behzad behtari; Zeinab Jafarian; Hossenali Alikhani
Abstract
Soil heterotrophic respiration, which is the result of soil organic matter decomposition, is affected by environmental factors, especially temperature. A variety of models have been proposed to understanding the respiration response of the soil to temperature and respiration sensitivity to temperature ...
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Soil heterotrophic respiration, which is the result of soil organic matter decomposition, is affected by environmental factors, especially temperature. A variety of models have been proposed to understanding the respiration response of the soil to temperature and respiration sensitivity to temperature (Q10). The aim of this study was to evaluate the respiration response of soil to temperature variations using incubation technique and to examine variety of models in two different management systems. For this purpose, Intact soil samples were collected from a grazing and grazing exclosure in Fandoghlo Ardebil, incubated for 4 weeks at 10, 20 and 30 ° C temperature. Soil respiration was measured by alkaline adsorption method. Nonlinear regression method and The Levenberg-Marquardt algorithm were used to determine the parameters of models. Both ecosystem showed an exponential increase in Soil heterotrophic respiration with temperature. The rate of respiration in soil of grazing, at all three temperature levels, was higher than grazing exclosure. Most models describing the relationship between soil respiration and temperature showed a good fit to the experimental data, especially in the grazing exclosure. Q10 in the grazing (1.21) was higher than the grazing exclosure (0.97). In general, based on the coefficients of the models and the Q10 analysis, the Arrhenius model can be better than the others of model for expressing the relationship between soil respiration with temperature, as well as good numerical estimation for Q10 of soil.
zohre sepehri; Zeinab Jafarian; Ataolah Kavian; ghodratollah heydari
Abstract
Since fire effects on soil properties, awareness about effects of fire on soil is important for fire management. This study was carried out to investigate effects of fire on hydrological, physical and chemical properties of soil in Charat rangeland of Savadkuh. Sampling was performed in two plant types ...
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Since fire effects on soil properties, awareness about effects of fire on soil is important for fire management. This study was carried out to investigate effects of fire on hydrological, physical and chemical properties of soil in Charat rangeland of Savadkuh. Sampling was performed in two plant types Astragalus gossypinus and Artemisia aucheri, 120 soil samples were gathered. Experimental design was factorial design based on complete randomized design with three repeat. Five prepared treatments for Experiment were control soil, burned soil with burner and burned in oven at 100, 300 and 500 °C. Soil characteristics including the texture, saturation moisture, pH, organic matter, field capacity, wilting point, available water and retention capacity were measured in the laboratory. Results showed that percent of sand and pH increased but percent of saturation moisture, silt and clay decreased as temperature increased. On the whole, fire and heat have decreased soil potential of keeping moisture and infiltration considerably. As physical and chemical properties of soil change, especially hydrological ones, living environment of soil microorganisms and plant roots change as well. Besides, amount of runoff and erosion increases.
Zeinab Jafariyan; Leila Tayefeh Seyyed Alikhani; Reza Tamartash
Abstract
Carbon sequestration potential of three species including Agropyron elengatum, Stipa barbata and Artemisia aucheri was evaluated in parts of a semi-arid rangeland in this study. After determination and selecting key areas as study sites, sampling from vegetation and soil, based on randomized systematic ...
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Carbon sequestration potential of three species including Agropyron elengatum, Stipa barbata and Artemisia aucheri was evaluated in parts of a semi-arid rangeland in this study. After determination and selecting key areas as study sites, sampling from vegetation and soil, based on randomized systematic method, was done and 90 plant and 45 soil samples were taken, respectively. Shooting and rooting organs of the species were separated from each other after transfer to the laboratory and carbon sequestration coefficient of plant organs was determined with combustion method.Then carbon sequestration coefficient of different species, organs and soil under these species were analyzed. The results showed that carbon sequestration rate between studied three species, had significantly statistical difference (p
