基于系统平衡的成都市耕地保有量预测

随着城市化进程的加大，耕地减少不可避免，耕地保有量预测为耕地保护提供依据。尝试以成都市2009年为基期，建立了3种人口预测模型，预测出成都市2015年和2020年人口规模。在综合分析四川省人口、粮食单产、复种指数、粮作比等因素的基础上，运用耕地需求量预测模型，预测出成都市基于粮食安全的耕地保有量水平。预测结果表明，人口的迁移增长已成为成都市人口增长的主要方式，2020年人口数量将达到13 069万人，耕地保有量为323 458 hm2，和2020年耕地面积的预测结果相差33 019 hm2。如果按现在的耕地占有速度，2020年将达不到预测的耕地保有面积。根据分析，应该进一步控制人口增长及加大耕地保护力度，提高粮食单产量。

PREDICTION OF CHENGDU' S FARMLAND RESERVE BASED ON SYSTEM BALANCE

Urbanization leads to a fall in farmland. Prediction of farmland reserve can provide a base for farmland protection. This paper, based on a case study on Chengdu in 2009, establishes three population prediction models to assume the population scale of Chengdu in 2015 and 2020, analyzes Sichuan’s population, grain yield, cropping, and applies the farmland demand prediction model to forecast the Chengdu’s farmland reserve based on its food security. The results show that popular migration has become the main source of rising population, with 13 069 thousand people in 2020, the farmland reserve is 323 458 hm2, with a gap of 33 019 hm2 to the forecasted result. If at the current farmland consuming rate, the farmland reserve will not reach the predicted result, which requires to control the population and to protect the farmland and to increase the crop yield.