Naser Mashhadi; Hasan Ahmadi
Volume 17, Issue 4 , November 2011, Pages 499-517
Abstract
The results of wind dynamic are transport of soil or sediment particles and subsequently evolution of desert landforms according to the intensity of either erosion or sedimentation process.Geology, geomorphology and climatology conditions of the Khartouran region create a special situation on the closed ...
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The results of wind dynamic are transport of soil or sediment particles and subsequently evolution of desert landforms according to the intensity of either erosion or sedimentation process.Geology, geomorphology and climatology conditions of the Khartouran region create a special situation on the closed basin of Dasht-e-Kavir. It is evident that the ecosystem balance of the region is affected by anthropogenic exploitation and wind activity, so this area has a geoecological structure with special features. The Khartouran Erg is resulted of wind activity on sand sources. The study area is located on the southwest of Sabzevar city with a total area about 200000 hectares. The study was carried out based on topographic, geologic maps, satellite images, aerial photographs, field observation and sampling. Based on the information and data, the study area was divided into grid cells of 3 km × 3 km. Surface soil or sediment of corner points of each grid was sampled (214 points). The results of granolometry analysis of soil or sediment samples were presented in seven maps. These maps show grain size distribution and consequently determine sand supplement potential of each point in different wind velocities.The granulometry analysis of samples showed that particle size with a range of 0.063 to 0.150 mm (the most vulnerable sand particle size to wind erosion) comprised the most percentage of distribution. Based on the results it may be concluded that these regions were affected by wind erosion in the past more rather than of current time and Khartouran Erg is result of wind activity in the past. Currently, the rate of sand movement intensity and the balance between erosion and sedimentation are dominant factors in shaping geomorphologic facies (Aeolian landforms).
Asghar Kohandel; Hossein Arzani; Morteza Hosseini Tavassol
Volume 17, Issue 4 , November 2011, Pages 518-526
Abstract
Different grazing intensities change the chemical and physical properties of soil and plant composition of rangelands. Accordingly, effect of livestock grazing intensities on soil and vegetation characteristics were investigated in the southeastern of Hashtgerd using Principal Component Analysis. Principal ...
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Different grazing intensities change the chemical and physical properties of soil and plant composition of rangelands. Accordingly, effect of livestock grazing intensities on soil and vegetation characteristics were investigated in the southeastern of Hashtgerd using Principal Component Analysis. Principal Component Analysis is a statistical method for defining new variables based on a linear combination of original variables. Three 5-ha areas were selected in the study area under treatments of no, moderate, high and continuous grazing intensities. Afterward, vegetation and important physical and chemical soil characteristics including moisture, specific gravity, soil porosity, infiltration, mechanical resistance, nitrogen, phosphor, potassium, pH, EC, soil texture and organic matter were measured in three grazing treatments for two years (2004 and 2005). According to the results, increase of grazing intensity increased forbs while grasses and shrubs decreased. Among soil properities, soil porosity and Mechanical resistance decreasid and pH, EC and K had the highest relationship with grazing intensity.
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.
Reza bagheri; Sedegheh Mohammadi
Volume 17, Issue 4 , November 2011, Pages 538-548
Abstract
Allelopathy is interaction effects of plants on each other through extracted chemical compounds. This phenomenon that has not been considered in range improvement is of important concerns in rehabilitation of rangelands. In this study, we tested allelophatic effects of Artemisia sieberi ongermination ...
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Allelopathy is interaction effects of plants on each other through extracted chemical compounds. This phenomenon that has not been considered in range improvement is of important concerns in rehabilitation of rangelands. In this study, we tested allelophatic effects of Artemisia sieberi ongermination percentage, stem fresh weight and root fresh weight of three species (Agropyron desertorum, Agropyron elongatum and Atriplex canescens) that are widely used in range improvement. Powder of Artemisia sieberi (stem, leaf and root) collected from natural habitats in flowering stage (end of Novambr) was mixed with different concentration levels ( 0%, 0/1 %, 1% and 10 %) in four replicetions and was planted in sand under laboratory condition based on completly rondom design. After putting 25 live seeds of the mentioned species in each pot, three variables as germination percentage, stem fresh weight and root fresh weight were measured and then ANOVA and Duncan's multiple range tests were applied to analyze the data in SPSS software. According to the results decrease rate of germination percentage in comparison to control treatment were as follows :in Agropyron desertorum 60 and 83% from 1 and 10 % leaf concenterations respetively, in Agropyron elongatum 84/2% from 10% leaf concentration and in Atriplex canescens 83/3 and 88/9% from 1 and 10% all tissues concentrations respectively. Also our finding showed that stem weight of Agropyron elongatum was decreased to 48 and 94/5%, respectively in 1 and 10 % of leaf tissue and root weight of Atriplex canescens was decreased to 82/2 and 88/1% in 1 and 10 % of all tissues in comparison to control treatment. According to results of the study under laboratory condition, rehabitating of Artemisia sieberi sites through using the mentioned species probably will not be successful.
