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化肥使用等于东方红农场增加一半耕地资源
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作者 林盛忠 《广西热作科技》 1991年第1期48-48,11,47,共3页
化肥对世界农业生产贡献是巨大的。联合国粮农组织在分析世界粮食增产原因时,认为50%是增施化肥的结果;美国农业经济学家也认为,在美国作物单产增加中,50—60%是增施化肥的结果;美还对化肥增产效果进行估计,反映多使用一吨化肥,相当... 化肥对世界农业生产贡献是巨大的。联合国粮农组织在分析世界粮食增产原因时,认为50%是增施化肥的结果;美国农业经济学家也认为,在美国作物单产增加中,50—60%是增施化肥的结果;美还对化肥增产效果进行估计,反映多使用一吨化肥,相当于扩大了20—40亩耕地。 展开更多
关键词 化肥 耕地资源 东方红农场 效益
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ANALYSIS ON THE DYNAMICS OF SPATIAL DISTRIBUTION PATTERN OF MIXED SPIDER POPULATION IN RICE FIELD 被引量:6
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作者 ZhiWang Zhe-mingYuan +1 位作者 Da-xiangSong Ming-shengZhu 《Entomologia Sinica》 CSCD 2004年第4期257-265,共9页
The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice fi... The results make it clear that there are total 11 families, 29 genera and 43 species of spiders in the rice field of Dong Fang Hong Farm. Among them, there are 8 families, 19 genera and 28 species in the early rice field, and 10 families, 27 genera and 36 species in the late rice field. The spatial distribution pattern of mixed spider populations in rice fields was different during different development stages of rice plant. During the prophase, metaphase and anaphase of early rice plant development, the spatial distribution pattern of mixed spider populations was aggregative, random and aggregative respectively. During the prophase, metaphase and anaphase of late rice plant development, the spatial distribution pattern was uniform, aggregative and uniform respectively. 展开更多
关键词 稻田蜘蛛 空间分布模式 混合种群 动态变化 东方红农场 捕食性昆虫
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