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Effect of Nitrogen Application on Grain Filling in Maize with Different Nitrogen Efficiency
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作者 黄彦凯 申丽霞 李婷 《Agricultural Science & Technology》 CAS 2015年第7期1440-1446,共7页
There are significant differences in nitrogen absorption and utilization effi- ciency among different maize varieties. So it is very essential to determine nitrogen efficiencies of different maize varieties. The effec... There are significant differences in nitrogen absorption and utilization effi- ciency among different maize varieties. So it is very essential to determine nitrogen efficiencies of different maize varieties. The effect of nitrogen application on maize growth can be reflected at the grain filling stage. Many scholars have researched the differences in grain filling characteristics among different maize varieties under the same nitrogen application conditions, but there are reare reports on the differ- ences under different nitrogen application conditions. In this study, the grain filling dynamics of maize were observed so as to determine the differences in nitrogen efficiency and to further compare the differences in grain filling characteristics a- mong different maize varieties. The test was carried out with Tunyu 99, Luyu 19 and Xianyu 335 as the materials during May 1st to October 7th, 2013. Under the nitrogen application levels of NO (0 kg/hm2 of pure nitrogen), N1 (140 kg/hm2 of pure nitrogen) and N2 (210 kg/hm2 of pure nitrogen), the filling dynamics of upper- and middle- lower-part grains of spring maize were studied. The results showed that among the three nitrogen application level, the grain fresh weight and dry weight of Tunyu 99 ranked as N2〉NI〉N0; the grain fresh weight and dry weight of Luyu 19 ranked as N1〉N2〉N0; the grain fresh weight and dry weight of Xianyu 335 ranked as (N1, N2)〉N0, and there was no significant difference between N1 and N2. Un- der the nitrogen application level of N1, Luyu 19 showed the best growth; under the nitrogen application level of N2, Tunyu 99 showed the best growth, The growth ad- vantage of Xianyu 335 was unobvious under neither N1 nor N2 nitrogen application levels. The development-promoting effect of nitrogen application was more obvious in upper-part grains than that in middle-lower-part grains. 展开更多
关键词 Nitrogen fertilizer MAIZE Nitrogen efficiency Grain filling Grain develop- ment
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走向21世纪的中国国际旅行卫生保健——中国国境卫生检疫工作改革与国际旅卫生保健发展
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作者 宋明昌 《旅行医学科学》 1997年第3期97-101,共5页
美国《时代》周刊发表文章指出:21世纪,一个名副其实的全球性旅行时代来临。旅游业同石油和汽车一起被称为世界三大经济支柱产业。1996年,中国入境出境人员已达1.1亿人次,国际旅游收入超过100亿美元,国内旅游收入超过1600亿人民币。随... 美国《时代》周刊发表文章指出:21世纪,一个名副其实的全球性旅行时代来临。旅游业同石油和汽车一起被称为世界三大经济支柱产业。1996年,中国入境出境人员已达1.1亿人次,国际旅游收入超过100亿美元,国内旅游收入超过1600亿人民币。随着我国认真贯彻党的"十五大",进一步扩大对外开放,国内外旅游业迅速发展,我国国际旅行卫生保健必将取得蓬勃发展。 展开更多
关键词 China international TRAVEL HEALTH care FRONTIER HEALTH and QUARANTINE REFORM develop- ment
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