Aazam Khosravi Mashizi; Gholamali Heshmati; Aadel Sepehri; Hossein Azarnivand
Volume 17, Issue 4 , November 2011, Pages 549-563
Abstract
Considering previous studies which showed no significant relation between the distance from water point and total vegetation cover, in current research plant species were classified based on life forms (shrub, bush, perennial grass, perennial forbs and annual forbs) and palatability classes (I, ...
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Considering previous studies which showed no significant relation between the distance from water point and total vegetation cover, in current research plant species were classified based on life forms (shrub, bush, perennial grass, perennial forbs and annual forbs) and palatability classes (I, P and PI). One way ANOVA was applied to determine the variations with distance from water point 8 main directions. Results showed that 8 main directions had no significant effect on vegetation cover and palatability classes of studied life forms. While life forms and palatability classes had different reactions to grazing according to the distance from water point. As shrubs, bushes, perennial grasses and palatability class I increased and annual forbs and palatability class PI decreased with distance from water point. Perennial forbs and palatability class P had uniform distribution. Using results of Duncan multiple range test a critical area was determined at 400 m distance from water point. In the mentioned critical area, shrubs and bushes showed a decrease in vegetation composition while annual forbs increased. Palatability class I also was eliminated in this area. According to the variations in perennial grasses and palatability classI, very sensitive to grazing, it can be concluded that grazing intensity had been very severe at a distance of 800-1000 m from water point.
Ebrahim KAzemi; Amrali Shahmoradi; Mohsen Padyab; Ardeshir Shafiee; Yaser Ghasemi Aryan
Volume 17, Issue 4 , November 2011, Pages 564-574
Abstract
Autecology consederd as study a plant species behaviour and function and also determining its relationship with other biotic and abiotic components includes an important part of ecological studies in natural resources science. In the current research, autecology of Dorema aucheri, ...
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Autecology consederd as study a plant species behaviour and function and also determining its relationship with other biotic and abiotic components includes an important part of ecological studies in natural resources science. In the current research, autecology of Dorema aucheri, a perennial plant from Apiaceae family, was studied in range ecosystems of Kohgiloye and Boyerahmad. First of all vegetation map was provided using 1:50000 topographic maps and all characteristics including topography, climate, soil, and also companion species, root system, phenology, regenerarion, preference value, chemical compounds and frequency were studied. According to the results, Dorema aucheri grows in an elevation range of 1600 to 3400 m above sea level and in semi arid and moderate mediterian climates. The highest density of Dorema aucheri was recorded at 2300 to 3000 m above sea level. Soil texture in the study area was silty clay loam, silty clay, clay, silty loam and loam. Soil EC differed from 0.21 to 0.5 ds/m and a pH range of 7.5 to 8.2 was obtained. Average annual precipitation is 750 mm and temperature differed from -11 to 35 centigrade degree. Vegetative growth starts in early March and ends in early April. Its flowering stage is from mid April to May. Seed ripening stage is in mid July and no autumn growth was recorded. Root spreads in vertical (>200cm) and horizontal (>150cm) dieractions. Despite this plant is not palatable, it is used by livestock in absence of other palatable species. Human also utilizes this species as food or medicinal purposes.
Mohammad mahdi Fatahi; Mohammad Darvish; Hamid reza Javid kia; Mahdi Adnani
Volume 17, Issue 4 , November 2011, Pages 575-588
Abstract
Desertification is defined as the reduction of biomass potential and degradation of environmental resources and ecosystems which affects regional and cross-regional levels of human life.Assessment and mapping of desertification in Daryache Namak watershed with a 1614176 hectares area were considered ...
