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随着人口的增长,农产品的消耗量也必然增加。虽然现有农作物种植面积仅占陆地面积的10％,但继续扩大世界耕地面积的可能性有限。在过去20年中(1957-1977),世界人口从28亿增加到40亿,而耕地面积仅增加了1.35亿公顷(约相当于如今总面积(15亿公顷)的9％。据联合国估计,2000年世界人口将增长到70亿,耕地面积可增加到24亿公顷。从1957-1977年,人均耕地面积已由0.488公顷减少到0.375公顷。预计2000年将减少到0.343公顷,而供粮食生产用的耕地则更少,人均仅0.25公顷。由此可见,人口的增长远远超出了扩大的耕地面积。那么,为了满足人类供养品的需要,必须提高单位面
As the population grows, the consumption of agricultural products will inevitably increase. Although existing crops cover only 10% of the land area, there is a limited possibility of continuing to expand the world’s arable land. Over the past two decades (1957-1977), the world’s population has increased from 2.8 billion to 4 billion, while the area of arable land has only increased by 135 million hectares (about 9% of today’s total area of 1.5 billion hectares.) According to the UN estimates, The world population will increase to 7 billion by 2000 and the area of arable land will increase to 2.4 billion hectares. From 1957 to 1977, the per capita arable land area has been reduced from 0.488 to 0.375 hectares. It is estimated that the area will be reduced to 0.343 hectares in 2000 and will be available for food production Even with arable land of only 0.25 hectares, the increase in population goes far beyond the arable land area, so to meet the needs of human-made supplies, we must increase unit area