【摘要】 研究了阿拉善荒漠草地过度放牧和围封恢复对地上植被特征及土壤有机碳的影响。结果表明,草地盖度、高度和生物量均为围封6年>围封2年>自由放牧;0～10cm土层中有机碳含量也显示相同趋势,为围封6年(2 17gkg)>围封2年(1 79gkg)>自由放牧(1 72gkg),10～20cm土层土壤有机碳含量随恢复时间略有增加,但无显著差异(p>0 05)。在风蚀较严重的阿拉善荒漠草地,过度放牧对草地植被、土壤养分及其周围环境有极严重的负面影响,采取封育措施后,草地植被恢复、输入土壤的凋落物增加,植被盖度提高使土壤免遭风蚀,促进了土壤有机碳含量增加。更多还原

【Abstract】 The study was carried out within the Alxa desert steppe, Inner Mongolia of north China, Alxa desert steppe is one of serious degraded areas in the semiarid zone of north China. The influences of overgrazing and exclosure on the concentration of organic carbon in soils and the characteristics of vegetation were studied, three adjacent 1-ha research areas of flat dune topography were selected, with exclosure for 6 years (6Ex) and exclosure for 2 years (2EX), and the area had been continuously over grazed (FZ). The result showed that (1)the trend of characteristics of vegetation among the tree research areas were exclosure 6 a >exclosure 2 a>free-grazing. (2)the organic carbon of surface soils (0～10 cm) were similar, exclosure 6 a (2.17 g/kg)> exclosure 3 a (1.79 g/kg)> free-grazing(1.72 g/kg). The organic C of 10～20 cm soils slightly increased with exclosure, but no significant differences. The results suggested that overgrazing in the erosion-prone desert steppe was very detrimental to vegetation, soil and surrounding environment. Under exclosure conditions, vegetation restoration and litter accumulation increase, effectively protected soils from loss through wind erosion. It is concluded that the degraded desert steppe would contribute to significant increase of carbon and the cover of vegetation with the implementation of protecting practices.更多还原