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Rangeland Science - Volume:1 Issue: 2, Winter 2011

Journal of Rangeland Science
Volume:1 Issue: 2, Winter 2011

  • تاریخ انتشار: 1390/06/15
  • تعداد عناوین: 10
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  • M.T. Gaemi, M. Akbarzade, Sh. Abedi Page 75
    The study of the exclosure effects on the vegetation changes under grazing and non-grazing conditions in the rangeland areas has particular importance in the rangeland improvement and revivification projects. The research was accomplished in semi-steppe KhoyBilehvar area, from 1999 to 2005. Vegetation cover was annually measured within fixed plots during transact. The results showed that during nine years of research, on KhoyBilehvar exclosure, the total canopy cover has increased inside the exclosure, and the highest increase was observed in the perennial grasses (more than 3.5) and perennial Forbs (more than 2.5). Outside the exclosure, the total vegetation cover was almost constant and changes were less in vegetation cover types. Within the exclosure, some desirable species appeared consisting almost 19% of vegetation composition. Medium species proportion in the plant composition increased to more than two times and undesirable species decreased by half. Whereas, outside the exclosure, scarce desirable species and medium species of vegetation ratio has increased a little. The vegetation average of annual species during the study within exclosure is more than outside and the vegetation average of forbs inside and outside the exclosure is more than annual grasses. Nine year research in Bilehvar exclosure showed that the correlation between precipitation changes and vegetation cover was significant in the most species.
  • M. Zaremehrjardiri Page 85
    The objective of this study was to assess the relationship between vegetation, landform and physicochemical properties of soil. At the first terrain map unit were provided using the landsat thematic mapper (TM) satellite images, aerial photograph, topographical and geology map. Field sampling was done in the representative area using plot sampling. 104 plots 100 m2 were sampled in each plot landform parameters (slope, elevation, aspect), percentage of vegetation cover, were measured and stoniness and browsing damage were estimated and one soil sample was taken for measuring EC, pH, and texture. Relationship between vegetation and environmental factors was based on correlation analysis, box plot and Kruskal Wallis test (multiple comparisons). Correlation analysis showed a positive correlation between vegetation cover with slope and elevation and a negative correlation with EC. Based on the Kruskal Wallis test there was significant difference in vegetation cover between different geopedological map units. No significant relationships were found between vegetation cover and other soil properties such as pH and texture.
  • H. Azarnivand, A. Farajollahi, E. Bandak, H. Pouzesh Page 95
    Soil physical properties have an important role on vegetation growth through affecting the development of root system. The aim of this study was to investigate the trampling effect of livestock grazing on soil physical properties and vegetation cover changes. The experiment was conducted on three range condition sites (Reference, Key and Critical area) with ten frequencies in Hosseinabade Kudistan in 2009. Soil physical characteristics consist of humidity, bulk density, porosity and aggregate stability index. In this study remarked soil cover changes in three mentioned regions. The results showed that soil moisture reduced from reference to critical area. Soil bulk density was the lowest in reference area and the highest in critical area. Reference site had the highest soil porosity while the soil porosity reduced in critical area. However, as the density of grazing increased, soil bulk density increased and soil moisture, soil porosity, aggregate stability index and vegetation cover percent decreased. Bare soil percentage was the highest in critical region. According to the results of this research, the grazing seems caused to major changes in the physical properties of the topsoil. Since the region has high ecological potential, if the intensity of grazing would be in a moderate level, the region soil will be able to compensate the negative aspects of livestock trampling.