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Desertification is defined as the reduction of biomass potential and degradation of environmental resources and ecosystems which affects regional and cross-regional levels of human life.Assessment and mapping of desertification in Daryache Namak watershed with a 1614176 hectares area were considered as the aim of the current research. Desertification aspects were determined from vegetation degradation, water and wind erosion, quantitative and qualitative loss of water resources and soil salinization using FAO-UNEP method.Desertification was classified by overlaying and averaging of current status and natural capacity and all maps were made in GIS. According to the results, vegetation degradation (23.25%) and water resources degradation (59.63%) included the most area in current status and natural capacity of the study area respectively. Desertification total risk was also classified and mapped considering current status, natural capacity and human impacts and results indicated that 23.51, 76.47 and 0.02 percent of this watershed located in moderate, severe and very severe desertification classes respectively.
Ali Mohammad Asaadi; Ali reza Dadkhah
Volume 17, Issue 4 , November 2011, Pages 589-603
Abstract
In this study, floristic composition and species richnessof Pelmiss summer rangeland located between Bojnord and Esfarain were studied through flora collection and using Whittaker plots in exclosure and degraded rangelands. The main goals of this study were to determine floristic composition and species ...
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In this study, floristic composition and species richnessof Pelmiss summer rangeland located between Bojnord and Esfarain were studied through flora collection and using Whittaker plots in exclosure and degraded rangelands. The main goals of this study were to determine floristic composition and species richness in different vegetation types and also effects of slope and aspect on species richness. The data were analyzed by using linear and group regression model. According to the results, two relationships i.e. (HE > CH > TH > GE >PH) and (Forbs > Woody plant > Grasses) were found in view of biological types and growth form respectively. Species richness in exclosure area was more than that in degraded area. Species richness in western and northern slopes was also higher than that in eastern and southern slopes. In general, it can be concluded that vegetation of the study area is mostly of perennial plant species, a characteristic of mountainous areas with cold climate in altitudes.
Maryam Rezashateri; Aadel Sepehri
Volume 17, Issue 4 , November 2011, Pages 604-614
Abstract
This research was carried out to study the effect of livestock grazing on dynamics of vegetation patches in rangelands of Incheh Boroun, North Gorgan plain. To achieve this goal, the dynamic parameters including the length of vegetation patches and bare area distances between consecutive vegetation patches ...
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This research was carried out to study the effect of livestock grazing on dynamics of vegetation patches in rangelands of Incheh Boroun, North Gorgan plain. To achieve this goal, the dynamic parameters including the length of vegetation patches and bare area distances between consecutive vegetation patches inside and outside the enclosure were measured. First of all, a random point was selected outside the exclosure as starting point and then 11 transects with 50 meters length were placed in a randomized sequential order. The length of vegetation patches and free vegetation spaces were recorded along each transect. Sampling inside the exclosure was done similarly through setting up six 50-meter transect Results showed significant differences in length of vegetation patches, inter patches and ratio of vegetation patches length to inter patches length in both studied regions. Overgrazing outside the exclosure was considered for this result. Since environmental stresses reveal their impacts through changing the shape, frequency and size of vegetation patches, it seems that studying the length of vegetation patches and inter patches has high accuracy and can be done with relatively less time and costs. In addition, it could well represent dynamic changes of plants in response to environmental stresses and desertification process.
Sadegh pourmoradi; Aliashraf Jafari
Volume 17, Issue 4 , November 2011, Pages 615-623
Abstract
7 accessions of white clover (Trifolium repense L.) were evaluated in view of forage yield and quality traits in rangelands of Mazandaran province. A randomized complete blocks design with three replications was applied in three consecutive years (2003-2005). The data were collected for persistency (based ...
