基于农户—生态经济模型的耕地石漠化人文成因研究——以重庆市南川区为例

An application of bio-economic household model to analysis of the cause for karst rock desertification in Southwest China

石漠化已成为威胁人类生存的三大生态灾害之一,对其成功治理有赖于人文成因的解明。西南地区石漠化的人类活动驱动力就是作用于自家承包地之上的农户经济行为。以重庆市南川地区为例采用实地测量和问卷调查相结合的方法采集了自然-人文组合式样品,建立了一个农户-生态经济模型。结果表明人地矛盾并没有想象的那样明显地推动了生态环境的恶化,而是农户对土地的依赖要比对土地的负荷产生的环境影响更大;在土地格局已经固定了的情况下贫困农户更加依赖土地,更会采用可持续的土地利用方式,因而其承包地的石漠化率反而偏低,颠覆了前人认为的贫穷是导致石漠化发生原因的观点;石漠化形成的表层原因是外出务工的离心力造成农户对土地的依赖程度的降低,而更深层次的原因是土地产权制度的不完善造成的土地对农户吸引力的减弱。

Rock desertification has been one of the three ecological disasters threatening human beings. Combating desertification relies on the analysis of human factors. The human driving force to rock desertification is farmers economic behaviors in their contractual household lands. Through connecting field surveys with interviews, the authors collected some combined biological and economic samples from Nanchuan District of Chongqing City and constructed a bio-economic household model. The empirical result shows that human- land conflict does not obviously cause ecological disasters expected by scientists. The farmer＇s dependence on the land has more significant environment effect than the load on the land does. On the condition that the location and size of farmer＇s land is fixed, the poor farmers prefer to adopt the sustainable land use types because they rely more on the land, which results in the lower rate of karst rock desertification in their contractual household lands. This empirical result repudiates the prior viewpoint that poverty causes rock desertification. The cause of rock desertification is that the farmer＇s dependence on the land decreases when these farmers become migrant workers, however, the root cause of rock desertification is that the inappropriate ownership structure of land weakens the appeal of land to farmers.