Akbar Ghasemi; Heshmat Hydari; Farhad Fakhri; Davud Azadfar; Musa Sadeghi
Volume 16, Issue 3 , December 2009, , Pages 362-374
Abstract
Plant cover is one of the best index for recognizing and describing the environmental changes in the forest. This paper attempts to determine the effects of different desert soil classes on some distinctive plant vegetative characteristics. For the purpose of sustainable management, application of floodwater ...
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Plant cover is one of the best index for recognizing and describing the environmental changes in the forest. This paper attempts to determine the effects of different desert soil classes on some distinctive plant vegetative characteristics. For the purpose of sustainable management, application of floodwater spreading for irrigation of desert plants will meet increase the essential water supplies for desert plants, which in turn create the optimum conditions for desert plant growth. In order to examine the effects of flood water distribution on physico-chemical properties of soil and finally on vegetative characteristics of desert plants an area of approximately 300 hectares located at Tangestan flood water experimental station, in Bushehr, has been divided into three sections of each 100 hectares. Each section received different amount of flood water as entry (treatments).The process of irrigation have been conducted since 1997(11 years). Each section has been divided into two subdivision of upland and down-land subdivisions. Each subdivision has been divided into three secondary subdivisions (18 secondary subdivisions).In each secondary subdivisions soil samples were collected to study the physico-chemical properties of the soil, meanwhile in each secondary sub sample a Cluster sample of 4 plots were studied for the proposed vegetative characteristic of deserts plants: Prosopis juliflora, Ziziphus spina-christi and Acacia nilotica. The experiment has been conducted in the form of split plot design. The results indicate that the mean stem diameter, height and crown diameter differ significantly in sections; section number one has the best growth conditions. Comparison of subsections indicate that the upland and down-land mean stem diameter and crown diameter differs significantly in that the down-land has a better condition of growth. The comparison of soil physico-chemical properties indicate that there is a significant differences between sections and section one is dominated over the others.
Mohammad Hadirad; Reza Mir hoseini; Mohammad ali Meshkat; Mahdi Soltani
Volume 15, Issue 1 , January 2008, , Pages 51-58
Abstract
Weighting lysimeters are good instruments and direct method to plants water needs (evapotranspiration) in arid zones. This research practiced at Yazd Shahid-Sadooghi Desert Research Station. Ten galvanized iron lysimeters (120 cm. diameter & 170 cm. high) were made and constructed after covering ...
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Weighting lysimeters are good instruments and direct method to plants water needs (evapotranspiration) in arid zones. This research practiced at Yazd Shahid-Sadooghi Desert Research Station. Ten galvanized iron lysimeters (120 cm. diameter & 170 cm. high) were made and constructed after covering with a glass-wool layer to minimize the effect of the environment temperature variation on them. Four hatchways installed at different depths (30, 60, 90 and 120 cm) of lysimeters for root and soil sampling and estimating of soil moisture content by TDR instrument. These containers became full with disturbed local soil (l.s tex.), planted and irrigated respectively at the beginning. Lysimeters weighted by a portable liftract which was linked to a powerful (5000 kg. capacity) and accurate (0.1 % sensitivity degree) balance. Drainage water also collected from outlet tubes below of lysimeters occasionally. Results has shown that this procedure have had a good efficiency because achieving to objectives of this research was available. Saving and analyzing of information by computer and with change of weighting method, would also be probable in the future.
Naser Baghestani Maybodi; Mohammad taghi Zare; Jalal Abdollahi
Volume 13, Issue 4 , February 2007, , Pages 337-346
Abstract
Study over vegetation on grazed and ungrazed rangelands is significant for range managemen, this the effects of 2-decade exclusion on vegetation of steppic rangelands in Nir range research station were studied. Three 7.5-hectare experimental plots were selected inside and outside of the exclosure. Exclosure ...
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Study over vegetation on grazed and ungrazed rangelands is significant for range managemen, this the effects of 2-decade exclusion on vegetation of steppic rangelands in Nir range research station were studied. Three 7.5-hectare experimental plots were selected inside and outside of the exclosure. Exclosure site had not been grazed from 1986 to 2004. The adjacent site was continuously grazed at the same time. Cover estimated on quadrates and forage yield were measured by clipping and weighting method. Data were analyzed by t-test method. Results showed that cover, density and yield of Salsola rigida and Stipa barbata increased significantly inside exclosure (p<0.01), but it was not significantly different in Artemisia sieberi (p>0.05).Cover, density and yield of Scariola orientalis , Launaea acanthodes and Noaea mucronatawere greater in grazed area, but only the yield of first species, density of second species and cover and density of third species were significantly high (p<0.05). Two-decade protection from grazing showed that vegetation trend is very slow in arid rangelands.
Jalal Abdollahi; Hosein Arzani; Naser Baghestani; Mohammad Hasan Rahimian
Volume 13, Issue 3 , February 2006, , Pages 162-171
Abstract
Remote sensing is a method to produce updated information in vast area. Describing the model for utilization and processing satellite data in regard to developing a method for mapping forage production of arid regions were the purpose for this study. For this purpose Landsat ETM+ data used at Nodushan ...
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Remote sensing is a method to produce updated information in vast area. Describing the model for utilization and processing satellite data in regard to developing a method for mapping forage production of arid regions were the purpose for this study. For this purpose Landsat ETM+ data used at Nodushan area in 2002 . The study area covers about 60000 hectares and the annual precipitation is about 140-300 mm. in order to correct the necessary data 50 sites with different vegetation types using 25 quadrant of 1*2 m size and then awareged were used. To study the dependent variable of vegetation relations with independent variables of satellite data, vegetation indices and environmental factors; multiple linear regression analysis were manipulated using SPSS software. Then a suitable model was selected which caried predict the vegetation properties of the study area. Finally, production map was produced using ILWIS software. According to the results, mapping of forage production via remote sensing is possible even when its vegetation cover is less than 25%.