Ammar Rafiei Emam; Kazem Alavi panah
Volume 13, Issue 1 , February 2006, Pages 1-9
Abstract
Remote sensing plays a considerable role on detection of natural resources features by its multi spectral means. Three decades works of remote sensing scientists have resulted in presentation of several vegetation indices, for soil how ever there are not many examples. TM spectral ratioing have been ...
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Remote sensing plays a considerable role on detection of natural resources features by its multi spectral means. Three decades works of remote sensing scientists have resulted in presentation of several vegetation indices, for soil how ever there are not many examples. TM spectral ratioing have been employed in this study to overcome problem of detection of soil variation. To reach the point spectral ratioing of TM (18 May 1998) was used. Data used in this study were: a) 3 first principle component, b) spectral ratioing of reflectance bands, c) spectral ratioing of Thermal band and d) original bands of TM. Results show that distinction of different soil in possible by PC3 on the basis of soil moisture variation. So, more researches in various regions for more studies in this subject are advised.
Mohammad ali Meshkat; Mohammad reza Daneshvar; Mohammad reza Ekhtesasi; Kazem Dashtakian
Volume 13, Issue 1 , February 2006, Pages 10-16
Abstract
Desertification is important for our country because it refer to land degradation in arid, semi-arid and arid sub - humid zones due to climatic and human agents. General and continuous study, local and exact investigation,and use of current quantitative models is necessary to better understanding of ...
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Desertification is important for our country because it refer to land degradation in arid, semi-arid and arid sub - humid zones due to climatic and human agents. General and continuous study, local and exact investigation,and use of current quantitative models is necessary to better understanding of land degradation process and desert development. In this research that is based on FAO/UNEP provisional methodology , some of the main desertification processes such as: vegetation destruction, wind erosion, and salinization were studied from two aspects:1) current status and 2) inherent risk. This area covers about 327700 hectars, extends to north of Yazd - Ardakan basin. Then, six maps were drawn for three processes and for two aspects which mentioned above, separately in 1:50000 scale, when the field observations and measurements were carried out. Finally two equal maps were provided by combination of six previous maps . Results of this investigation show that at the present time degrees of vegetation destruction, salinization, and wind erosion are ,, severe to very severe ,, ,,,medium to severe ,,, and,, slight to medium,, respectively . However, degrees of these processes from inherent risk aspect are ,, very severe ,, , ,, medium to severe,,, and,, medium to severe,, respectively. Although the FAO/UNEP methodology is the best model , however it has still some problems, such as: Non quantitative of some criteria; Non sensitivity of some indexes to slight changses ; Non measureable of some criteria; and Non equal the number of indexes in different processes.
Saeid Choopani; Mohammad khosroshahi; Mohammad Gholampoor; khosro Mirakhorlo
Volume 13, Issue 1 , February 2006, Pages 17-26
Abstract
The country of Iran is situated in an arid and semi-arid zone, with an average precipitation of about 250 mm per year. Hormozgan province in southern Iran, is one of the most arid parts of Iran with an average annual rainfall of only 170mm. The study area is located ...
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The country of Iran is situated in an arid and semi-arid zone, with an average precipitation of about 250 mm per year. Hormozgan province in southern Iran, is one of the most arid parts of Iran with an average annual rainfall of only 170mm. The study area is located in the Zagros and Makran geological zones.. In the study area the oldest formations are of Palaeozoic age. Another characteristic of the Zagros zone are diapirs. Diapirs rise up from the deepest part of sedimentary rocks, and after cutting through the upper layers, they may appear at the surface, which seriously affect groundwater quality and land use. Desertification; in Iran has occurred from Neosene and Quaternary. Geological formation have important effect on salinisation and desertification. Thus, the geographical investigation of desert area is very important. This investigation is based on GIS method Applications, geological map (1:250000) and supported by, fieldwork. At the first, prepared and digitizing of geological maps by Ilwis program and was carefully checked and corrected where possible. The next step prepared evaporation formation and Quaternary maps and its overlying. Prepared cross map of Quaternary and Hydrographic network and determination of primary and secondary deserts area. The final step was prepared a cross map of primary and secondary desert area map and checked by fieldwork. To comparison between units of desert area map, can be result, more than 78 percent of study area is situated in the deserts area.
Abalfazl Akbarpour; Mohammad bagher Sharifi; Hadi Memarian Khalilabad
Volume 13, Issue 1 , February 2006, Pages 27-38
Abstract
Land cover information can be used in hydrologic modeling to estimate the value of surface roughness or friction. The objective of this work is comparison of two different methods to provide land cover maps using Landsat images to estimate surface roughness in the manning equation and curve number (CN) ...
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Land cover information can be used in hydrologic modeling to estimate the value of surface roughness or friction. The objective of this work is comparison of two different methods to provide land cover maps using Landsat images to estimate surface roughness in the manning equation and curve number (CN) in SCS method in the Kameh watershed located in the North of Torbat Heydarieh. At the first, Radiometric and Geometric correction performed on ETM+ data. Then with field surveying, The land cover classes were defined and training areas were selected. All of the bands with the exception of band 6 were used in classification. Because of low accuracy of village and road classes, These classes were removed from classification process and for entering these classes in the final map, information from the other layers of GIS system were applied. Results of this work show that in the fuzzy method using 3 layers in classification, The overall accuracy is 75.12% and kappa Index is 0.63. While those of fuzzy method using 2 layers in classification and maximum likelihood method are (73.3%, 0.6) and (72.39%, 0.59) respectively. Therefore the fuzzy method using 3 layers in classification is recommended
Hosein Tavakoli; Amr ali Shahmoradi; Ali asghar Paryab; Abass ali Farhanghi
Volume 13, Issue 1 , February 2006, Pages 39-47
Abstract
A vast area of Iran is covered by sand dunes and shifting sands in wich threat the living of habitants in these regions. Biological control is an approprate method for sand dune fixation. So, it is essential to regonize characteristics of psamophyte plant species and introducing suitable speciecs ...
