Ali Asghar Naghipour Borj; Sina Nabizadeh; Javad Pourezaie
Volume 26, Issue 3 , September 2019, , Pages 587-598
Abstract
Fire is one of the most important influencing factors on the structure and composition of plant communities, especially in arid and semiarid rangelands. This study was designed to investigate the role of fire on vegetation dynamics in semi-steppe rangelands of Central Zagros. ...
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Fire is one of the most important influencing factors on the structure and composition of plant communities, especially in arid and semiarid rangelands. This study was designed to investigate the role of fire on vegetation dynamics in semi-steppe rangelands of Central Zagros. A stratified random sampling was used to collect the data from six sites with one and five years after the last fire. At each rangeland site, 20 plots with four square area meters, 10 plots in the burned sites and 10 plots in the control sites, were used. The cover percentage of each species was accurately recorded. A one-way analysis of variance and Tukey's test were used to compare each of the variables. The results showed that the fire significantly reduced the vegetation cover and litter, and increased the bare soil surface in the region. The composition of the fire region was close to the control area after a period of five years. The fire caused a decrease in the percentage of shrubs and an increase in the proportion of perennial grasses, annual grasses, and annual forbs in the region. The fire also changed the vegetation composition of rangelands, so that the proportion of hemicryptophytes, therophytes, and geophytes were decreased while chamaephytes increased. Fire also increased the proportion of high and moderate palatable species (class I and II) and reduced the proportion of class III species. Based on the results of this study, it can be concluded that the fire reduces litter and increases the bare soil; consequently, the soil erosion is exacerbated, hence this should be considered in rangeland management. Overall, uncontrolled fires in the semi-arid regions of the country will not lead to the restoration of vegetation cover.
Masoud Borhani; Hosein Arzani; Mehdi Basiri; Mohammad Ali Zare Chahouki; Mehdi Farahpour
Volume 21, Issue 3 , December 2014, , Pages 530-540
Abstract
In order to investigate the effects of range management plans on cover, production, litter, and regeneration of plants in Semirum rangelands, 54 sites including 29 with plan and 25 without plan were selected. The implementation of range management plans resulted in the decrease of stocking rate, affecting ...
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In order to investigate the effects of range management plans on cover, production, litter, and regeneration of plants in Semirum rangelands, 54 sites including 29 with plan and 25 without plan were selected. The implementation of range management plans resulted in the decrease of stocking rate, affecting the improvement of vegetation. According to the obtained results, no significant differences were found for the mean total cover, production and number of seedlings between two managements (P<0.05), while in the sites with plan, the cover, production and number of seedlings of class 1 plants, and cover and production of perennial grasses were significantly more than those of the sites without plan. This result was also true in the case of litter. These variations in plant composition were due to the impact of controlling the intensity and timing of grazing on the competition between palatable and perennial species with invasive and annual ones.
Noor ... Abdi; Hasan Madah arefi; Ghava din Zahedi amiri
Volume 15, Issue 2 , January 2008, , Pages 269-282
Abstract
Atmospheric carbon dioxide concentrations have substantially increased in recent decades. Land management practices, however, offer opportunities to mitigate the rise in atmospheric CO2 concentration through sequestration of this additional carbon via storage in plant biomass and soil organic matter ...
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Atmospheric carbon dioxide concentrations have substantially increased in recent decades. Land management practices, however, offer opportunities to mitigate the rise in atmospheric CO2 concentration through sequestration of this additional carbon via storage in plant biomass and soil organic matter in a process termed terrestrial C sequestration. Rangelands ecosystems have a large potential to sequester C because they occupy about half of the world's land area. In Iran, the Astragalus rangelands with about 17 million hectare area have 10% of the country land area and have the important role in carbon sequestration. In order to investigation the role and potential of Astragalus rangelands in carbon sequestration, a study was carried out at a key area of Astragalus verus-Bromus tomentellus vegetation type in Malmir rangeland site, Shazand township of Markazi province and the content of aboveground and underground biomass carbon, litter carbon and soil organic carbon was determined. The results showed that the total carbon sequestration per hectare was 32.95 ton and 87.43 % of total carbon sequestration was soil organic carbon. The results of biomass carbon distribution showed that the carbon content in aerial biomass was higher than underground biomass. Correlation and stepwise regression analysis revealed that the content of carbon sequestration was positively related to Astragalus height and volume, aerial and underground biomass, total biomass, litter amount and soil organic carbon (SOC) content. It was concluded that the Astragalus rangelands have a large potential to sequester carbon and the soil is most important sink for organic carbon storage in this rangelands