Abstract:

Food security is the focus in the international community, but focus on the threat of arable land decrease, ignoring the multiple crop index (MCI) change in recent years. The middle and lower reaches of Yangtze River is an important grain production area in China, multiple cropping is an important ways of improving yield over there. That qualitative analysis MCI change for the national grain yield fluctution influence through constructing mathematical model in the middle and lower reaches of Yangtze River, it made a great innovation and breakthrough in theory. Research showed that, the MCI, food and crop planting area drops, grain yields percentage of China, grain sowing area and crops area ratio drops respectively 7.0 and 7.2 percentage points in the middle and lower reaches of Yangtze River during1979-2008, to influence on the national food security. Puts forward improving the level of agricultural mechanization, innovation land system, strengthening grain production of science and technology support system, building and perfecting the grain information early warning system for measures were to solve the problems.