各地生产经验证明,改进耕作制度、扩大复种面积是我国农业增产的有效措施。我国土地辽阔,自然条件十分复杂,从北方的寒、温带到南方的热带,从西部的高原到东部沿海平原,不同地区有着不同的耕作制度。按一年中农作物成熟和收获次数来讲,有一年一熟制、两年三熟制、一年两熟制、一年三熟制。如果再按栽培的作物种类来讲,就更繁多了,如东北有小麦、杂粮、豆类、水稻等作物的一熟制,华北有杂粮、小麦的两熟制,南方有棉花一熟制、稻麦两熟制、水稻两熟制以及部分地区的稻、麦、 Local production experience has proven that improving the farming system and expanding the area of ​​replanting are effective measures for increasing agricultural output in China. China has a vast land and complex natural conditions. From the cold and temperate regions in the north to the tropical regions in the south, from the western plateau to the eastern coastal plain, different regions have different farming systems. According to the maturity of crops and the number of harvests in a year, there are one year of cooking, two years of three-cooking, two-year cooking, and three-year-old cooking. If we look at the type of cultivated crops, it will be even more varied. For example, in northeast China, there are crops such as wheat, grains, beans, and rice. In North China, there are miscellaneous grains and wheat, and in the south, there is a cotton crop. Rice-wheat double-cropping system, two-cropping system for rice, and rice and wheat in some areas