Elham Nouri; Alireza Moshki; Mohammad Matinizadeh; Ali Asghar Zolfaghari; Saeede Rajaei
Volume 27, Issue 4 , December 2020, , Pages 631-671
Abstract
Due to their various roles in the plants’ life, the Arbuscular mycorrhizal fungi (AMF) has been studied from various aspects. In Iran, study on this type of fungi is still at its infancy. Also, the variety of plant species and populations in Iran necessitates a more in-depth analysis compared to ...
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Due to their various roles in the plants’ life, the Arbuscular mycorrhizal fungi (AMF) has been studied from various aspects. In Iran, study on this type of fungi is still at its infancy. Also, the variety of plant species and populations in Iran necessitates a more in-depth analysis compared to other countries in the world. The present study aimed at investigation of the effects of grazing intensity on the diversity and populations of these microorganisms that are symbiotic with the plants and also determining the factors affecting the soil. Three rangelands were considered with three different grazing pressures: no grazing pressure, managed grazing and heavy grazing. Following the sampling of the soil around the rhizosphere of the dominant plant species, the samples were transferred to the laboratory to be analyzed. The results of this study revealed the significant differences in the diversity of AMF species in different sites, and the highest frequency percentage was related to the Septoglomusconstrictum species identified in the heavy grazing region(42.2%).Also, grazing caused changes in the mycorrhizal symbiosis percentage and these factors had a direct correlation, and this could be an evidence of the reduced diversity of AMF, because despite of the existence of spores in the soil, each plant species can only correlate with specific species of AMF. It can be said that appropriate grazing cannot have a negative effect on the population and diversity of AMF, because species diversity indices in a managed grazing region are in a stable state; and, by the proper management of the grazing system and preventing the premature or excessive grazing, its harmful effects can be prevented.
Shole Haj agha Memar; Farshad Keivan Behjou; Kiomars sefidi; Behzad Behtari
Volume 23, Issue 2 , September 2016, , Pages 343-330
Abstract
The aim of this study was to investigate the impact of ecosystem change on emissions and carbon mineralization rate in Fandoghloo region. Soil sampling was performed at three depths (0-30 cm) from the grazing rangeland ecosystem, degraded rangeland ecosystem, and agricultural, ...
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The aim of this study was to investigate the impact of ecosystem change on emissions and carbon mineralization rate in Fandoghloo region. Soil sampling was performed at three depths (0-30 cm) from the grazing rangeland ecosystem, degraded rangeland ecosystem, and agricultural, ecosystem. Carbon dioxide emissions were measured during incubation with alkali absorption method. The highest and lowest emissions of carbon dioxide and carbon mineralization rate were obtained in the grazing rangeland ecosystem (0.968 mg CO2 g-1 soil and 0.00314 mol C kg-1 soil d-1), and the degraded rangeland ecosystem (4693 mg CO2 g-1 soil, and 0.0015mol C kg-1 soil d-1), respectively, showing a significant difference with other ecosystems at different depth levels. According to the results, significant differences were found for the activity of microorganisms in decomposition of organic matter in the study ecosystems. The dynamics of vegetation and returned fine roots caused high emissions of CO2 in soil of grazing rangeland ecosystem. In the agricultural ecosystem, due to the relatively wet conditions and failure to return organic matter to the soil, the decomposition of inaccessible organic matter caused to decreased soil organic matter and low carbon dioxide emissions.