【作者】 孙秀锋；

【导师】 刁承泰；

【作者基本信息】 西南大学 ， 自然地理学， 2013， 博士

【摘要】 2012年中国粮食总进口量超过国内粮食总产量的10%,国家粮食安全问题不容乐观。作为一个13亿人口的大国,粮食安全问题关乎国家稳定发展平和社会安定,耕地是粮食生产的基础。习近平总书记在今年(2013年)年中的湖北调研中也强调“粮食安全要靠自己”。保障粮食安全,首先是粮食供求的总量平衡,但我国幅员面积辽阔,区域粮食安全责任分担是国家粮食安全的重要内容,日前的研究多集中于国家宏观层面的粮食安全问题或耕地保护问题,在我国三大粮食区域中,对粮食主产区的粮食生产问题研究亦比较多,从区域粮食安全责任分担的角度对粮食产销平衡区粮食安全与耕地保护研究鲜见。产销平衡区所包括的11个省级行政区中有10个处于我国西部地区,既要保障粮食基本自给,又面临生态环境保护压力及经济发展迫切性。本文以粮食产销平衡区为研究对象,选取具有特征典型性和代表性的重庆市为研究样本,在对我国三大粮食区域的粮食安全特征分析的基础上,通过对粮食产销平衡区粮食安全内涵界定,构建粮食产销平衡区粮食安全模型,并对其粮食安全进行了预测及情景模拟,并进一步从粮食安全视角进行耕地管理分区研究,针对分区结果提出了耕地保护对策,所做工作及研究方法如下(1)中国粮食安全的区域分析。对我国粮食生产的三大区域(主产区、产销平衡区、主销区)的1997-2010年14年间粮食总产量、粮食播种面积以及粮食单产变化特征进行了比较分析,并应用变异系数法对三个区域的粮食单产变化特征进行了刻画,在此基础上从粮食总量及人均粮食的角度进行了粮食安全区域平衡的矛盾分析,明确产销平衡区在国家粮食安全中的地位意义。(2)粮食产销平衡区粮食安全模型构建及验证研究。在对三大粮食区域粮食安全辨识基础上,通过对粮食产销平衡区粮食安全内涵界定,构建粮食产销平衡区粮食安全模型,并以研究样本区(重庆市)为例,对模型进行验证。(3)基于粮食安全模型的粮食安全水平预测。对样本区1997-2010年14年间粮食总产、粮食单产及播种面积变化及波动指数特征进行分析,进而结合人口对研究区粮食安全现状做出判定；分析研究区耕地资源质量、数量变化情况,刻画了粮食安全对耕地数量与质量变化的敏感性；通过自然增长法、回归分析法、横向比较法等途径,对模型中所涉及人口、耕地、人均粮食需求量、粮食单产、复种指数、粮作比等各因子分别预测,测算出目标年(2020年)研究区粮食安全水平,并对不同安全水平下所需耕地资源进行了测算。(4)不同目标管理条件下的粮食安全与政策模型模拟。通过人均粮食需求的纵向变化分析及横向比较参照,确定了研究区四级人均粮食需求目标；分别就不同需求目标、不同粮食安全水平下,从单因子及多因素综合管理角度,对管理决策情形进行了模拟。(5)基于粮食安全视角的耕地管理分区及区域耕地保护策略。从人粮关系的视角,建立了耕地承载力及耕地承载力指数模型,从分区县的尺度对研究区1999-2010年的耕地资源承载力指数时空变化进行分析,利用标准差分级法,对研究区各区县耕地承载力进行分级、分区,分析其时空变化特征及规律。为了更好的反映区域耕地资源保护的外部压力差异及提出具有针对性的耕地保护策略,利用主成分分析法选取社会经济发展指标,测算各区县综合经济发展水平,并利用标准差分级法进行分级；将耕地资源承载力指数分级与社会经济发展水平分级一一对应,制定分级分类规则,将两者的对应情景进行分类、分区；根据分级分区结果,提出耕地资源保护策略。研究结论如下：(1)1997-2010年我国三大粮食产区中主产区粮食产量稳中有升,主销区粮食产量逐年下降,产销平衡区粮食产量波动最大；主产区粮食净剩余量增长缓慢,产销平衡区及主销区粮食净缺口日益增加,粮食总产量区域平衡矛盾越来越突出;产销平衡区的粮食产销基本平衡但缺口有逐步扩大趋势,产销平衡区的粮食安全保障及耕地保护是国家宏观层面粮食安全的重要构成。(2)产销平衡区的粮食安全内涵是指在通过贸易调入或者调出数量相当的粮食品种以平衡粮食生产与消费结构的前提下,地区通过自身的粮食供给基本上能够满足区内的粮食需求,粮食安全水平可以用粮食自给率来反映及表达,其内涵有别于粮食主产区及主销区。其粮食安全模型是一个涉及多因子的动态函数,模型验证显示,人均年消费粮食400kg标准下,2009及2010年样本区粮食自给率分别为86.79%及87.49%,接近可接受的产销平衡区粮食安全水平(自给率90%)；预测模型函数受区域管理政策等多方面影响,可作为区域粮食安全水平及相关政策的检验、评价与预测,工具,避免管理决策的上“黑箱操作”行为。(3)1997-2010年14年间研究样本区(重庆市)粮食播种面积呈逐步下降趋势,期间减少63.8万hm2,但得益于粮食单产的逐年提高,粮食总产基本稳定略有下降,但波动指数呈扩大趋势;由于人口增长重庆市粮食缺口呈扩大趋势,从1999年始由粮食盈余转变为粮食缺口；通过粮食安全敏感性分析,短时间来看,耕地数量及质量变化对粮食产量的影响可能会被水热条件等气候因素变化所掩盖,但从多年耕地变化累积来看,一个区域的气候条件又是相对稳定的,耕地数量与质量才是区域粮食产出的基础性保障。(4)1997-2010年重庆市耕地数量及人均耕地逐年减少,三大区域(一圈两翼)耕地结构差异明显；人均粮食需求随社会经济发展逐步提高,模型预测人均粮食消费全面小康生活水平标准(人均425kg)下2020年重庆市粮食自给率为78.98%,远低于粮食产销平衡要求;以产销平衡区可接受的最低粮食安全水平(自给率90%)测算,耕地缺口31.32万hm2。(5)目标年(2020年)不同粮食消费水平目标下管理政策情景模拟显示,要实现粮食产销平衡难度巨大,由于样本区的典型代表性,这一结果同样能反映整个粮食产销平衡区的情况预期；管理涉及各因子除人口外,其他各因子都落实并依赖于耕地资源这一操作界面上,而人口的从紧管理的各种弊端日益明显,因此耕地资源保护才是确保粮食安全的根本性保障。(6)1999-2010年重庆市耕地资源承载力指数总体呈现出向超载发展趋势,且区域空间差异明显；通过其与经济社会发展水平对应关系研究显示,经济发展水平与耕地资源承载力指数对应关系呈明显的空间分布规律,相同对应类型呈明显的空间聚合性,且与重庆市五大功能区发展格局具有很好的空间吻合性。(7)耕地资源承载力指数与经济社会发展水平对应关系分类与分区能很好的反映区域人粮关系紧张程度与耕地非农占用压力的空间差异,说明该方法具有一定的科学性,能为耕地资源利用保护措施的针对性提供良好基础,这对其他粮食产销平衡区耕地保护分区研究提供了一个可参考的方法和实证案例。(8)粮食产销平衡区其他省级区域具有与研究样本区相似的生态环境压力及经济发展冲动,产销平衡区如对耕地资源利用保护措施不力,粮食净缺量将加速扩大,具有逐步转为粮食调入区的趋势,影响全国粮食安全平衡格局,进而影响国家粮食安全。本文在阐述三大粮食区域特点的基础上,进行了我国粮食安全的区域分析和粮食产销平衡区在国家粮食安全中的定位。以样本区重庆市为例,通过粮食产销平衡区粮食安全模型构建,粮食安全水平预测,目标管理条件下的粮食安全与政策模型模拟以及耕地管理分区及区域耕地保护等方面,对粮食产销平衡区的粮食安全与耕地保护进行较为深入的研究。该研究对于我们认识粮食产销平衡区在国家粮食安全的地位、面临的形势以及为国家和各级政府制定粮食安全与耕地保护相关政策方针提供有益的参考,具有重要的现实意义和一定的理论创新性。更多还原

【Abstract】 In2012, the gross import volume of grain exceeds10%of the gross domestic output in China, which demonstrates that our grain security issue is not optimistic enough. Given that China is a big country with1.3billion people, grain security is related with the stable development of our country and the stability of our society, and cultivated land is the foundation of grain production. General Secretary Xi Jinping also emphasized during his survey in Hubei this year (2013) that"grain security relies on us." Guaranteeing grain security firstly means the gross balance of grain supply and demand. However, China is a vast territory and regional responsibility sharing of grain security is an important content of our grain security. Most of the existing studies are focused on grain security or cultivated land protection in the macroscopic layer. Among the three largest grain areas in China, there are also more studies on grain production of primary production areas, but rarely do studies focus on grain security and cultivated land protection of grain production and marketing balance areas from the angle of regional responsibility