| Located in the delta of Yangtze River, climate of Jiangsu is in a transitional zone between subtropical and warm-temperate climate regions. Combined with south and north planting characteristics, south Jiangsu, central Jiangsu region and North Jiangsu region were shaped in obvious contrast. Since 1949, Jiangsu’s agricultural development has spanned quite different periods, from planned economy to marketing economy. Economic development has experienced a progress from overall underdevelopment to regional imbalances with a long time span and diverse spatial differentiation. With the increasing development of economy, agriculture and crop production have dramatic changes accordingly. Relying on GIS spatial analysis system, the dissertation explored the evolution characteristics and driving factors of Jiangsu agricultural crop structures since the People’s Republic of China founded based on large number of statistics concerning with Jiangsu agriculture and crops between 1949-2011, and offered references regarding to agricultural macro-development for Jiangsu and other areas as well as present empirical results for GIS research in the field of agricultural history.1. Lay down a unified standard for statistics collection and establish a database on the basis of GIS agricultural thematic information.In terms of Jiangsu administrative division in 2011, taking prefecture -level city and counties under the jurisdiction as the basic unit, data sets are established based on 13 cities and 75 prefecture-level cities of Jiangsu. Established on the basis of GIS, the number of thematic databases regarding to Jiangsu agricultural planting information are up to 0.2 million.2. Jiangsu agricultural planting structures are divided into different phrases based on agricultural major policies adjustment on macro level and planting diversity index variation on micro level.During the period of 1949-2011, when it refers to agricultural planting structure, grains like rice, wheat were taken as staples while cottons, rapes and soybeans were regarded as complement dairy food. In recent 30 years, food consumption upgrade is a reason for the continually increased cultivated area of vegetables and fruits. Agricultural production basically met human being’s demands on livelihood through macro monetary policies adjusting control and marketing economy guidance in 63 years, but agricultural production generally declined when it is regarded as planting diversity index of agricultural ecological system.3.Self-sufficient agricultural planting structure is gradually featured with regionalization and characteristic with the help of GIS, showing major crops’planting area and spatial distribution of crop yields.GIS spatial distribution maps of rice, wheat, rapes, cotton, and vegetables show the different spatial variation characteristics of various crops during the past 63 years. The self-sufficient agricultural pattern is gradually broken and the planting pattern featured with regionalization and characteristic is gradually formed. Taking rice as an example, GIS spatial distribution maps of rice show that rice planting of Jiangsu has two phases of regional shifts. One is a shift of planting area from south to the whole province; the other is that the development of market economy has led rice planting area towards north. Major crops are gradually developing towards regionalization and characteristic under the macroscopical control of policy and the guidance of marketing economy.4.To display the space gravity center’s development traces of major crops’ sown area and total output of Jiangsu province by GIS and the result shows that North Jiangsu has become the agricultural center of gravity of Jiangsu province.Based on the quantitative calculation of the space gravity center of each time, and according to the precise geographical coordinates, this research displays the development traces of major crops’ sown area and total output by GIS. The major crops include rice, wheat, rapes, cottons and vegetables. Taking rice as an example, during the past 63years, the space gravity center’s development trace of rice sown area is from Yangtze East Road of Sanmao town in Yangzhong city of Zhenjiang to Shisanwei in Jiangdu city of Yangzhou to Laowei to Wuwei to Dengjiazhuang toQianzhuang to Hengqiao to Xiaojiazhuang in Gaoyou city to Zhengjia to Chenxi to Lijiasha to Zhouzhuang in Baoying country to Renzhuang. The space gravity center’s development traces of all crops show the same trend, that is they all migrates northward, and this shows that North Jiangsu has become the agricultural center of gravity of Jiangsu province.5. Discuss the correlation between major crops planting structure of Jiangsu and population, economy, policies, science and technology and study, and environment on the correlation degree between crops-planting and economy by means of correlation measurement.The major factor of boosting crops planting is closely tied to high increase rate of population and economy. Correlation measurements are used on analyzing the total number of grain and oil as well as population, the result of which shows the total number of population, grain and oil are significantly correlated at the level of 0.01. And its correlation coefficents are 0.933 and 0.875.Imbalances or diversity of economic development are main reasons for various crops spatial gravity shifts. The status of agriculture in tertiary is a result of social economic development. Correlation analysis of GDP and rice yields in South Jiangsu, central Jiangsu and North Jiangsu from 1952-2011 shows that GDP of south Jiangsu and rice yields appear in an obvious negative correlation at the level of 0.01 and its coefficient of correlation is-0.506. While GDP in north Jiangsu and central Jiangsu are significantly positive correlated to rice yields and their coefficient of correlations are 0.692 and 0.550.Jiangsu’s agricultural planting structure was significantly influenced due to agricultural policies which shows powerful control and regulation force on different regions. However, this kind of force varies from region to region, which caused higher impacts on North Jiangsu area and lower income area compared with south Jiangsu and higher income area. Besides, lacking of cultivated lands makes the overall agricultural production mainly rely on crop yield per unit area improvement. And environmental factors and scientific and technologic improvements are the major factors explaining crop yields per unit area improvement.Demographic pressure brought about an overall downturn in agricultural ecological system diversity index. Only reduce the total number of population and the requirements of lands can really establish a diverse agricultural planting system.GIS, a spatial analysis tool, provides an alternative option for visible research with large quantity, long time span and reliable statistics.
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