耕地粮食生产潜力及人口承载力研究——以长清县为例

以长清县为例 ,利用 GIS技术和遥感数据 ,按照“机制法”原理计算耕地资源粮食生产潜力。重点是因地制宜、科学确定并计算土壤有效系数和社会有效系数 ,从而得到耕地生产潜力和社会生产潜力像元分布数据。在此基础上 ,进行粮食增产潜力计算 ,并预测未来人口数量发展趋势 ,探讨未来的人口承载力问题。结果表明 :该县粮食增产潜力巨大 ,但是粮食问题仍不容乐观。

Study on Cultivated Land Potential Grain Productivity and Population Carrying Capacity in Changqing County

Since relations among population, land and grain have long been in an intense state in China,studies on Cultivated Land Potential Grain Productivity （CLPGP） and Population Carrying Capacity （PCC） are becoming more and more important. Although achievements have been made in this study field, most of the researches were at macro spatial scales of national and regional levels. This article takes Changqing county of Jinan city, as an example. It belongs to a microscopic region with an area of 1209.19km2. CLPGP and PCC were analyzed with GIS and RS. First, five kinds of CLPGP, i.e., Photosynthetic Productivity, Photosynthetic Thermal Productivity, Climatic Productivity, Potential Land Productivity and Potential Social Productivity, were calculated accurately according to the theory of Limiting Factor Converse Modification. The former three kinds of CLPGP were calculated as the average of the whole county due to their obvious spatial homogeneity. Otherwise, because of the tremendous spatial heterogeneity that determined by the diversity and complexity of limiting factors, the latter two kinds of CLPGP were calculated by the basic grid pixel of 30m×30m in size. In detail, exact mathematic models and the availability of large scale （1∶50000 or 1∶10000） thematic maps of all kinds of physical factors, topographic maps, land use maps, high resolution Landsat TM data and high quality statistical data have ensured the accuracy of the outputs. The results （average value） were: 7681.4 kg/mu （15mu equals 1ha）, 4524.6 kg/mu, 2083.1kg/mu, 1240.3 kg/mu and 713.8kg/mu respectively. Then, based on Potential Social Productivity computation results, database of existing cultivated land and statistical data of grain yield, the Gross Potential Social Productivity and the Potentialyield Increase were calculated respectively. Next, scenarios of grain production in the near future were predicted based on the comprehensive reviews of the history. And the population growth tendency was studied carefully with the mathematic model of GM （1,1）, which has been programmed with BASIC language. As a result, gross population data of 2001²035, a temporal scale that we are interested in, was got. An additional work has to be done was the estimation of per capita consumption capability in the near future. At last, the PCC was discussed. Discussion and conclusions:（1） All the five kinds of CLPGP are very high, and the Potential Land Productivity and the Potential Social Productivity are characterized by their outstanding spatial heterogeneity. But, （2） restricted by physical environment characters and social-economic development levels, such as topographical characters, hydrological characters, precipitation and irrigation conditions, it will be a hard work to improve grain production remarkably in the near future. At the same time, population growth rate is very high and the consumption level of local residents will be dramatically improved continuously. Therefore, （3） problem of foodstuff deficiency may occur in the near future （perhaps before 2035）. This potential foodstuff crisis has already drawn the attention of both government official and scientists. （4） To avoid the potential crisis and ensure the sustainability of socio-economic development, two aspects of effective approach should be reinforced: On the one hand, it is necessary to go on enforcing family planning policy in order to control the stupendous population as well as its striking increase speed. On the other hand, limiting factors nowadays may be facilitative factors tomorrow. So it is necessary to make progress towards the target of improving grain production with new techniques that can weaken or counteract the effects of limiting factors.