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7 accessions of white clover (Trifolium repense L.) were evaluated in view of forage yield and quality traits in rangelands of Mazandaran province. A randomized complete blocks design with three replications was applied in three consecutive years (2003-2005). The data were collected for persistency (based on gerund cover) and dry matter yield. Six quality Traits as: crude protein (CP), dry matter digestibility (DMD), water soluble carbohydrates (WSC), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF) and total ash were measured using Near Infrared Reflectance (NIR) technology. DMD-yield, WSC-yield and CP- yield were also calculated based on the equations. In the first year (establishment), no harvest was made, but in the second year the forage yield was harvested. In the third year, the varieties had not enough growth and therefore no harvest was made. Data were analyzed and the means of treatments were compared using Duncan¢s multiple range test. According to the results the most vegetation cover persistency was recorded for Chiftan and Tahora, Aran, Avoca, and Tara were placed in next orders respectively. The highest CP-Yield, DMD-Yield and WSC-yield, were also recorded for the varieties of Aran, Grassland, Tara and Chiftan respectively. Mean comparison of dry matter yield also showed that the varieties of Aran, Grassland, and Tara with an average of 2324, 2005 and 1909 kg ha-1 were classified in similar group and had the highest forage yield. Considering all studied factors together (persistency and forage dry matter, CP, DMD and WSC yield), Aran and Tara were identified as the superior accessions for forage production in summer rangelands of Mazandaran province.
Motahareh Esfandiari; Mohammad ali Hakimzadeh Ardakani
Volume 17, Issue 4 , November 2011, Pages 624-631
Abstract
Desertification is one of the most important problems in arid and semiarid lands of the world. Rapid growth of human population and increasing of cultivation cause the degradation of soil and water resources. In the other hand, the reclamation of soil is time consuming and very expensive; therefore, ...
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Desertification is one of the most important problems in arid and semiarid lands of the world. Rapid growth of human population and increasing of cultivation cause the degradation of soil and water resources. In the other hand, the reclamation of soil is time consuming and very expensive; therefore, it is necessary to know the destruction factors of soil and its effects on desertification. In order to evaluate soil degradation in agricultural lands of Abade-Tashk, the IMDPA model was used. Four soil indexes: Electrical Conductivity, percent of gravel, depth and texture were applied in this model. For evaluation of soil indexes, randomized network sampling was used and then each index measured according to its effect in the model. The geometrical mean of indexes were calculated using GIS software. Desertification map of each index was prepared and then the current situation of each index obtained. The final map of desertification was prepared by combination of the index maps using mean geometrical method. The results showed that 47% of total area (2212 ha) located in low class of desertification, 43% (2019 ha) in medium class and 10% (467 ha) in high class of desertification.
Hojat... Khedri Gharibvand; Ghasemali Dianati Tilaki; Mansur Mesdaghi; Manuchehr Sardari
Volume 17, Issue 4 , November 2011, Pages 532-545
Abstract
Camphorosma monspeliaca is one of the rare species in Chaharmahal va Bakhtiari Province with a distribution of 3500 ha in Doto-Tangsayad. In the current study, distribution of Camphorosma monspeliaca in the province, vegetation and companion species, phenology and relationship ...
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Camphorosma monspeliaca is one of the rare species in Chaharmahal va Bakhtiari Province with a distribution of 3500 ha in Doto-Tangsayad. In the current study, distribution of Camphorosma monspeliaca in the province, vegetation and companion species, phenology and relationship between plant and environmental factors were studied to investigate some ecological characteristics. Although Camphorosma monspeliaca has a large distribution in the studied area, the best distribution pattern was seen in southern and northern aspects as dominant or companion species. Camphorosma monspeliaca is companion with other species in different aspects. According to the results, average of plant parameters differed in different aspects as the most canopy cover and density of Camphorosma monspeliaca were recorded in southern aspect.In view of forage quality, protein content and digestibility of the mentioned species are high. Camphorosma monspeliaca can be established in none saline soils (Ec < 2dsm-1) and alkali soils (7.5<pH<8.5) with a soil texture of clay, clay loam, loam and calcareous soils (20-30%) having a low content of organic matter and gypsum.Among studied elements C, N, Ca and Mg were much higher in the soil under Camphorosma monspeliaca vegetation due to the need of range species and easy access to these elements. In comparison to K and P, Na was higher in Camphorosma monspeliaca because of high sodium adsorption ability in plants of Chenopodiacea with a C4 photosynthetic pathway.In general, study of the mentioned species is essential to consider its multiple uses.