黄土丘陵区坡耕地依存度指数动态分析

Dynamic Analysis of the Dependence Index on Sloping Field in the Loess Hilly Region

坡耕地利用是黄土丘陵区水土流失的直接原因,也是这一地区长期以来为了生存和发展的艰难抉择,退耕政策实施后,当地农户对坡耕地的依赖性是否发生了根本性的变化,是退耕成果是否能够巩固的关键。以固原市上黄生态试区为例,根据该试区＂六五＂时期至＂十一五＂时期调查资料,通过构建坡耕地依存度指数分析方法,对上黄试区不同时期坡耕地依存度指数进行了动态分析,结果表明：坡耕地粮食依存度指数在治理前达到0.8,治理后期为0.51,退耕期坡耕地粮食依存度指数显著降低,＂十一五＂末期,坡耕地粮食依存度指数仅为0.09;坡耕地经济依存度指数在治理期间呈波动态势,其值介于0.26~0.36之间,粮食价格和粮食单产是其波动的主要原因。退耕后,坡耕地经济依存度指数明显下降,＂十五＂时期和＂十一五＂时期,坡耕地经济依存度指数分别仅为0.11和0.09,在这其中,政策贡献率分别达到91.97%和91.96%。上述结论说明,上黄试区坡耕地在整个研究期间,特别是退耕期,由于耕地集约度水平的提高,以及农户农业系统外收益的提升,当地农户对坡耕地的依赖程度也随之大大降低,农户对坡坡耕地的投入是一种越来越不经济的行为,退耕坡耕地复耕的可能性大大降低。

The utilization of sloping land is a direct cause of soil erosion in loess hilly region,also,but for local people,in order to survive,they have no choice.After the project of returning cultivated land,how to consolidate the achievement of ecological construction depends on the dependence of sloping land.Shanghuang experimental area was taken as an example,according to the survey data of experimental area from ‘sixth five-year＇period to‘eleventh five-year＇period,and with the method of constructing the dependence index of sloping land,the dependence index changes of sloping land in different periods was analyzed.The results show that the food dependence index reached 0.8before governance,and the index is 0.51after governance,while the index shows steady decline among the period of returning cultivated land,the food dependence index of sloping land is only 0.09during the period of‘eleven five-year＇.Because of the fluctuating of food price and grain yields,the economic dependence index of sloping land shows fluctuating trend during the period of governance,the values vary from 0.26to 0.36.During the period of returning cultivated land,the economic dependence index of sloping land is 0.11in‘tenth five-year＇period and only 0.09in‘eleven five-year＇period.and among which the contribution rate of policy factor is 91.97%and 91.96%,respectively.According to the conclusion,the dependence to the sloping land for local people gradually reduces throughout the study period.Because of the intensive use of arable land and the promotion of external agricultural system benefits,local farmers depending on slope land is also greatly reduced.Farmers′investment on slope farmland is a less economic behavior,which shows that the possibility of sloping land rehabilitation is unlikely.