Mojtabah Akhavan Armaki; Hosein Azarnivand; Mohammad hasan Asareh; Ali ashraf Jafari; Ali Tavili
Volume 18, Issue 4 , September 2012, , Pages 558-568
Abstract
Environmental stress especially water deficiency (drought) is of the most important factors in arid and semi arid regions of Iran that hugely affects plant growth especially in germination and emergence stages. To find the effects of water stress on germination properties and early growth characteristics ...
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Environmental stress especially water deficiency (drought) is of the most important factors in arid and semi arid regions of Iran that hugely affects plant growth especially in germination and emergence stages. To find the effects of water stress on germination properties and early growth characteristics of three Bromus species (B. tomentellus, B. inermis, B. persicu), a Factorial experiment based on Completely Randomized Design with four replications was conducted. Water stress treatments included -3, -6 and -9 bars, also distilled water was considered as control. Germination percentage, root length, shoot length, seedling length, root to shoot ratio, seedling dry weight, seedling fresh weight, dry to fresh weight ratio, germination rate and seed vigor were examined as germination and early growth properties of understudied species. The results showed that increase of drought stress, especially when changing from -3 to -6 bars, significantly reduced all attributes. Seedling length and seed vigor showed more decrease. Among the species, B. tomentellus showed higher germination compared to the other species. It was cleared that -6 and -9 bars potentials could be considered as favorable water stress levels to evaluate the ability of the mentioned species for germinating under drought conditions.
Hosein Azarnivand; Yaser Ghasemiaryan; Reza Yari; Mohammad Ali Zare Chahouki; Esfandyar Jahantab
Volume 19, Issue 2 , September 2012, , Pages 297-305
Abstract
The aim of this study was to investigate allelopathic activity of aerial and underground organs of mountain sagebrush (Artemisia aucheri) on seed germination features, root length, shoot length and seed vigor of Festuca ovina.For this purpose, species of mountain sagebrush were collected from Taleghan ...
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The aim of this study was to investigate allelopathic activity of aerial and underground organs of mountain sagebrush (Artemisia aucheri) on seed germination features, root length, shoot length and seed vigor of Festuca ovina.For this purpose, species of mountain sagebrush were collected from Taleghan rangelands in Tehran Province and then were dried in direct sunlight and grinded.Powder derived from aerial and underground organs to the amounts of 3, 6 and 9 grams were separately mixed with 900 grams of sand in completely randomized blocks with four replications. In each pot, 10 seeds were planted at a depth of 2-3 cm. Germination percentage, germination velocity, seed vigor, root length, and shoot length were measured. Data analysis was performed using MSTATC software and mean comparisons were carried out using Duncan's test. Results showed that there were no significant differences among measured factors. Also, the shoot and root lengths showed significant differences at probability levels of 5% and 1%, respectively. According to the results, Artemisia aucheri caused a reduction of root length in Festuca ovina.
Reza Yari; Hosean Azarnivand; Mahammad ali Zare Chahouki; Jalil Farzadmehr
Volume 19, Issue 1 , June 2012, , Pages 95-107
Abstract
In this study, the relationship between species diversity and environmental factors in the pastures in the Sarchah Amari ranglands of Birjand was investigate. For this purpose, after classification of vegetation types through physiognomy method, sampling from vegetation and environmental factors were ...
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In this study, the relationship between species diversity and environmental factors in the pastures in the Sarchah Amari ranglands of Birjand was investigate. For this purpose, after classification of vegetation types through physiognomy method, sampling from vegetation and environmental factors were accomplished in the key area of each vegetation type by random-systematic sampling. Plot size and the number of plots were respectively determined by minimal area and statistical methods. Afterward, in the key area of each vegetation type, three 300 m transects were established and 15 plots with 20 m intervals were located along each transect. Sampling of vegetation was carried out in all plots while soil samples were taken at the beginning and end of each transect from two depths of 0-30 and 30-80 cm. The list of plant species and canopy cover percentage were recorded in each plot. Percentage of soil gravel, clay, silt, sand, moisture saturation, pH, lime, organic matter, gypsum, electrical conductivity and soluble salts (sodium, potassium, chloride and magnesium) and topographic features (slope, aspect and altitude) were measured. For data analysis, species richness and evenness were calculated using different diversity indices (Simpson and Shannon -Wiener index of heterogeneity, Kamargov and Smith- Wilson as the homogeneity index). To determine the most important factors influencing variations of species diversity, principal components analysis was used. The results showed that electrical conductivity, gypsum, organic matter, slope, and sand were the most effective factors on diversity in the study area.
