基于动态CGE模型情景模拟的蔬菜价格波动与价格传导机制研究

In recent years, China's vegetable production and demand have undergone major changes. All of farm, wholesale and retail prices have fluctuated sharply and a vertical asymmetric price transmission has been shown significantly. Vegetable price fluctuation has a great impact on farmers' income as well as consumer welfare. We choose six representative vegetables including Chinese cabbage, cabbage, cucumber, tomato, green pepper and eggplant and characterize the recent trends of Chinese vegetable supply, demand and prices. We will collect farm prices in the main production regions, wholesale prices in the wholesale market, and retail prices in farmer's market in regional hub cities. We will develop econometric models including structural equation model and error correction model to investigate the major factors affecting vegetable farm prices, the wholesale prices and retail prices as well as the intrinsic link and price transmission mechanism among the three. A dynamic CGE model will be used to simulate and analyze the effects of the changes of macroeconomic factors, production cost, transportation cost and retail cost on vegetable prices, farmers' income, consumer welfare and average price levels of the society as well as on regulatory effects of policies for different vegetables industry. Lastly, it explores coordination of all parties' interests on the basis of the above, stability of vegetable market prices, and policies and suggestions which promote the healthy development of vegetable industry.

近年来，受市场供求关系等因素影响，我国蔬菜收购、批发和零售价格均出现大幅波动，并呈现出明显的纵向不对称价格传导特征。蔬菜价格波动对菜农收益和消费者福利均产生较大影响。本项目拟从我国蔬菜供求和价格波动的现状、特征及变化趋势出发，选取大白菜、圆白菜、黄瓜、西红柿、青椒和茄子六种代表性蔬菜，采集并依据其主产区收购价、重点批发市场批发价和区域中心城市农贸市场零售价，运用结构方程模型、误差修正模型等计量经济模型，深入研究蔬菜收购价格、批发价格和零售价格波动的原因以及三者之间的内在联系和传导机制；并构建动态CGE模型模拟分析宏观经济因素、生产成本、运输成本、零售成本变动对蔬菜价格、菜农收益、消费者福利和社会总体价格水平的影响、以及不同蔬菜产业政策的调控效果；在此基础上探讨协调各方利益，稳定蔬菜市场价格，促进蔬菜产业健康发展的政策建议。

我国是蔬菜生产与消费大国，蔬菜产业是我国农业和农村经济发展的支柱产业之一。蔬菜生产的季节性特征与蔬菜消费的日常性特点之间的矛盾造成蔬菜价格在频繁大幅波动的同时，还表现出蔬菜“卖菜难”和“买菜贵”并存的现象。极低的蔬菜田间收购价与居高不下的城市蔬菜零售价形成强烈反差。本研究从我国蔬菜供求和价格波动的现状、特征及变化趋势入手，通过构建计量经济模型，分析蔬菜收购价格、批发价格和零售价格的形成、波动与传导机制问题。本研究选取了典型的蔬菜品种，系统收集了蔬菜收购价格、批发价格和零售价格的相关数据资料，并从不同蔬菜品种之间、蔬菜产业链各环节之间以及不同地区之间蔬菜价格的传导方向、传导幅度、传导时滞等方面进行深入分析。.本项目通过研究发现，我国蔬菜价格波动具有明显的季节性和周期性波动特征，长期来看蔬菜价格呈上涨趋势，短期来看蔬菜价格波动的频率和幅度较大；蔬菜收购价格、批发价格和零售价格短期内主要由市场供求状况决定，而长期来看则由整个行业的平均成本决定；我国蔬菜价格传导可以分为不同蔬菜品种之间的价格传导、蔬菜产业链各环节之间的价格传导和不同地区之间蔬菜价格传导三种方式，且蔬菜产业链各环节之间价格传递存在非对称性；批发市场在蔬菜流通和价格波动及传导过程中占据重要地位，蔬菜批发价格对蔬菜收购价格和蔬菜零售价格的形成和波动产生重要影响；通过构建CGE模型进行模拟分析，可以看出蔬菜价格波动对蔬菜生产者、经营者和消费者均存在较大影响，且对城市低收入消费者和蔬菜生产者的影响更加明显。.在此基础上，本研究提出促进我国蔬菜价格稳定和蔬菜产业健康发展的政策建议，一方面必须充分发挥市场机制的作用来调节我国蔬菜的供求和价格，另一方面，加强政府对蔬菜产业的宏观调控，重点加强生产和流通的基础设施建设、提高蔬菜产业信息服务水平和提升蔬菜市场的公益性功能，并在蔬菜价格出现异常波动时采取有效措施进行积极干预。