sharing of grain security. Among the eleven provincial administrative areas with balanced production and marketing, ten of them are in the west of China, which means they have similar eco-environmental characteristics and bear the same urgency in economic development. Taking grain production and marketing balance areas as the target, this dissertation selects Chongqing Municipality, which is highly typical and representational, as the sample, and constructs a grain security model for production and marketing balance areas by defining the connotation of grain security of these areas on the basis of analyzing the characteristics of grain security of the three grain areas. Also, it forecasts grain security and conducts scenario simulation regarding grain security, further studies subareas for the management of cultivated lands from the perspective of grain security, and puts forward countermeasures of cultivated land protection based on the result of area division. See the work and research methods below:(1) Regional analysis of Chinese grain security. This dissertation conducts a comparative analysis of gross domestic output, grain acreage and variable characteristics of the per unit area yield of grain of our three grain production areas (primary production area, production and marketing balance area, primary marketing area) in fourteen years from1997to2010. Furthermore, it applies variation coefficient method to describe the variable characteristics of the per unit area yield of grain of the three grain production areas, based on which it analyzes the contradictions underlying in the balance of grain security areas from the angle of gross grain and per capita grain, and clarifies the great position and significance of production and marketing balance areas in our grain security.(2) The construction and demonstration study of grain security model for grain production and marketing balance areas. On the foundation of identifying grain security of the three grain areas, this dissertation constructs a grain security model for production and marketing balance areas by defining the connotation of grain security of these areas, and takes the area (Chongqing Municipality) as the example to demonstrate the model.(3) Grain security model-based forecast of grain security level. It analyzes the variability and fluctuation index characteristics of gross domestic output, the per unit area yield of grain and grain acreage of this region in fourteen years from1997to2010, and further determines the current situation of grain security of the region based on its population; analyzes the quality of resources, quantitative characteristics and variances of cultivated lands in this region, and depicts the sensitivity of grain security toward the quantity and quality of cultivated lands; by means of natural increase, regression analysis and horizontal analysis, it forecasts relevant factors respectively, including population, cultivated land, per capita grain demand, the per unit area yield of grain, multiple crop index and the ratio of acreage of grain crops and farm crops, and calculates the grain security level of the region to be studied in the target year (2020) and resources that the cultivated lands might need under different levels of grain security.(4) Grain security and policy model simulation under different conditions of management by objectives. Through the vertical variance analysis and horizontal comparison of per capita grain demand, four levels of per capita grain demand objectives of the region are determined; different management and decision-making conditions are simulated from single-factor and comprehensive multiple-factor management perspective under different demand objectives and grain security levels.