Gholam reza Zahtabian; Mohammad Jafari; Fatemeh Movahedian; Maryam Naeemi
Volume 16, Issue 4 , January 2010, , Pages 468-480
Abstract
Nowadays, desertification as a great problems affect most of the countries in the world especially developing countries. Desertification phenomenon that occurs in arid, semi-arid and dry semi-wet regions will reduce the land potential. For evaluation and mapping of desertification many researches have ...
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Nowadays, desertification as a great problems affect most of the countries in the world especially developing countries. Desertification phenomenon that occurs in arid, semi-arid and dry semi-wet regions will reduce the land potential. For evaluation and mapping of desertification many researches have been conducted leading to regional and local models. In this study MEDALUS model because of easy style and data accessibility and also compatible with the effective indices on land degradation was applied for land degradation intensity mapping with emphasis on soil criterion in Hablerood catchment. So in this study, soil criterion and 6 indices including: EC, Rock fragment, depth and texture of soil, slope, and percentage of soil organic matter were assessed. At the first work units was prepared; in each work unit, one soil profile was dogged (10 profiles) and desired indices were measured in laboratory. Finally, sensitive map of region was extracted using assigned score to each index and geometric average of all indices. Data were analyzed by using spss software and analysis method of various one- way ANOVA. The results showed that, about 4.16 percent of the area is classified under low class and in the level of 0.05 there was no significant differences between indices, and the only significant difference was in the gravel percentage of soil surface in 0.01 levels.
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.
Morteza Akbarzadeh; Mohammed Reza Moghadam; Adel Jalili; Mohammad Jafari; Hossein Arzani
Volume 13, Issue 4 , February 2007, , Pages 324-336
Abstract
The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and soil degradation in many natural rangelands of Iran. Grazing prevention is one of the rangelands rehabilitation methods, which is effective in renovation of rangelands. The effect of 24 years of grazing ...
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The pressure of livestock grazing and overall utilization of rangelands have caused vegetation and soil degradation in many natural rangelands of Iran. Grazing prevention is one of the rangelands rehabilitation methods, which is effective in renovation of rangelands. The effect of 24 years of grazing protection were studied on vegetation dynamics of Kuhrang region, in two years growing seasons (2003 and 2004). Parameters from rangelands characteristics were collected and analyzed. Results showed that after 24 years livestock exclusion in Kuhrang, total inside canopy cover was higher than outside (P<0.01). Grasses and forbs were higher inside than outside (P<0.01), but shrubs were not significantly different (P>0.05). Over half of inside canopy cover belonged to decreasers and increasers, which were little or negligible outside of exclosure and 95 percent of outside plant composition belonged to invaders. Most desirable species had greater inside cover than outside(P<0.01). Klucia odoratassima, Scorzonera calyculataand Delphinium cyphoplectrumhad greatest inside canopy cover, than other forbs. More than half of inside and 95 percent of outside cover referred to decreasers and increasers. Approximately 38 and 1.2 % of inside and outside forage production belonged to decreasers and increasers respectively. Regeneration was higher outside of exclosure in Astragalus adscendens, in first year. Litter was higher inside and bare soil outside the exclosure (P<0.01). Inside and outside range condition was good and very poor, respectively.
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.
Daruosh Ghorbanian; Mohammad Jafari
Volume 14, Issue 1 , January 2007, , Pages 1-7
Abstract
In this study one site with good coverage of Salsola rigida species selected in desert region of Shahrood area. Four plots of 100 m2 were chosen in this site and two soil profiles were digged in each plot; one profile under Salsola rigida plants and another in the space between this species. Soil samples ...
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In this study one site with good coverage of Salsola rigida species selected in desert region of Shahrood area. Four plots of 100 m2 were chosen in this site and two soil profiles were digged in each plot; one profile under Salsola rigida plants and another in the space between this species. Soil samples were collected from three depth of 10-25 cm, 10-25 cm and>25cm. For asessing elements of biomass and their effects on the soil, plant sample were analysed in laboratory. Results indicated that organic matter percentage as well as N, K and HCO3 increased significantly. An increase of Ec, Caco3 and Na are the main detrimental factors for expanding Salsola rigida species.
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.