  • Zh. Toupchi Page 103
    Arshadchamani rangelands are placed in the north foothill of Sahand Mountain and near Kandovan Village. Therefore, it has plant diversity and economical values. In this region, medicinal plants are cut and sold by the stores with non-standard packaging without scientific name. Regarding the economical value of medicinal plants and thereby the investment necessity on these valuable resources for using in chemical, pharmaceutical and food industries, the collection and identification of these plants could be useful. Collection and identification of plants in the region were carried out during two years. 256 collected species were identified in herbarium and then medicinal plants were separated by the scientific references. During this project, 95 species of medicinal plants belonging to 78 genus and 32 families were identified. The highest number of medicinal plants were related to Lamiaceae (17 species), Asteraceae (11 species), Brassicaceae (10 species), Fabaceae (9 species) and Apiaceae (7 species). The life form of medicinal plant species was determined by Raunkier's method and they are including 57.89% Hemicryptophytes, 28.42% Therophytes, 7.36% Chamaephytes and 5.26% Geophytes. Six medicinal vegetation types were recognized in the are: Ziziphora clinopoioides Lam. Thymus kotschyanus Boiss. And. Hohen.,Urtica dioica L., Alcea flavovirens (Boiss. and Buhse) Iljin, Stachys lavandulifolia Vahl, Cichorium intybus L., Achillea willhelmsii C. Koch, Stachys inflata Benth., Peganum harmala L., Rosa domescena L. were economically very important.
  • G. A. Heshmati, V. R. Squires Page 111
    Rangeland ecosystems shift across dynamic thresholds between different ecological states in response to natural or human-induced factors. These different ecological states are the result of interactions among climate, soils, grazing history, and management practices. The notion of a single ‘‘pristine’’ final state is only conceptual in nature, and because of this, dynamic thresholds and the effects of various processes on ecosystem structure and function must be incorporated into decision-making. Rangeland managers should have a working knowledge of the key ecological processes in each state, and the processes that drive a system across a dynamic threshold from one state to another. To do this they need indicators for critical decision-making points. It is essential to identify the thresholds of an ecological transition state and ecological indicators of these states. The criteria of these ecological indicators might be measurable, sensitive to stress on the system, have a known response to disturbance and easy to measure. The state and transition approach may offer an appropriate framework as an aid for decision making and can be used to highlight ‘‘management windows’’ where opportunities can be seized and hazards avoided. China’s vast drylands are used as a case study and the potential to apply these principles is discussed.
  • R. K. Mandloi, Rajesh Gupta, A. Rehman Page 121
    The machine to be designed and developed with a view to resolve one of the irksome problems of this institute has been facing every year. This institute is surrounded by vast non- fertile land area of about 200 acres, which becomes widely occupied by numerous breads of bushes and shrubs during post-rainy season. Due to this unwanted proliferation of such verdant institute gets abysmal look and that dumps off massive fund every year to get rid off it. The shrubs cutting machines comprises a main body (chassis) with two wheels and handle to provide movement in the field. One power unit (small S.I. engine) is mounted on this to give power for the cutting blades through small transmission mechanism. The cutting blades are mounted on a small shaft. Which actually perform the cutting operation? We intend to develop a machine which would provide better cutting action of bushes with low capital and operational cost. With reference to literature available there are many types of lawn mowers, bush cutters and lawn tractors are exist in the market, which may not fulfill the capital and operational cost criteria. The main concentration of our design is the cost and operational ease. During design, development and fabrication the machine was undergone several laboratory. Field tests like; determination of torque and force analysis, load and speed test on design specifications (for shaft, gear and bearings), impact test, balance test and finally cutting output test. After testing we succeed to have a satisfactory performance, though it requires further more improvements which can be done in due course of time in stage II of the project.
  • Ariapour A., M. Nassaji Zavareh Page 125
    Evaporation is one of the most important components of hydrologic cycle. Accurate estimation of this parameter is used for studies such as water balance, irrigation system design, and water resource management. In order to estimate the evaporation, direct measurement methods or physical and empirical models can be used. Using direct methods require installing meteorological stations and instruments for measuring evaporation. Installing such instruments in various areas requires specific facilities and cost which is impossible to be specified. Pan evaporation is one of the most popular instruments for direct measuring. In this research, by using daily temperature, relative humidity, wind velocity, sunshine hours, and evaporation data in meteorological station and neural network model, daily evaporation is estimated. Network training using daily data takes three years and network testing takes one year in which data is standardize for training and testing the model. In this model, a feed forward multiple layer network with a hidden layer and sigmoid function is used. The results show the suitable capability and acceptable accuracy of artificial neural networks in estimating of daily evaporation. Best model for estimation of evaporation is ANN (5-4-1), it have MSE 0.006716 and R2 0.725398. Artificial neural networking is one of the methods for estimate evaporation. In this method can use in any area that have only maximum and minimum data for estimate evaporation.
