j. fallahi

Climate change by increasing concentrations of greenhouse gases, particularly carbon dioxide, has led to increase attention to the carbon sequestration through the restoration and protection of vegetation cover. In this regards, ecosystems of arid regions have a special importance. In this study the effects of reconstruction and conservation, on soil carbon sequestration of the region of the International Carbon Sequestration Project in Hussein Abad, South Khorasan province of Iran was investigated by a simulation approach using RothC model. In addition, the effects of climate change (increasing temperature and decreasing rainfall) on soil carbon sequestration potential was studied. In the studied area, replanting was done in 2004 and then soil samples were taken every two months during 2010-2011. After collecting the required input data for RothC model (climate, soil and management input data), the model was evaluated and validated for the study area. Moreover, soil carbon sequestration was studied under climate change condition. The simulation results revealed that the RothC model is applicable in rangelands of dry and warm regions, because it estimated the soil carbon changes over the time with proper accuracy. The amounts of model performance index, R2 and RMSE were 0.98, 98% and 0.01, respectively. Simulation study indicated that soil carbon storage will increase from 2011 to 2050 and will be affected by climate change and protection programs. Based on model estimation the amounts of soil carbon in preotected areas will be higher than non-protected areas. Moreover, in non-climate change scenario the amounts of soil carbon will be higher than climate change scenario in 2050.

Seedless Barberry (Berberis vulgaris) is one of the endemic and valuable shrubs that grow as a garden crop only in Iran. In order to study the effect of different harvesting dates (9 September, 1 October, 22 October and 12 November) on quantitative and qualitative characteristics of seedless Barberry, an experiment was carried out based on Complete Randomized Block Design with 3 replications at the Southern Khorasan province in 2008. Results showed that different harvesting dates had a significant effect on fresh fruit yield with branch, fresh fruit yield without branch, branch fresh weight, dry fruit yield, 100 fresh fruit weight, 100 dry fruit weight, pH, brix, acidity and anthocyanin index. The highest and the lowest fresh and dry fruit yield were obtained at final harvesting date (12 November). Moreover, with delaying in harvesting date the brix, pH and anthocyanin index were increased but acidity was decreased. The result of correlation coefficient showed that there was a positive correlation between pH and soluble solids content in extract. But correlation coefficient between pH and acidity was negative. Furthermore, correlation of anthocyanin with brix and pH was positive and its correlation with acidity was negative. Our results showed that the best harvesting date was 12 November that improved qualitative and quantitative indexes of seedless barberry for the studied region.