【作者】 黄凤兰；

【导师】 李凤民；

【作者基本信息】 兰州大学 ， 生态学， 2008， 博士

【副题名】以甘肃省榆中县中连川乡为例

【摘要】 中连川乡地处黄土高原半干旱地区,地区中沟壑纵横的黄土丘陵与长年干旱、水土流失严重的自然地貌与生态环境特征相应,自然生态系统生产力低下,农业经济社会发展水平低下,是世界上罕见的、连片的最贫困地区之一。上个世纪80年代,该地区普遍推广集雨农业工程项目,使该地区于90年代末基本解决了温饱问题。2001-2005年李嘉诚基金项目实施后,人民生活水平有所改善。目前,可持续发展问题,尤其是耕地资源确保人民群众的粮食安全条件下的可持续利用问题,提到议事日程上来了。本论文研究,以农业生态经济系统这一新概念为基础,建立了一个耕地资源在保障粮食安全条件下可持续利用的时间模型,并利用对农户家庭进行长期跟踪调查的数据和乡镇政府的统计数据,对模型进行比对和验证。保障粮食安全条件下的耕地资源可持续利用时间模型建立的假定前提:一是农业生态经济系统是封闭的系统,二是系统中各影响因子都是不变的;三是系统中人均耕地资源面积刚好等于保障年人均最低粮食安全所需的面积,即人均剩余耕地资源面积为零。本研究将经济社会发展的经济指标:最低粮食安全保障线、人口及人口年增长率、耕地资源年均产量等,放到简单的数学生态模型中(该模型包含了Logistic年增长率不变的种群增长模型),得出耕地资源可持续利用时间的基本模型是:模型中,A是耕地资源面积:P是起始年的人口总量;⊿P是人口年增长率;Ea是模型参数,它是保障人均年最低粮食安全所需的耕地面积,它取决于人均年最低粮食安全保障线和耕地资源年产量。由于模型包含了Logistic年增长率不变的种群增长模型,我将t回归到Logistic模型中,得出耕地资源的最大人口承载力模型:事实上,年人均最低粮食安全保障线随着经济社会的发展而变化,农业生态经济系统各相关因子也在不断地变化,因此,模型自身是一个动态的模型。本研究在基本模型基础上,还建立了开放农业生态经济系统耕地资源可持续利用的时间模型。模型建立后,本研究首先将2005年中连川乡的基本数据,运用于耕地资源可持续利用的时间模型中,并运用两种不同的参数进行比对研究,得出中连川乡耕地资源可持续利用的时间模型只能是以发展中国家年人均最低粮食安全保障线决定的参数模型,这与该乡经济社会发展现实相符合。其次,本研究将中连川村1965-2005年的相关数据运用于模型中,实证检验各不同年份耕地资源利用是否具有可持续性。再次,本研究运用模型进行模拟,说明耕地资源利用政策、人口及人口管理政策和农业科技政策的变化,对耕地资源可持续利用时间的影响。最后,本研究模拟政府在管理目标条件下,为实现特定的耕地资源可持续利用时间的管理目标,要求政府分别在耕地资源利用面积、人口及人口年增长率和农业科技政策及其影响下的耕地年均产量等方面作出相应决策,以及三个方面同时决策时的模拟数据。主要结论是:(1)耕地资源可持续利用时间随着系统相关影响因子的变化而变化,耕地资源可持续利用的时间模型是动态模型。(2)耕地资源可持续利用时间与耕地资源面积、耕地年均产量成正比,与人口、人口年增长率成反比。(3)评价耕地资源利用是否具有可持续性的指标有二个,一是耕地资源可持续利用时间;二是耕地资源最大的人口承载力,二者缺一不可。总之,耕地资源可持续利用的时间模型,建立在农业生态经济系统新概念基础上,它解决了Foster提出的长期以来生态学、数学、经济学和人类社会学研究无共同理论基础的问题,填补了长期以来土地资源利用与管理研究中,只有空间模型没有时间模型的空白。模型可用作地方政府对耕地资源利用与管理、人口及人口管理和农业科技政策等方面的决策工具,它为地方政府提供了可持续发展相关决策的模型分析方法和模拟数据。更多还原

【Abstract】 The loess plateau semi-arid area where Zhonlianchuan valley is becomes the peculiar stretch poorest area of the world. This poverty is due to a long-term drought, serious water and soil loss, natural relief, zoology circumstance character and relevant low level of natural zoology system’s productivity and low level of agro-economic-social development. Since 1980’s, the popularization of rainwater harvesting agro-technology constructed with rainwater harvesting project which help of people with basic living problem in 1990’s. Presently, farmer’s living improve after the project sported by Li Kacheng foundation 2001-2005. For now, the sustainable problem, especially the problem of arable land resource sustainable use for ensure food security should put on agenda.This research makes a model base on a new conception—agro-ecology-economic system, for help to take decision to ensure food security during long time in this agro-ecology-economy system. To build and to test this model, I made investigations in the farms and we used the figures of the government of this country.To build a basic temporal model of arable land resource sustainable use to ensure food security, I consider that the average surplus area is null, the average area just the area needed to ensure food security, and that each part of agro-ecology-economic system doesn’t change. I put economic index which is needed by socioeconomic development: the lowest food security, population and the rate of population growth, the productivity of soil, into simple mathematics-ecology model, which includes the Logistic group growth model. This model is:Where A is the land area, P is population at the beginning,ΔP is the rate of population growth, Ea is the parameter of the model,it is the area to ensure food security based on the lowest food security standard and the productivity of soil.As the model includes growth rate of group’s invariable population growth type, I can put t to Logistic group growth model. The system’s largest population endured model is:P_t=P (1+ΔP)~tIn fact, the lowest food security will change while system economic society develops, every part of agro-ecology-economic system is changing, it is a dynamic system. In this research, I made also the temporal model of arable land resource sustainable use in the open agro-ecology-economics system.What this reasearch done the First, to compare with different index of Ea for ensure that the index with the lowest food security which index of developing countries can suitable for the valley. Second, to test this model I apply it on the figures since 1965 to 2005 and it shows when the arable land was sustainability used. Third, I make a simulation to provide the figures about the policies of arable land resource use, population and agro-technology. This simulation shows how the policies of arable land use, population and agro-technology are effective at the same time to change the time of use. Last, I make a simulation about how the time will be change under the government aiming to especially get the eco-sociality. This simulation gives to the government the figures of the extension of the arable land area, or of decreasing of the rate of population growth, or of increasing the productivity of soil. The fallowing are the main conclusions:(1) The time of arable land resource sustainable use change with any factor of the agro-ecology-economic system. The temporal model of arable land resource sustainable use is dynamic model.(2) The time of arable land resource sustainable use is positive with the arable land area, productivity of soil, while it is objective with the population, the rate of population growth.(3) Indexes of estimate the sustainability of arable land resource use are both the time of arable land sustainable use and the largest population endured of the arable land resource.In a word, the temporal model was build base on the noew conception agro-ecology-economic. It solve the theory problem was poited by Foster what about the ecology-economics. It is also solve the problem about that there are nou commund background for research in ecology, mathmatics, ecoeconomics and human-socialogy. It is the frist temporal model in research about soil resource used. The temporal model can be a determination’s tool for local government for arable land resource sustainable use and management, population and population management decision, also the temporal model can provide the modeling analysis method and the simulate figures for the local government to make sustainability decision.更多还原