【作者】 王秀丽；

【导师】 张凤荣；

【作者基本信息】 中国农业大学 ， 土地资源管理， 2014， 博士

【摘要】 对农业土地进行合理的利用分区,不仅可以高效利用宝贵的土地资源,而且能够促进生态环境的良性循环、实现经济社会的健康发展。京津地区的地貌类型多样,经济区位差异显著,造成该地区农业土地利用的多样化与复杂化。同时,作为京津大都市区,城市扩张迅速,又面临着严重的水土资源与环境问题。本研究在农业地域分异理论、景观生态学理论、产业结构演进理论、农业区位理论、比较优势理论、可持续发展理论的指导下,借助ArcGIS空间分析、数理统计、景观分析等软件平台,综合分析地貌、经济区位等对京津地区农业土地格局及其变化的影响,并提出了京津地区农业土地利用分区与整治模式。主要研究结果如下：(1)地貌是农业土地利用的基础,决定着农业土地利用的基本方向与布局。本文综合不同地貌区典型土壤样点的点状数据与相关资料的面状数据,通过数理统计与ArcGIS空间分析,从海拔、坡度、土壤、水文状况等地貌要素对作物生长所需的温度、水分、作物扎根立地条件、农业机械化作业条件、灌溉保证率、盐渍化等方面,综合分析了不同地貌区农业用地的立地条件。农业用地自然适宜性评价结果表明：中山区由于海拔高、坡度大、土层薄等限制,不适宜耕作面积比例最大,除林地外,其他农业用地类型较少。低山丘陵区地形和土层限制,为中度适宜,林地、果园面积较大。冲积平原区基本无自然条件限制,土地适宜性最高,适宜多种农业用途,因而农业用地类型多样,而且转换频繁。海积平原区由于受盐渍化影响,整体适宜性次之,农业用地以耕地、其他农用地为主。农业土地利用的分布整体上与大地貌的地域分异规律相符合。(2)以2004年、2012年土地利用现状数据为基础,采用ArcGIS与Fragstats软件研究不同自然适宜区内的农业用地格局变化特征。数量结构变化表明,在城镇化过程中,优质的农业用地资源快速流失,减少面积为766.35km2；灌排等农田基础设施工程的完善和土地整治,提升了原本适宜度级别较低的农业用地等别,使中度适宜区的农业用地呈现增加态势,增加面积为507.60km2低度适宜区农业用地的增加则主要来源于宜耕后备资源的开发,面积增加了329.06km2;比较效益差是农业用地资源流失的根本原因。景观格局变化表明,高度适宜区基本无自然条件限制,产业规模化效益明显,农业用地景观结构变化最频繁；中度适宜区景观结构整体变化幅度较小,具有较强的稳定性,但随着投入增加,农业生产条件改善较大；受自然条件的约束,低度适宜区农业景观格局“地带性”分布明显。研究结果表明,经济社会的发展驱使农业用地呈现以市场需求和经济效益为导向的转换特征。(3)定量评价了大都市不同经济区位下农业用地承受的发展压力大小,并以耕地为对象,进行发展压力差异下的耕地资源时空变化特征研究。结果表明：耕地减少幅度与发展压力之间呈现出高度的空间关联性,即距离中心城区越近,发展压力越大,耕地减少幅度越快；反之,距离中心城区越远,发展压力越小,耕地减少幅度也小。耕地减少的主要因素是农业产业结构调整、建设占用,进一步印证了比较效益差是耕地减少的主要原因。新增耕地的主要来源是发展压力较小地区的农业产业结构调整、未利用地开发；但这些区域大多生态脆弱,并不适宜耕种。因此,协调城市化过程中的农地保护与经济发展之间的矛盾,必须考虑农业土地利用的经济效益。(4)基于都市区农业生产面临的资源与环境问题,在地貌分异的基础上,综合考量区域土地的自然适宜程度高低及经济区位条件,将区域农业用地分为5个区,并提出各用地区的农业主导功能、利用方向与整治模式。(5)美国的土地潜力分类、FAO土地评价基本是依据自然资源禀赋对传统农业的适宜性评价。但是,当社会经济发展到相当高的阶段,技术力量可以克服土地天然的限制性因素,自然条件的限制性对土地利用的影响减弱。因此,土地评价不应再单纯考虑自然适宜性,应该更多地考虑评价区域的经济与社会发展状况,特别是在都市区。但是,有些限制性因素还是比较难以克服的,比如海拔与地形对农业的限制性。本文在自然适宜性评价的基础上,叠加都市经济区位影响大小评价的农业用地分区方法。提出了在两个中心城区之间布置基本农田作为城市增长边界,中心城区周边以农作物作为绿化用地,滨海平原盐碱荒地上发展设施农业的农业用地分区利用建议,为现代农业土地利用分区与布局提供了方法与思路上的借鉴。更多还原

