Abstract: 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 humanland 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.

Key words: rock desertification rate, household economic behavior, bio-economic household model, STIRPAT model, farmland dependence