Asghar Farajollahi; Mohammad ali Zare Chahouki; Hosein Azarnivand; Reza Yari; BahraM Gholinejad
Volume 19, Issue 1 , June 2012, , Pages 108-119
Abstract
In this study, the relationship between environmental factors and distribution of plant communities in rangelands of Bijar protected region was investigated. Vegetation types were determined by using physiononmy method. Plot size was determined with minimal area method and after primary sampling the ...
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In this study, the relationship between environmental factors and distribution of plant communities in rangelands of Bijar protected region was investigated. Vegetation types were determined by using physiononmy method. Plot size was determined with minimal area method and after primary sampling the number of plots was determined by statistical method. In each vegetation type, sampling was done along four transects of 300 m length. 15 plots of 1m2 were established along each transect at 20 meter intervals. The type and the amount of existing species and the percentage of vegetation cover were determined in each plot. In each community, 6 profiles were dug within sampling unit. Soil samples were taken from 0-20 and 20-100 cm according to the boundary of separated horizons and type of existing plant species in study area. physiographic features including altitude, slope and aspect were measured and among soil properties, clay, silt, sand, lime, pH, EC, organic mater and gravel were measured. After collecting data, the Principal Component Analysis (PCA) was used to determine relationship between vegetation cover and environmental factors by PC-ORD software. The results indicated that there were relationships between measured factors and distribution of vegetation. Texture, gravel, lime, altitude and slope had the most influence on distribution of plant communities.
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.
Esmaeil Alizadeh; Hossein Arzani; Hossein Azarnivand; Abdol reza Mohajeri; Seyed Hassan Kaboli
Volume 18, Issue 3 , September 2011, , Pages 353-371
Abstract
Range suitability determination is considered as a step toward development and sustainable utilization of natural resources with a great significance in the world of today. Since the goats are the majority of the livestock populations using the country's rangelands after the sheep, grazing traits, adaptation ...
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Range suitability determination is considered as a step toward development and sustainable utilization of natural resources with a great significance in the world of today. Since the goats are the majority of the livestock populations using the country's rangelands after the sheep, grazing traits, adaptation and capabilities of goats were aplied in range suitability classification in the present study. The research was carried out in Ghareaghach river watershed located north-east of Semirom in Isfahan province.The framework of this research was based on F.A.O method (1991) for land evaluation. Physical factors, vegetation characteristics and water resources were considered to create three sub models including yield, water resources and soil erodibility. The final model of the range suitability in terms of range production showed that the studied rangelands were classified in three classes as moderate suitability (S2) for 2%, low suitability (S3) for 62.2% and not suitable (N) for 23.6% of the rangeland's area and 14.3% of the remaining lands was classified as non-rangelands. Among all studied land components, vegetation and forage production were identified as the first priorities to decrease land suitability for goats. Factors of distance from water sources and high slope (more than 75%) constituted the second priority for grazing suitability.
Ehssan Zandi Esfahan; Mohammad Jafari; S.Jamal.. Khajedin; Hossein Azarnivand
Volume 18, Issue 2 , September 2011, , Pages 202-218
Abstract
To study soil salinization and its amplitude due to the planting of Haloxylon ammodendron in Segzi plain of Isfahan, ordination method was used. The study was performed through stratified random sampling. Six regions were separated on the basis of different physiognomy and the year of Haloxylon ammodendron ...
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To study soil salinization and its amplitude due to the planting of Haloxylon ammodendron in Segzi plain of Isfahan, ordination method was used. The study was performed through stratified random sampling. Six regions were separated on the basis of different physiognomy and the year of Haloxylon ammodendron planting (successful and unsuccessful regions). In each region, 10 coeval individuals of Haloxylon ammodendron were selected, and plant characteristics including, height, canopy cover area, canopy cover perimeter, canopy cover diameter and basal area were measured. Three profiles were also dug in each region and five chemical soil properties i.e. EC, Na+, Cl-, K+ and SAR were measured in five horizons. Data were analyzed by means of ordination method. The results indicated that soil salinization was extremely high in successful planting regions of Haloxylon ammodendron where there was no limitation for root extension. Consequently, in these regions, the absorption of water and minerals, the growth of plant characteristics and finally the amount of litter fall to the soil surface were significantly higher than that in unsuccessful planting regions of Haloxylon ammodendron. Hence the role of Haloxylon ammodendron in soil salinization of its stratum was proved. On the other hand, the results showed that the range of soil salinization was only restricted to the first and second horizons (0-30 and 30-60 centimeters from the soil surface) and other horizons had not been affected by the growth of Haloxylon ammodendron.
