Mostafa Jafari
Volume 21, Issue 1 , June 2014, , Pages 139-153
Abstract
Iran faced with climate and environmental changes in past years and it is projected that some climatic changes will occur in the future. Net Primary Production (NPP) is an important index to evaluate production in natural ecosystems including forest, rangeland and desert. Climate change impact will cause ...
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Iran faced with climate and environmental changes in past years and it is projected that some climatic changes will occur in the future. Net Primary Production (NPP) is an important index to evaluate production in natural ecosystems including forest, rangeland and desert. Climate change impact will cause changes in biomass production in natural ecosystems. In this research, the vulnerability of NPP in Iranian forest, rangeland and desert ecosystem has been considered. Results of this consideration presented here in six selected climatic zones in Gilan, Mazandaran, East Azerbyjan, Kermanshah, Khorasan and Systan and Baluchestan provinces. According to the result outcomes, total NPP of forest, rangeland and desert ecosystem in Gilan, East Azerbyjan, and Khorasan provinces, under temperature and precipitation changes, has been increased in the year ended 2039. While, the amount of NPP in Mazandaran, Kermanshah, and Systan and Baluchestan provinces would have been decreased. These changes in Khorasan provinces (including North, South and Razavi) will show highest increase, indicating suitable increase of precipitation and temperature in the region. Quantitative changes in NPP depend on total biomass and changes of precipitation and temperature. As an example, these changes in forest ecosystems of Gilan, and Khorasan provinces, will increase and in Mazandaran, and Kermanshah provinces, will decrease. Also, these changes in range ecosystems of East Azerbyjan, and Khorasan provinces, will increase and in Kermanshah, and Systan and Baluchestan provinces, will decrease. While, changes in desert ecosystems of Khorasan provinces mainly will increase and in Systan and Baluchestan provinces, will decrease.
Ali Ehsani; Hosein Arzani; Mahdi Farahpur; Hassan Ahmadi; Mohammad Jafari; Mortezah Akbarzadeh
Volume 19, Issue 1 , June 2012, , Pages 1-16
Abstract
In this study, potential and actual evapotranspiration were estimated by Penman- Matis using climatic data of Saveh Station, and plant and soil characteristics were estimated by Cropwat 8.0 software. Our results showed that potential evapotranspiration in growing season was 6.16 times greater than the ...
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In this study, potential and actual evapotranspiration were estimated by Penman- Matis using climatic data of Saveh Station, and plant and soil characteristics were estimated by Cropwat 8.0 software. Our results showed that potential evapotranspiration in growing season was 6.16 times greater than the average of actual evapotranspiration. Actual evapotranspiration was 1.18 times greater than the average precipitation of growing season. It means that plant species have used the stored moisture for actual evapotranspiration. According to the estimation of actual evapotranspiration in a ten-year period, a model was provided for forage production as Ya= 74.30+ 2.698 (ETact). Accordingly, average forage production of the studied site was estimated as 257 kg/hec. It could be said that actual evapotranspiration as an index for climate yield is one of the fundamental factors in improving water use efficiency. Application of the mentioned climate index in different estimation models of long term forage production could be considered in order to determine the rangeland grazing capacity and developing rangeland insurance as a replacement for the usual methods of production.
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.