论文部分内容阅读
粮食是当今世界四大问题之一。粮食的增产历来受到各国的重视。世界人口不断增长,而耕地却随着建设的发展而不断减少,依靠开垦已不能满足粮食增产的需要,提高粮食的单位面积产量乃成为解决粮食问题的必由之路。本世纪60～70年代由于培育出了小麦和水稻的矮杆耐肥的新品种,在世界各国广泛推广栽培,同时大量增施氮肥,使小麦和水稻的产量增加了将近一倍,世界粮食问题大为缓和,这就是“绿色革命”对人类做出的贡献。我国人口众多,虽然计划生育收到了显著的效果,人口增长速度大幅度下降,但因基数大,若干年内还将继续增长。由于国民经济建设不断占用土地,使耕地面积不但难以增加,而且还会减少。因此提高粮食作物的单位面积产量仍是发展农业至关重要的问题。目前在我国的粮食作物中已经培育出不少优良品种,如矮杆、耐肥、抗
Food is one of the four major problems in the world today. The increase in grain output has always been valued by all countries. The world population is growing while the cultivated land is declining with the development of construction. Rely on the fact that reclamation can no longer meet the needs of increasing grain output. Increasing the yield per unit area of grain has become the only way to solve the grain problem. In the 1960s and 1970s, due to the cultivation of new varieties of wheat and rice resistant to dwarfing, it has been extensively popularized and cultivated in various countries in the world. At the same time, a large amount of nitrogen fertilizer is applied, which has almost doubled the output of wheat and rice. The world food issue Greatly ease, this is the “green revolution” to make contribution to mankind. Although China has a large population, it has achieved remarkable results in family planning and the rate of population growth has dropped drastically. However, due to a large base, it will continue to grow in a number of years. As the national economy continues to occupy land, the area of cultivated land will not only increase but will also decrease. Therefore, increasing the yield per unit area of food crops remains a crucial issue in the development of agriculture. At present, many fine varieties have been cultivated in China’s grain crops, such as dwarf bars, resistance to fat, resistance