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A vast area of Iran is covered by sand dunes and shifting sands in wich threat the living of habitants in these regions. Biological control is an approprate method for sand dune fixation. So, it is essential to regonize characteristics of psamophyte plant species and introducing suitable speciecs for sand dunes. For this perpose, the ecological characteristics of Ammodendron persicum including phenology, adaptability, soil condition of habitates, response to cutting and grazing, regeneration strategy and seed germination were studied . Ammodendron persicum is a shrub and psamophyte plant with the age of 10 to 50 years. Phenoligically, the growth started in March, flower in about 7 May and reach to seed maturity by 20 June. The seed shaded after maturity but the duration of plant growth depend to amonnt of annual rainfall. Ammodendron is a drought resistant plant, because it is grow well in an area with an average of 150 mm rainfall per year. Ammodendron regenerates by seed and vegetative propagules. Grazer animals use this plant by end of growing season. In general this plant has approparate ecological characteristies in terms of establishment over sand dune and has perspective for using in other sand dune areas. The later case is under investigation.
Ahmad Ahmadi; Abbas ali Sanadgol
Volume 13, Issue 1 , February 2006, Pages 48-52
Abstract
By considering the plant genetic erosion and plant cover retrogression, the range improvement projects such as pit seeding is essential for increasing the range forage production.The evaluation of Goladam’s rangelands showed that due to heavy and contenious grazing, many palatable species ...
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By considering the plant genetic erosion and plant cover retrogression, the range improvement projects such as pit seeding is essential for increasing the range forage production.The evaluation of Goladam’s rangelands showed that due to heavy and contenious grazing, many palatable species are facing extinction and have been seen with low vigorous and vice versa the unpalatable species had high density and vigorous. In West Azarbaijan province there is about 2321013 animal unit far from rangelands capacity, so applying a treatment that can increse forage production is nesessary. The galehdam station that located in cool semi arid region with 325.8 mm annual rainfall was selected For study the effect of pit- seeding on the range condition and range production .For determining the range condition, range production and range trend, applied the four factors method,clipping method and trend balance method respectively.The study was conducted for 5 years and seeded the Agropyron cristatum, Agropyron desertorum , Agropyron elongatum, Onobrychis sativa و Medicago sativa . The result indicated that the range condition promoted to poor condition from very poor condition, and the forage prodution increased 2 folds. The average plant cover and soil conservation reached to 28 & 86 percent at the end of study and they were significantly difference (p< 0.05).
Ebrahim Rahmani; Ali ashraf Jafari; Mojtabah Torkaman
Volume 13, Issue 1 , February 2006, Pages 53-61
Abstract
In order to determine the best ecotype for pasture establishment in Lorestan province, Iran, 18 ecotypes of crested wheatgrass (Agropyron cristatum L.), were evaluated for yield and quality traits. Two experiments were conducted under optimum and drought stress conditions using complete block design ...
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In order to determine the best ecotype for pasture establishment in Lorestan province, Iran, 18 ecotypes of crested wheatgrass (Agropyron cristatum L.), were evaluated for yield and quality traits. Two experiments were conducted under optimum and drought stress conditions using complete block design with three replications in Brojerd, Iran during 2003-2004. The data were collected and analyzed for yield and quality triats. The results of combined analyses over two environments showed that genotypes 208S, 1727P12, 2087P10, 4056P4, 1727P7 and 619S produced highest forage dry matter yield with average values of 1451 to 1774 kg/h under drought stress conditions. The latter ecotype had a good quality. In normal condition 208P10, 208S, 1227P7, 208P8, 1727P10 produced higher dry matter yield than others. It was concluded that genotypes, 208P8, 1227P7, 208S and 208P10 with average values of 1765 kg/h forage production were the best varities for sowing under both irrigation and non irrigation areas. The genotypes 208P13 had both good quality and forage production under irrigation condition and the genotype 529M had good quality but its forage production was poor.
Abbas ali Sanadgol; Mohammadreza chaichi; Anis Bayani Kalagari
Volume 13, Issue 1 , February 2006, Pages 62-68
Abstract
For introduction of high forage yielding annual medics in Gorgan plain , three introduced species of Medicago scutellata , Medicago truncatula , Medicago littoralis and two native species of Medicago orbicularis and Medicago polymorpha were investigated for three years in Araghi- mahaleh research station ...
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For introduction of high forage yielding annual medics in Gorgan plain , three introduced species of Medicago scutellata , Medicago truncatula , Medicago littoralis and two native species of Medicago orbicularis and Medicago polymorpha were investigated for three years in Araghi- mahaleh research station of Gorgan region. A randomised complete block design with four replications was applied.The results showed that the forage yields of the investigated species differed during years of trial due to climatic flactuations and genetical properties. The cool and moisture sencetive species could produce more forages in rainy and warm winters. The drought and cool tolerant species such as M.littoralis had more stable forage yield in fluctuated rainfall and temperature conditions. generally,M.scutellata yielded 2083 kg/ha ,while M.polymorpha , M. truncatula , M. orbicularis and M. littoralis produced 1487, 1257.2, 1076 and 979 kg/ha forages respectively.