  • S. Kumar, K. H. P. Reddy, P. Srinivasa Rao, P. Sanjana Reddy, Belum V. S. Reddy Page 133
    Generation mean analysis was carried out to estimate the nature and magnitude of gene effects for sugar yield and its component traits in sweet sorghum [Sorghum bicolor (L.) Moench. Six basic generations, namely P1, P2, F1, F2, BC1P1, BC1P2 of four crosses involving seven diverse parents were evaluated in rainy 2009. The mean performance of the F1 in all the crosses indicated dominant gene effect for all the characters. Simple additive-dominance model indicated presence of epistatic interaction. High positive additive × additive interaction effects were found in all the crosses. Higher magnitude of dominance and dominance × dominance gene interactions which were found minimizes the expression of heterosis leading to non-exploitation of crosses with duplicate epistasis. Reciprocal recurrent selection and/or biparental mating in early segregating generations has been suggested for development of high sugar yielding genotypes in view of the genotypes studied.
  • Gh. Chamapira, S. Taghavi Goudarzi Page 143
    In recent years, the occurrence of water and wind erosion in different parts of country due to the changes of land use from the forest and pasture into the agricultural and also construction of communication lines have increased. The study and research on this phenomenon, the effective factors in creating them and also identification of geomorphology facies types are necessary to prevent the waste of water and soil resources and their damages. In this study, in order to homogenize the studies and prevent the disperse works; we have tried to generate a base map based on geomorphological one. Thematic maps such as lithology and slope erosion facies map were also combined and finally obtained a homogeneous unit map (work units) which has a special place in natural resources studies. Considering the characteristics of each of these homogeneous units, there should be a special planning to protect and restore them. Therefore, considering the nature of this study, it can be a basic platform and be used in other studies. According to researches, 12 geomorphological facies were identified in the region. These facies are in mountain and pediment units; so three types of pediments including erosion, appendage and covered ones were distinguished in pediment unit. Different facies with specific characteristics were determined in each of these types. Finally, considering the natural power (potential) of facies and current status of land use, a management program was suggested.
  • R. Talaei, A. Jafari Ardakani, F. Azimi, R. Bayat, M. Parehkar Page 153
    One of the main resonator factors in watershed soil erosion is inappropriate land management including conversion of pasture land to dry-land farming. Unfortunately, the changes of Gara Su watershed usages have been very common. Thus, in order to understand the influence of land use on runoff rate and soil loss, soil losses were investigated and determined under both pasture and dry-land agricultures at sub-watershed of Dojag chay in southern west Qara Su Basin (within Ardebil province). In this Research, using a drop maker rainfall simulator device, 18 treatments under the said watershed were conducted using an artificial rain with the intensity of 6 mm/ min for 6 minutes and soil loss rate was measured due to the rainfall in two user types in dry-land and rangeland under natural humidity conditions and approximately the same as the raining season in three slope classes of 5 to 12, 12 to 20 and greater than 20. The results showed that with the cultivation, cultivated soils get empty and their porosity and permeability increase so, with the increase of water penetration ability, their runoff compared to the pasture lands starts with delay. Comparing the amount of runoff shows that after runoff gets started in rain-fed agriculture lands, the flowing speed and amount of water become more than those of pasture lands and the statistical analysis also verified the significant relationship, especially in slopes of more than 20% between the amount of soil loss and land use. The soil loss under rain-fed agriculture was 8.8 times more than the pasture. As the soil loss was compared for different slope classes of 5-12, 12-20, and more than 20 slope percent, the results indicated that the soil losses under rain-fed agriculture were 4.5, 5.6, and 12 times more than the pasture. The study results, therefore, can be utilized for proper management of area through devoting necessary attention into land uses.