Hadi Eskandari Damaneh; Hamid Gholami; Rasool Mahdavi; Asad Khoorani; Junran Li
Abstract
In this study, water use efficiency index (WUE) was used to assessing the effect of drought on the carbon and water cycle. To calculate this index, we used the gross primary product (GPP) and evapotranspiration (ET) products obtained from the MODIS sensor, and the trend of their changes and reaction ...
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In this study, water use efficiency index (WUE) was used to assessing the effect of drought on the carbon and water cycle. To calculate this index, we used the gross primary product (GPP) and evapotranspiration (ET) products obtained from the MODIS sensor, and the trend of their changes and reaction of this index to drought were calculated for the period 2017-2001 in Fars province. Finally, we assessed the land degradation and desertification in different land uses for study area. The results showed that the indices of evapotranspiration, GPP, water use efficiency, and drought increased by 75.25%, 29.9%, 78.51%, and 67.23%, respectively. The effects of drought on evapotranspiration in agricultural lands and grasslands showed more than 67% positive relationship and also, in these land uses, we observed a significant positive relationship (33.4% and 12.5% for the agricultural lands and grassland, respectively). However, in shrubs lands, and savannas, it is more than 66.6% and 87.5%. The effect of drought on water use efficiency in grassland showed that more than 87% of these areas have a positive relationship. The effectiveness of water use efficiency in plants shows a positive relationship in 40.9% in this area, of which only 0.9% has a significant positive relationship. The negative relationship of this land use is about 59.1% of it. Of this negative amount, only 1.6% of the area had a significant negative relationship. The study of this relationship in the use of savannas shows 75% of this area, which includes 1.5 square kilometers.
mahshid souri; mina bayat; Hossein Arzani; Morteza khodagholi
Abstract
Climatic factors are the most important factors affecting vegetation growth and production. The impact of each of these factors in each region varies depending on the vegetation type. The effect of climatic factors (rainfall and temperature) on the production of grazed plant species at 6 steppe sites ...
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Climatic factors are the most important factors affecting vegetation growth and production. The impact of each of these factors in each region varies depending on the vegetation type. The effect of climatic factors (rainfall and temperature) on the production of grazed plant species at 6 steppe sites in Fars province over a ten year period (1998 to 2007) was investigated. 60 plots of 2 square meters along 4 transects of four hundred meters were used to measure cover and production was measured by cutting and weighing method in 15 plots along transects. Then, using regression relationship between canopy cover (percent) and production (kg ha-1), the residual plot yield was calculated for that year. Important climatic indices analyzed in this study are: annual rainfall, growing season rainfall (March to June), plus and earlier rainfall, annual temperature, July temperature, August, maximum and minimum temperatures. The results showed that the average canopy cover was 6.3% and the average yield was 128.5 kg / ha and among the different vegetative forms of shrubs had the highest percentage of cover and production and wheat had the lowest cover and production percentage. Among the important climatic indices, annual rainfall and August temperature at all sites and the growing season rainfall at all sites except for the desired site were the most effective indicators on forage production and showed a positive and significant correlation with forage production.
Gholam Abbas Ghanbarian; Zahra Yazdanpanah
Abstract
َAutecology of Platychaete aucheri Boiss. was studies in south parts of Fars. Climatic data, topography and soil characteristics , vegetation attributes and phenology of desire species were studies. The nutritive value in three major stages was determined. The results showed the plant is able to grow ...
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َAutecology of Platychaete aucheri Boiss. was studies in south parts of Fars. Climatic data, topography and soil characteristics , vegetation attributes and phenology of desire species were studies. The nutritive value in three major stages was determined. The results showed the plant is able to grow under conditions of low rainfall and high temperature , but has little tolerance to cold and frost . The habitat altitude ranges from 543 to 1120 meters above sea level, slope aspect of south and southeast and 7 to 80 percent slope. Average canopy cover of species is between 8.15 to 29 percent. The soils of habitats were neutral to alkaline, non-saline, poor in organic matter and nutrients and the texture is sandy loam. The protein content (%) decreases during phonological stages (at high level 4.53% in flowering stage), also this protein content alone do not satisfy the livestock requirements. Due to the essential oils, the deep root system, woody aerial parts and as well as hairy leaf and stem, grazing pressure can be tolerated. Generally, P.aucheri has several benefits such as adaptation to hot and dry habitats of southern Fars, grazing resistant of life form, attractiveness of beekeeping, uses in traditional medicine and valuable role in controlling water and wind erosion may be introducing and considering as a multiple use species in combat desertification projects and reclamation of winter south rangelands of the country. Knowing of best methods to propagation and successful establishment of this endemic species requires further research.
