The Effect of Environmental Factors On Soil Organic Carbon Stocks: Protected Areas in Jordan As a Case Study.

In this study, the relationships between soil organic carbon, environmental factors, and soil properties were investigated. The objective was to determine the carbon content in the soil within and outside six important rangeland and natural reserves in Jordan which are managed by the Royal Society for the Conservation of Nature. These are: Shaumari, Dana, Debeen, Ajloun, Mujeb, and Yarmook. Shaumari reserve is a very dry area in the northeastern part of Jordan with sparse vegetation cover. Debeen and Ajloun reserves are mostly forest areas with elevation in the range of 550 -1050 m in the northwestern part of Jordan.. Dana and Mujeb reserves are located in south  Jordan and are very mountainous areas characterized by a high variation in elevation, (100-1500 m) and (450-900 m), respectively. Ten sites within each reserve and five sites outside each reserve were selected for soil sampling.  A total of ninety soil samples were taken from the upper soil layer (0-25 cm ) from all the reserves regions. The collected soil samples were analyzed to measure the relevant soil properties (total organic carbon, iron oxides, calcium carbonate, and clay content). Data were statistically analyzed by analysis of variance (ANOVA) and linear multiple regression using SPSS. The mean values of organic carbon were 2.97%, 2.97%, 1.99%, 1.01%, and 0.38% , and 1.23%for Yarmook, Debeen, Ajloun, Dana, Shaumari, and Mujeb, respectively. Results showed a high correlation between the vegetation cover and soil organic carbon. Correlation between soil organic carbon and clay content was not significant except for Shaumari reserve (p<0.05). The soils of unprotected and protected areas differed considerably in their content of soil organic carbon. The difference was significant at p < 0.05.