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.
Azam Khosravi Mashizi; Gholamali Heshmati; Adel Sepehri; Hossein Azarnivand
Volume 18, Issue 2 , September 2011, , Pages 244-257
Abstract
Aim of this study was to introduce of the functional threshold by ecological process changes along grazing gradient to determine destroyed area.In order to prove the existence of a threshold, two linear models and three nonlinear models (exponential curve, a piecewise regression and a sigmoid logistic) ...
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Aim of this study was to introduce of the functional threshold by ecological process changes along grazing gradient to determine destroyed area.In order to prove the existence of a threshold, two linear models and three nonlinear models (exponential curve, a piecewise regression and a sigmoid logistic) were fitted on stability, infiltration and nutrient cycling data.Two nonlinear models (exponential curve and a piecewise regression) provided a much better fit to the data than the linear models. It is the evidence of threshold along grazing gradient.Results also showed that ecosystem function descended near the water point that it needs special attention of the managers.The passing of the structural threshold, increase of invasive vegetation and animal trampling were identified as the main factors in the decline of ecosystem function near the water point and occurrence of functional threshold.According to the results, the recognition of the threshold is suggested for rangeland ecosystem because defining the threshold will help land managers to prevent the occurrence of undesirable states and promote for sustainable management of rangeland ecosystems.
Hossein Arzani; Javad Torkan; Ali Nikkhah; Hossein Azarnivand; Mahdi Ghorbani
Volume 17, Issue 2 , September 2010, , Pages 191-204
Abstract
Concepts of animal equivalent has been developed to express different kind and classes of grazing animal in common form. This concept is not fixed and usually determine on the basis of live weight and metabolic weight. More than 27 sheep breeds with different body size have been adapted and grazing on ...
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Concepts of animal equivalent has been developed to express different kind and classes of grazing animal in common form. This concept is not fixed and usually determine on the basis of live weight and metabolic weight. More than 27 sheep breeds with different body size have been adapted and grazing on rangelands in different climatic zones of Iran. So it is not correct to use the same animal unit weight for all. Therefore it is necessary to determine animal unit for each breed. In this study, two herds of West Azarbayjan Makoii breed were selected, 3 and 4 years old ewes, 3 and 4 years old rams and 3 and 6 months lambs were weighted in two stages in each herd. For determination of dry matter requirement forage quality was taken into consideration. Daily requirement of animal for maintenance condition was calculated using NRC (1985) tables and MAFF (1984) equation. On the basis of results; animal unit was obtained 45.36 ± 2.75 kg which is near to animal unit weight calculated for whole country based on weight of all breeds. Daily requirement of animal was obtained 9.50 Mj metabolisable energy equal to 1.77 kg dry matter of available forage
Roja Safaian; Hosein Azarnivand
Volume 17, Issue 2 , September 2010, , Pages 331-339
Abstract
Prangos ferulacea (L.) Lindly as one of the best Iran`s range plants, is the dominant species of Iranian Jashirzar. Competitive harvesting, lack of attention to vegetative conditions and their habitats caused a disturbance on its reproduction and also the degradation of its habitats. Since the regeneration ...
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Prangos ferulacea (L.) Lindly as one of the best Iran`s range plants, is the dominant species of Iranian Jashirzar. Competitive harvesting, lack of attention to vegetative conditions and their habitats caused a disturbance on its reproduction and also the degradation of its habitats. Since the regeneration of the plant is only done in the natural habitats and through its seeds _when having in mind its deep dormancy as a member of umbelliferae family, it seems necessary to study and investigate the methods of breaking the seeds dormancy in order to protect the species . In this research in order to determine the best methods of the breakage of the seeds dormancy, the effect of some factors such as darkness, lightening, coldness, washing and temperature on the breakage of the dormancy of Prangos seeds_ collected from Fars Province pastures _is analyzed. For this purpose, a completely randomized design with three replications and five treatments was done. The results showed that treatments of coldness, lightening and 10°C temperature in compare to other treatments have significantly influenced the breakage of the species' seed dormancy. Meanwhile these methods are more important when we remind that, they are more economical and safe for the embryo in compare to other treatments such as using chemicals (specially acids). All of these together make these treatments practical methods.
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.