STUDY ON STRUCTURE AND FUNCTION OF AGRICULTURAL ECG-ECGNOMIC SYSTEM IN OASIS OF ARID LAND A CASE STUDY OF YULI COUNTY IN XINJIANG

农业本质上是一个生态经济系统。本研究以生态经济学核心理论-生态与经济协调发展为主线，以生态学、生态经济学、系统论和分形理论为理论基础，采用理论研究和实证研究相结合、定性分析和定量分析相结合的研究方法，在分析新疆绿洲生态经济系统和绿洲农业生态经济系统运行态势的基础上，以能流、物流、价值流为手段，从县域和农户两个层次上对研究区农业生态经济系统的结构和功能进行分析研究，揭示系统运行的状态、特点、规律及存在的问题，反映其社会、经济、生态效益，为研究区农业生态经济协调发展提出对策建议。主要结论：1．尉犁县农业是一个传统农业与现代农业相结合、既保留有传统农业精华又具有现代农业特点的生态经济系统。2．县域农业生态经济系统总体发展水平不高，协调性差；生态环境脆弱，结构不合理，从而使整个系统的功能和效益低下。表现为以下几点： （功在结构上表现为：水土资源比例不协调；农作物、草场种群结构单一；产业结构不合理，处于重农轻工的农业型结构格局，大农业结构中棉花比重偏高；投入结构不合理，有机能（肥）投入偏低，化肥施用量过高（农田化肥施用折纯量为423kg·ha-1 已超过了最适施肥量范围172一225 kg·ha-1近一倍）。 （2）农田生态系统是系统初级生产力的主体，但其能量、物质和价值的产出水平及投入产出效率属较低水平。投入，岔体水平低且结构不合理、特别是有机能（肥）投入低是影响其能量、物质产出水平和投入产出效率低的主要原因。由于干旱、水资源紧缺等 自然条件的限制，再加上粗放管理和不合理利用，草原、森林系统的能量产出水平极为低下。畜牧业系统规模小，能量转化率和产出水平较低。 （3）大农业结构配比不当，畜牧业规模偏小，初级生产系统和次级生产系统之间能量关系不协调、能流结构偏差很大，既造成初级生产系统的部分生物能流失和浪费严重，又使初级生产系统缺乏足够的有机肥潺赚从而影响整个农业生态系统的能量转化立和产出率。 （4）农户总体的生产经营结构单调，能量利用和转化链条短；牲畜养殖是唯一的次级生产系统，但规模小、管理粗放，能量转化率低，增效不明显。 （5）基于农户类型分析的生态效益和经济效益之间没有相关关；生态效益高，并不意味着经济也高，反之亦然。的群众观和法制观将有助于促进县域农业生态经济的协调发展。Agriculture is an eco-economic system in essence. Under the background of research of this field, taking harmony development between ecology and economy as main thread, considering correlative theories of ecology, eco-economics, systematic theory and fractal theory as instruction, adopting the combined methods of theory study and case study, qualifying analysis and measuring analysis, and on the base of analyzing the present situations of the eco-economic system and the agricultural eco-economic system of the oasis in Xinjiang, this paper studies the structure and function of agricultural eco-economic system of the case region from two levels of county and peasant household through ways of energy flow, material flow and value flow, revealing its developing situations, features and exiting problems and reflecting its benefits of social, economy and ecology. Lastly the paper also gives some suggestions in order to make.the case region realize sustainable development of agriculture. Through research, main conclusions are as follows: 1. The agriculture of Yuli County is an eco-economic system that not only remains the essences of traditional agriculture, but also has some characteristics of modem one. 2. The general harmony-development level between ecology and economy of agricultural eco-economic system of the county region is not high, and its fragile ecologic environments and irrational structure are main reasons that result in bad function and benefit. This is reflected from the following 5 points: (1) In structure it is showed: the unharmonious proportion of water and land resource, its unitary population structure, irrational industrial composition and too high cotton proportion, irrational input structure with lower organic fertilizer and too high chemical fertilizer. (2) The ecologic system of crop field is principal part of productivity in primary production system, but its output level and rate of output to input in energy, material and value is low, and the lower level of input and its irrational structure, especially the lower organic energy (fertilizer) input are main reasons. The limits of natural conditions such as drought and short water resource combining with unscientific management lend to the low energy output level of the system of grassland and forest The scale of animal husbandry is too small and its energy transform efficiency and output level are also not high. (3) The energy relationships between primary and secondary production system are not in harmony and the energy deviation between them is too large, which not only results in the serious waste of organic energy provided by primary production system, but also brings about the lack situation of organic fertilizer source. This would influence the general efficiency of energy transform and output level. (4) The general production and operation structure of peasant households is simple and the chain of energy utilization and transform is short; livestock raising is its unique sub-system of production, but its energy transform efficiency is low and the effect of value increasing is not apparent. (5) There is no close co-relationship between ecologic and economic benefits of production system of peasant households; high ecologic benefit does not mean high economic one, and so in turn. So the general eco-economic harmony development level of production system of peasant households is also not high. 3. Some countermeasures such as adjusting and optimizing industrial structure, improving the ecologic environments of agriculture, developing eco-agriculture and establishing the concept of eco-economic sustainable development in the masses as well as relative laws and regulations are put forward in the paper, which will be contributed to promoting harmony development between agricultural ecology and economy of the county region