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.
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.
Hamid Torang zar; Qavam aldin Zahedi; Mohammad Jafari; Hojat ... Zahedi pur
Volume 18, Issue 3 , September 2011, Pages 384-394
Abstract
The main objective of the present study was finding spatial relationship model of the plant species composition to physico-chemical soil variability, in north-west of Mighan Desert in Arak. According to the condition of the studied habitats, the study was based on a survey of three identified vegetation ...
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The main objective of the present study was finding spatial relationship model of the plant species composition to physico-chemical soil variability, in north-west of Mighan Desert in Arak. According to the condition of the studied habitats, the study was based on a survey of three identified vegetation types. Sampling method for vegetation study was randomized systematic. Quadrate size was determined for each vegetation type using minimal area method. Soils sample were taken from 0-20 and 20-100 cm depths. The measured soil factors included, EC, organic matter, texture, lime, gypsum, available moisture, pH, and soluble ions (Ca2+, Mg2+, Na+, Co32- , H-Co3, Cl-, So42). The classification of vegetation was analyzed by TWINSPAN and DCA methods. To determine the most edaphically effective factors in distribution of vegetation, PCA and CCA were applied. Three main vegetation groups were identified by TWINSPAN analysisand DCA. The result indicated that soil salinity, soil texture, lime, and soluble ions (Mg2+, So42) played the main role in the distribution of plant species.
Omol banin Bazr afshan; Mohsen Mohseni saravi; Arash Malekian; Abalfazl Moeini
Volume 18, Issue 3 , September 2011, Pages 395-407
Abstract
Drought is defined as the continuous and abnormal moisture deficit. The term of continuous means continuation of deficit and the term of abnormal means deviation of favorite index of natural condition from the mean. In every drought study four main characteristics are considered: severity, duration, ...
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Drought is defined as the continuous and abnormal moisture deficit. The term of continuous means continuation of deficit and the term of abnormal means deviation of favorite index of natural condition from the mean. In every drought study four main characteristics are considered: severity, duration, frequency or return period and areal extent. The objective of this investigation is mapping drought severity in Golestan province. For this purpose, Standardized Precipitation Index (SPI) was used for drought monitoring in some meteorological stations located in Golestan province. This index was computed in a period of 25 years precipitation data (1975-2000) at four different time scales including 6,9,12, and 24 months. Consequently, the most sever drought in 6 month time scale was observed in Saliantapeh station while the highest severity in 9, 12, and 24 time scales was observed in Polejadeh station. The aerial extent SPI values for the most severe drought condition in different time scales were classified in Golestan province using geostatical techniques. The results showed that the area affected by drought decreased with increasing drought duration and the condition of drought in the province had west-east direction
Elham Fakhimi Abarghoie; Mansoor Mesdaghi; Parviz Gholami; Hosein Naderi Nasrabad
Volume 18, Issue 3 , September 2011, Pages 408-419
Abstract
One of the main objectives of ecosystem managements is preservation of diversity. By measuring the diversity and evenness of the species, the necessary management recommendations will be presented. In this research, the effect of slope, aspect and elevation on richness and evenness of plant species were ...
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One of the main objectives of ecosystem managements is preservation of diversity. By measuring the diversity and evenness of the species, the necessary management recommendations will be presented. In this research, the effect of slope, aspect and elevation on richness and evenness of plant species were evaluated at steppe rangelands of Nodushan, in Yazd province. Systematic random sampling method was applied and the size of plot was determined by minimal area. The results showed that elevation had significant effects on diversity and frequency of species and moderate elevation ranges of 2400- 2600 had higher richness and evenness. Slope range had also significant effects on diversity and frequency and high slopes (30- 50%), had the highest diversity. Aspects had no significant effects on indices of diversity.
Saleh Arekhi; Mostafa Adibnejad
Volume 18, Issue 3 , September 2011, Pages 420-440
Abstract
Land use classification using remotely sensed images is one of the most common applications in remote sensing, and many algorithms have been developed and applied for this purpose in the literature. This study investigates the efficiency of Support Vector Machines algorithms in image classification. ...
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Land use classification using remotely sensed images is one of the most common applications in remote sensing, and many algorithms have been developed and applied for this purpose in the literature. This study investigates the efficiency of Support Vector Machines algorithms in image classification. Support Vector Machines (SVMs) are a group of supervised classification algorithms of machine learning that have been used in the remote sensing filed. The classification accuracy produced by SVMs may show variation depending on the choice of the kernel function. In this study, SVMs were used for land use classification of Ilam dam catchment using Land sat ETM+ data. The classification using SVM method was implemented automatically by using four kernel types, linear, polynomial, radial basis, sigmoid and the results were analyzed thoroughly. Results showed that SVMs, especially with use of radial, polynomial and linear function kernels, outperform the maximum likelihood classifier in terms of overall (about 10%) and kappa coefficient(about 15%) accuracies. So, this study verifies the efficiency and capability of SVMs in classification of remote sensed images.