(5) Grain security-based management division of cultivated lands and strategies of cultivated land protection. From the perspective of the relations between human beings and grain, the bearing capacity of cultivated lands and the exponential model of the bearing capacity of cultivated lands are constructed, temporal and spatial variance of the bearing capacity index of cultivated lands of the region from1999to2010on the basis of the divided areas and counties is analyzed, and by virtue of standard deviation classification, the bearing capacity of cultivated lands of different areas and counties is graded and divided, and the temporal and spatial variance characteristics and rules are analyzed. With the purpose of better reflecting the external pressure variance of cultivated land protection and putting forward targeted strategies for cultivated land protection, this dissertation selects indexes of social and economic development through principal component analysis and calculates the comprehensive economic development level of different areas and counties, and grades them by standard deviation classification; it also realizes one-to-one correspondence between the index classification of the bearing capacity of cultivated land resources and the classification of social and economic development level, formulates rules of hierarchical classification, and classifies corresponding scenarios of these two; based on the result of classification and area division, this dissertation puts forward strategies of cultivated land protection.See the conclusions of the study below:(1) From1997to2010, the three grain production areas in China have witnessed a steady rise of grain output in primary production area, a decrease year by year in primary marketing area and the most substantial fluctuation of grain output in production and marketing balance area; the net grain surplus in primary production area increases slowly, the net grain mismatch in production and marketing balance area and primary marketing area increases day by day, all of these reflect increasingly prominent contradictions underlying in the regional balance of gross grain output; although grain production and marketing in production and marketing balance area basically maintain a balanced level, the degree of mismatch is gradually expanding. Thus, macroscopically speaking, grain security guarantee and cultivated land protection is an important constitution of grain security in production and marketing balance areas.(2) The connotation of grain security in production and marketing balance area means that the regional demand for grain can be satisfied through the domestic supply on the premise of importing or exporting a certain quantity of grain varieties to balance grain production and consumption structure by trades. The level of grain security can be reflected and expressed by the self-sufficiency rate of grain, and its connotation is different from that of primary production area and primary marketing area. Its grain security model is a dynamic function with multiple factors being involved. It is suggested by model demonstration that under the standard of400kg annual grain consumption per capita, the self-sufficiency rate of grain of the sample area is86.79%and87.49%respectively in2009and2010, which approaches the acceptable grain security level of production and marketing balance area-90%; under the influence of multiple aspects, such as policies of regional management, the forecasting model function can be used as a tool to examine, evaluate and forecast the regional grain security level and relevant policies, and to avoid "backstage operation" behaviors on management decisions.(3) In fourteen years from1997to2010, grain acreage of the sample area (Chongqing Municipality) has witnessed a gradual decrease, during which,638,000hm2has been decreased. However, thanks to the increasing per unit area yield of grain year by year, the gross output maintains at a basically stable level and shows slight drop, the fluctuation index is expanding though; due to the growing population, the grain mismatch of Chongqing Municipality is still expanding, and ever since1999, grain surplus has turned into grain mismatch; in the short term, it can be seen from the sensitivity analysis of grain security that the influence of variances in the quantity and quality of cultivated lands on grain output will probably be covered by changes in climate factors, such as hydrothermal conditions. However, in terms of the accumulated variances of cultivated lands in these years, the climate conditions of an area can be relatively stable, and only the quantity and quality of cultivated lands is the basic guarantee of regional grain output.