期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
明清长江三峡地区外来移民与土地利用
1
作者 杨伟兵 种建荣 《重庆社会科学》 2001年第3期58-60,共3页
20世纪90年代长江流域发生的几次大洪水,引发了全社会对长江上游地区水土保持问题的高度重视。纵观长江三峡开发进程,明清两代移民土地利用对森林植被、水文环境作用至大,影响深远。
关键词 长江三峡地区 外来移民 土地利用 明代 清代 旱地垦殖 水田运动 山地运动
下载PDF
Bioturbation Effects of Branchiura sowerbyi (Tubificidae) on the Vertical Transport of Sedimentary Particles in Paddy Field 被引量:2
2
作者 孙刚 房岩 +1 位作者 王平 丛大力 《Agricultural Science & Technology》 CAS 2010年第8期117-119,共3页
[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and ... [Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and mechanism of benthic Annelida in coupling process of benthic-pelagic interface.[Method]Using chemically stable glass beads as tracers,the vertical transport of sedimentary particles in paddy field was analyzed comparatively with and without B.sowerbyi.[Result]After 10 days' bioturbation of B.sowerbyi,41.3% of the glass beads on the surface of sedimentary particles were transferred downward to the maximum depth of 9.4 cm,and the vertical transportation rate of sedimentary particles was 1.370×10-3/(g·cm2·d). 25.8% and 17.3% of glass beads at a depth of 6 cm were transferred upwards and downwards respectively after bioturbation,to the maximum depth of 5.2 and 2.7 cm respectively,and the vertical transportation rates of sedimentary particles were 8.557×10-4 and 5.738×10-4/(g·cm2·d) respectively.[Conclusion]The sedimentary particles on the surface and deep layer of the paddy field were vertically shifted by the physical activities of B.sowerbyi,thus changed the sedimentary environment. 展开更多
关键词 Branchiura sowerbyi Paddy field BIOTURBATION SEDIMENT Vertical transport
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部