Marzieh Abassi; Sadaat Feiznia; Hamid reza Abassi; Uones Kazemi; Ahmad Gharanjik
Volume 18, Issue 3 , September 2011, Pages 441-451
Abstract
Source identification of sand dunes is of particular importance in projects of wind erosion control. In this study, the map of geomorphology and inventory map of sand dunes were prepared for five regions of Baluchestan under wind erosion using aerial photos, satellite images and Arc-View ...
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Source identification of sand dunes is of particular importance in projects of wind erosion control. In this study, the map of geomorphology and inventory map of sand dunes were prepared for five regions of Baluchestan under wind erosion using aerial photos, satellite images and Arc-View and Arc-GIS soft wares. Then, 28 samples were collected based on the form of sand dunes and geomorphological facies. The samples were analyzed for Granulometry, morphoscopy and mineralogy in the laboratory. Granulometric analysis was performed using dry–sieving technique and the curves and statistics were drawn and calculated using Gradistat software. The morphoscopic and mineralogic investigation were performed using binocular microscope. Granulometric analyses show that the sediments are well sorted, having better sorting than fluvial sediments, with standard deviation of less than 0.5. Morphoscopic analyses mostly show the effect of Aeolian transport on the grains. Mineralogical studies show that the most abundant particles in the sediments are rock fragments consisting of limestone, quartzite and granodiorite (%84), and the rest are minerals such as quartz, feldspat and calcite. About 94.5 percent of the particles have been transported in saltation. The results of differentiation of sediments according to sedimentary processes indicate that about %71.43 of sediments are transported and deposited by Aeolian processes, %21.42 by fluvial processes and %7.15 by overlapping of Aeolian and fluvial processes.
Ghasemali Dianati-Tilaki; Bahman Shakarami; Masoud Tabari; Behzad Behtari
Volume 18, Issue 3 , September 2011, Pages 452-462
Abstract
Salinity is one of the most important abiotic stresses that negatively affects the seed germination and growth of seedlings in plants. NaCl priming is of techniques to improve the seed performance and could increase germination percentage, growth of the seedlings and the mean time of seed germination ...
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Salinity is one of the most important abiotic stresses that negatively affects the seed germination and growth of seedlings in plants. NaCl priming is of techniques to improve the seed performance and could increase germination percentage, growth of the seedlings and the mean time of seed germination under salinity conditions. This study was conducted to improve the seed performance of Festuca ovina under salinity stress conditions. A factorial experiment was applied based upon a completely randomized design with three replications (50 seeds per Petri dish). The effects of priming with three optimized dose (15, 30 and 45 dS/m) of NaCl solution for 24 h at 22±2 oC under dark conditions were assessed for improving seed traits of sheep fescue. NaCl primed Seeds were also examined at different salinity levels) 0, 5, 10, 15 and 20 dS/m). Germination percentage and mean germination time were significantly affected by interaction of salinity and priming. Root length, shoot length and vigor index was not affected significantly by priming treatments in all salinity levels. Germination percentage of primed seeds especially in high salinity levels (15 and 20 dS/m) was greater than to non-primed seeds. The results showed that NaCl priming (especially at 45 dS/m for 24 h) in high salinity levels could increase the seed yield of Festuca ovina in terms of seed germination.
Ali Jahani; Vahid Etemad; Mohammad Doolati; Nazi Avani
Volume 18, Issue 3 , September 2011, Pages 463-473
Abstract
Production of native and non native species in the nursurey is considered as one of the raw materials for reforestation in arid regions. Two important factors affecting the seedling production in the nursery are seed density and seed planting depth which extensive studies have been done in this area. ...
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Production of native and non native species in the nursurey is considered as one of the raw materials for reforestation in arid regions. Two important factors affecting the seedling production in the nursery are seed density and seed planting depth which extensive studies have been done in this area. Therefore in this research the effect of seed density and planting depth on height, diameter growth and viability of H. persicum have been investigated. Haloxylon plantations of Hossein Abad in Qom province with an area of 3180 hectares, is located 30 km south-east of Qom city. Planting depth in four levels of 1, 2, 3 and 4 cm and seed density in five levels of 100, 200, 300, 400 and 500 seeds per 1000 m2were measured. All data were analyzed and the results showed that planting depth of 1 cm had the best results with regard to the basal diameter, height growth and viability percentage so is recommended for reforestration. Planting density of 200 seeds per 1000 m2was also identified suitable for afforestation.