(4) Chongqing Municipality has witnessed a decrease in the quantity of cultivated lands and the per capita quantity from1997to2010. The three areas (one ring and two wings) present obvious differences in the structure of cultivated lands; per capita grain demand enhances with the social and economic growth, and according to model forecast, the self-sufficiency rate of grain of Chongqing Municipality will be78.98%by the year2020under the standard of overall well-off livelihood in per capita grain consumption (425kg per capita), which is far lower than what it required to realize production and marketing balance; the lowest acceptable level of grain security-90%of production and marketing balance area is used in calculation, and the mismatch of cultivated lands reaches313,200hm2.(5) It is suggested by scenario simulation of management policies under different grain consumption levels in the target year (2020) that it is extremely difficult to realize the balance between grain production and marketing. And since the sample area is highly typical and representational, this result can also reflect the forecast of the whole grain production and marketing balance area; all the other factors involved with management except from population are implemented and depended on the operation interface of cultivated land resources, and various malpractices of strict population management become increasingly obvious. Therefore, only the protection of cultivated lands is the fundamental guarantee of grain security.(6) As a whole, the bearing capacity index of cultivated land resources of Chongqing Municipality from1999to2010presents overloaded development with obvious spatial differences among regions; it is shown by the study on its correspondence with the level of social and economic development that such correspondence shows significant spatial distribution patterns and the same corresponding type shows obvious spatial convergence, which also shows highly spatial conformity with the "one ring two wings" economic development patterns of Chongqing Municipality.(7) The classification and area division of the correspondence between the bearing capacity index of cultivated land resources and the level of social and economic development can well reflect the tension of human-grain relations and the spatial differences of cultivated lands being non-agriculturally occupied, which means this method is scientific to a certain degree and can lay a favorable foundation for the pertinence of measures of protecting cultivated land resource. This provides a referable method and empirical example for the study of cultivated land protection in other grain production and marketing balance areas.(8) Other provincial regions of grain production and marketing balance areas show similar eco-environmental pressure and economic development impulse with the sample area. Provided ineffective utilization and protection of cultivated land resources in production and marketing balance areas, the net mismatch of grain will expand at a high speed and will gradually convert into grain import areas, which will influence the balanced pattern of national grain security and further affect our national grain security.On the basis of elaborating the characteristics of the three grain areas, this dissertation analyzes our grain security regionally and the positioning of grain production and marketing area in national grain security. By taking Chongqing Municipality as the sample area, it constructs a model of grain security of grain production and marketing balance areas, forecasts the level of grain security and simulates grain security and policy model under objective management conditions, and studies the division and management of cultivated lands and cultivated land protection, so as to conduct a more profound study on grain security and cultivated land protection of grain production and marketing balance area. This study provides helpful references to the understanding of the role production and marketing balance areas play in national grain security and the situation they confront with, as well as the formulation of policies related with grain security and cultivated land protection by our country and governments at all levels. Also, this study is of great significance in practice and shows certain innovativeness in theory.更多还原