北方农牧交错带不同退耕方式对生态健康的影响——以武川县为例

Influence of different ways of returning farmland on ecosystem health in the Northern Agro-grazing Ecotone——A case study of Wuchuan County

以北方农牧交错带武川县为例,针对不同的土地利用方式,对其影响下的生态系统健康状况进行综合评价。选择天然草地、退耕还灌地(柠条地)、退耕还草地(苜蓿地)三类具有代表性的土地类型为研究对象,采用生态系统健康的理论和评价方法,选用生物量、生物多样性指数、土壤含水量和土壤养分含量等指标,从生态系统的活力、组织力和恢复力三方面,对生态系统的健康状况进行了分析比较。结果表明:天然草地具有最高的活力和组织力;两种退耕方式对生态系统活力的影响没有显著差别;退耕还灌较退耕还草地具有较高的物种多样性;退耕还草比退耕还灌消耗更多的土壤水分;两种退耕方式对土壤养分的影响不显著。从水分涵养的角度看,当前退耕还灌较退耕还草好。

Influences of different land use patterns on ecosystem health are analyzed in the Northern Agro-grazing Ecotone. With Wuehuan County as a case study, three types of land were chosen as the sample plots, namely natural grassland, grassland （ Medicago sativa L. ） returned from farmland and shrub land （ Caragana Korshinskii Kom. ） returned from farmland. According to the theory of ecosystem health, the factors which influenced the ecosystem health greatly, vigor, organization and resilience of ecosystem were put forward. The biomass represented vigor, the biodiversity represented organization and the soil water and nutrient represented the resilience. It was showed that the vigor and organization of the natural grassland was the highest of all. There was no obvious difference of effect on vigor under two returning methods; the diversity of the vegetation of shrub land returned from farmland was more than the grassland returned from farmland; water consumption of the grassland returned from farmland was more than the shrub land returned from farmland; two returning methods had no obvious difference of effect on soil nutrient. In terms of conserving water, the shrub land returned from farmland was better than the grassland returned from farmland.