abstract
The effects of climatic factors on four dominant range land species of Markazi province, Iran, were studied. Species were Artemisia sieberi, Salsola rigida, Noaea mucronata, Stipa barbata and were monitored from 1998 to 2005. Site is located in steppe lands and called Nemati range, Akhtarabad of Saveh. ...
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The effects of climatic factors on four dominant range land species of Markazi province, Iran, were studied. Species were Artemisia sieberi, Salsola rigida, Noaea mucronata, Stipa barbata and were monitored from 1998 to 2005. Site is located in steppe lands and called Nemati range, Akhtarabad of Saveh. Climatic factors were annual rainfall, rainfall of grazing season plus rainfall of previous year, temperature, solar radiation and wind velocity. Among the main indicators, as results shows, growing season plus previous rainfalls is the most effective indicator on forage production with high and significant correlation. Total yield have positive and significant correlation with growing season rainfall and previous rainfall as well as production of Artemisia sieberi, Salsola rigida. Soil and water regime in dry and semi-dry areas, in growing season, is in a way that plants are dependent on stored moisture. Shrubs, with their deep roots, are more capable of using this moisture. Therefore stored moisture could be known as an indicator of rain quantity. Result of this research showed that rainfall indicator in growing season and previous season is a variable that plays fundamental rule in production, showing a linear relationship. Negative correlation was shown between number of sunny days, total yield and yield of two species, Salsola rigida and Artemisia sieberi.
Mohammad Jafari; Fatemeh Panahi; Hasan Ahmadi; Hamid reza Abbasi; Mohammad Musavi; Mohammad ali Zare; Ali Tavili
Volume 13, Issue 3 , February 2006, , Pages 278-283
Abstract
The desertification phenomenon with all the problems it causes , most great effect will remain in soil, so by assessing soil variations we can reach the intensity of desertification. In the Iranian model for desertification assessment some indices including EC, soil depth, soil texture and the amount ...
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The desertification phenomenon with all the problems it causes , most great effect will remain in soil, so by assessing soil variations we can reach the intensity of desertification. In the Iranian model for desertification assessment some indices including EC, soil depth, soil texture and the amount of subsoil gravel are recommended in order to assess the intensity of desertification. Here, we chose fields in different environments such as Soleyman, low desertification risk, Gazeran, desertification risk & Hossein Abad Mish Mast, already desertified field. We selected 5 profiles in each station and studied topsoil and subsoil layers in each profile and measured soil’s physical and chemical properties in the laboratory. We used spilt plots design to regard different properties of soil in each station in topsoil and subsoil and their effects on each other. In order to appoint the desertification potential in each area and in each soil unit we used the formula following: where x is score of soil indicator and x are scores of Ec, depth, and texture and subsoil gravel rate. The obtained results based on this formula indicate that the desertification of each area is moderate. Statistical analysis showed a meaningful difference for gravel and texture. The results of Duncan test selected Soleyman and Gazeran stations in one unit subset. The method used here is designed according to soil information bank and apt to arid and semiarid climate. Of its defects we can point the unreality of its scoring because there is just 4 degrees for the intensity of desertification which limits the range of scoring. Certainly in order to evaluate the desertification phenomenon we should match the results with other sections’ results. Their results will help to precede the desertification evaluation and present indices fit to Iran pattern and conditions.