Sadegheh Zarekia; Ali Ehsani; Nilufar Zare; Taghi Mirhaji
Volume 18, Issue 3 , September 2011, Pages 474-485
Abstract
Information on phenology of the range species is important to manage the plans of plant utilization, control of the livestock entry and exit, seed collection, and understanding of the nutritive value of plant species in different phenology stages. In this study, phenology of three important rangeland ...
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Information on phenology of the range species is important to manage the plans of plant utilization, control of the livestock entry and exit, seed collection, and understanding of the nutritive value of plant species in different phenology stages. In this study, phenology of three important rangeland species namely Astragalus chaborasicus, Poa sinaica and Stipa hohenackeriana was studied in Khoshkehrood saveh region. Vegetative and reproductive data of the mentioned species were recorded once a week for two years (2007 and 2008). Growing Degree Days (GDD) were determined using climate data (temperature and precipitation) collected from the nearest station to Saveh. The results showed that start and end of the phonological stages differed in two different years while GDD was almost same for phonological stages. In other words, phenological stages have constant temperature requirement which after obtaining the required temperature the emergence of the stages are observed and thus GDD is applied for prediction of phenological stages.
Mir samad Mousavi; Khadejeh Mahdavi; Ahmad Ahmadi
Volume 18, Issue 3 , September 2011, Pages 486-497
Abstract
Preservation, regeneration, development and management of renewable natural resources (especially vegetation cover) need precise and comprehensive knowledge. In this research, autecology of Caragana grandiflora sp. was studied in Poldasht, West Azarbayjan province. This species is a perennial plant from ...
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Preservation, regeneration, development and management of renewable natural resources (especially vegetation cover) need precise and comprehensive knowledge. In this research, autecology of Caragana grandiflora sp. was studied in Poldasht, West Azarbayjan province. This species is a perennial plant from Fabaceae family. To study the autecology of this perennial plant species, the habitat was determined by field observations and available reports and then climatic and edaphic characteristics of the habitat, plant root system, phenology, reproduction and food compounds were analyzed. The results showed that the habitat of this species was very limited and scattered throughout the North West of the study area. Mean annual precipitation of the habitat was 312.6 mm and mean annual temperature was 12.8 ċ. This species grows in calcic soils with a sandy texture and a PH of 7.5 to 7.67 and an EC of 7.05 to 1.22 ds m-1. The roots of this species is straight, branched and rhizomic that penetrates up to 1.2 m into soil and spreads out up to 3.2 m when encounters a hard and impervious layer. Study of this plant showed that its canopy cover was from 18.63% to 31.12%. Phenological phenomena begin when it sprouts at late February and continues till middle April in the study area. The flowering period is from May to June. It is full of the fruits from middle June and the seed ripens in July. The Laboratory data was analyzed by SPSS software mean comparison was done by Duncan test. Aboveground organ of the plant contains 21.94, 29.37 and 14.25 crude protein respectively in growth, flowering and seeding periods. This species is recommended for range improvement and reclamation in rangelands which have similar ecological condition to West Azarbayjan.
Maryam Dadgar; Masoud Aliha; Enseyeh Faramarzi
Volume 18, Issue 3 , September 2011, Pages 498-504
Abstract
Phosphorus is of macro elements for plant growth. Phosphorus compounds are almost insoluble and available phosphorous in soil is rapidly decreased. Use of phosphate fertilizers in soil has been always one of the fundamental issues in agriculture and production due to the low efficiency of phosphorus ...
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Phosphorus is of macro elements for plant growth. Phosphorus compounds are almost insoluble and available phosphorous in soil is rapidly decreased. Use of phosphate fertilizers in soil has been always one of the fundamental issues in agriculture and production due to the low efficiency of phosphorus fixation in the soil and its uptake by plants. To study the relationship between available Phosphorus and some soil features, soil sampling was performed from 0-30 cm soil depth for 110 samples in Absard. Some soil physical and chemical characteristics such as percentage of sand, silt, and clay, organic matter, calcium carbonate, soil acidity, and available phosphorus were measured and correlation between phosphorus and above soil characteristics was determined. The results showed that significant correlation (P< 0.01) was found between P and some soil properties. In addition, there was a negative correlation between and soil acidity and percentage of calcium carbonate, but a positive correlation was found between phosphorus and organic matter.