【Abstract】 Reasonable agricultural land zoning not only to realize efficient land use, but also to promote a healthy circulation of ecosystem and stable social development. Urban areas of Beiing-Tianjin region manifest diversified and complicated agricultural land use resulted from evident topographical and economic location differentiation, which also embrace all the conflicts between development and conservation, economy and environment, and urbanization and food security. As a result, researches on the feasibility of zoning in lessening and solving the conflicts in these areas is worthwhile. Based on the theories like regional differentiation, landscape ecology, industrial structure evolution, sustainable development and agricultural location theory and so forth, this article comprehensively analyzed the relationship between topography and agriculture to illustrate the agricultural land use pattern and traits in each topographical area. Furthermore, agricultural land zoning was conducted in urban areas of Beiing-Tianjin region to designate the dominant function and utility direction of each zone. Finally, countermeasures and proposals were put forward to the implementation of agricultural land zoning rehabilitation mode selection. And the main conclusions are drawn as follows:(1) Topography determines the basic pattern of agricultural land use. With the help of mathematical statistics and spatial analyst extension of ArcGIS, soil property data from typical soil samples in different topographical areas and relevant polygon data were analyzed to uncover the impacts of altitude, slope, soil, hydrology and so forth, on the conditions needed by plant growth, like temperature, farming system, soil fertility, rooting condition, agricultural mechanization, probability of irrigation and salinization, which further outlined the general stand conditions of each geographical area. The natural suitability assessment results of agricultural land indicate that borders of each natural suitability grade and that of geographical areas manifest generalized overlaying. Higher mountainou areas was constrained by the high altitude, steep slope and shallow soil in cultivation condition, there are limited agricultural land use, in which woodland accounts for the dominant part. Low mountain and hill areas own moderate limitation in relief and soil condition,which are agriculturally medium suitable. Alluvial plains show highest agricultural suitability nearly without any natural constraint. Diversified agricultural activities exist in these areas and convert into each other frequently. The salinization in coastal alluvial plain areas abates the suitability, in which farmland and other agricultural land make up the most part. The agricultural land use pattern recognizes the similar distribution trend as topography differentiation.(2) Based on the land use data status quo in2004and2012, traits of agricultural land use changes in different area with different natural suitable level were discussed on the support of ArcGIS and Fragstats software. It can be clearly seen that during the progress of urbanization, high quality farmland reduced sharply by766.35km. However, the enhancement of irrigation and drainage infrastructures promote the increase of medium suitable agricultural land. The amount of medium suitable land was increased by507.60km2from2004to2012. Furthermore, culturable wasteland development added329.06km2more low suitable level agricultural land. Low comparative benefits are the main driving force for the shrinkage and conversion of agricultural lands. From the land use structure, it can be seen that without the natural constraints, high suitable land area manifests highest frequency of agricultural land use conversion. The medium suitable land area shows stable landscape structure; and fewer changes occurred during this period. Low suitable land area indicates marked "belt" characteristics for the limitation of natural conditions. All the analyses set forth above reflect socioeconomic factors also drive agricultural land use presented to the market demand and economic transformation-oriented features.(3) The indicator system of development pressure evaluation was established considering economic location, population and income aspects, under the background of macro-socioeconomy. Further evaluation of development and pressure faced by agricultural land in urban areas was performed. And farmland spatiotemporal changes were discussed. From the results we can see that development and pressure levels reflect donut-shaped distribution. There is positive relationship between the shrinking amount of farmland and development pressure, where the closer to central urban area the bigger development pressure is, and resulting quicker farmland shrinkage, and vice versa. The reasons to the shrinkage of farmland are agricultural structure adjustment and encroachment by urbanization, which recognizes that comparative benefit is the dominant driving force. Newly added farmland is from agricultural adjustment and culturable wasteland development. However, this farmland is of ecological fragility, and culturablly farfetched.(4) Five agricultural zones were divided, taking into account the environmental problems, topography, natural suitability and economic Location conditions. And dominant functions utility direction, rehabilitation modes were put forward accordingly.(5) American land capacity classification and FAO land evaluation are suitable evaluation approaches of traditional agriculture based on natural resource characteristics. However, the improvement of science and technology offset the physical constraints. Land evaluation shall embrace the social and economic conditions around as well, especially in urban areas. Natural condition like altitude and landform is still the basic constraint confronted by modern agriculture.Coupled with the tenet, the partition method of agricultural land based on the natural suitability evaluation and economic location superimposed development pressure assessment, it was suggested that arrang basic farm land between Beijing and Tianjing as urban growth boundary, plant grain crops surrounding the two central cities, and develop the facility agriculture such as greenhouse in the coastal plain saline. This land use layout might be the best choice of developing modern agriculture in metropolitan region.更多还原