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沙棘对中国亚湿润干旱区的杨树人工林养分分布及生物循环影响(英文) 被引量:6
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作者 刘世荣 《生态学报》 CAS CSCD 北大核心 1999年第4期534-542,共9页
通过将沙棘( Hippophae rham noides L.)与三种杨树品种(小黑杨( Pop ulus ‘ Xiaohei’),昭林 6 号杨( P.‘ Zaolin06’)和欧美杨 64 号,( P. euram erican... 通过将沙棘( Hippophae rham noides L.)与三种杨树品种(小黑杨( Pop ulus ‘ Xiaohei’),昭林 6 号杨( P.‘ Zaolin06’)和欧美杨 64 号,( P. euram ericane cv. ‘ N3016’))的人工林分别按株混和行混两种方式进行混交实验,研究了固氮植物沙棘对亚湿润干旱区的杨树人工林养分分布和循环的影响。连续 3a 的观测研究得到以下结果:沙棘叶片的氮、磷和钾的元素浓度显著地高于杨树叶片,混交林中杨树各器官的养分浓度大于纯林中的杨树,但是养分浓度随元素和杨树品种而异;混交林中的土壤的总氮含量和有效氮含量分别比纯林高 86% ~164% 和 19% ~36% ;混交林中杨树生物量增加不总是与叶片的氮素浓度正相关,但是与氮素年吸收量的增加有关;由于混交林中养分的归还与吸收比率大于纯林,所以杨树混交林中养分的年归还量增加,这意味着杨树与沙棘混交之后有大量的养分进入再循环过程。研究结果表明,沙棘在杨树人工林中作为氮泵起到了维持土壤中稳定的氮素有效性以满足杨树迅速生长的作用。 展开更多
关键词 亚湿润干旱区 沙棘 杨树 人工林 养分分布
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Analysis and improving ways for water condition in winter wheat field of dryland in subhumid areas of the Loess Plateau 被引量:1
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作者 Zhong Zhaozhan, Zhao Jubao Institute of Agrometeorology, Chinese Academy of Agricultural Sciences, Beijing 100081,China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1998年第3期85-94,共10页
Based on the soil moisture data from the locating experiments from 1986—1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water cond... Based on the soil moisture data from the locating experiments from 1986—1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water condition in dryland of dry subhumid area of the Loess Plateau were studied. The results suggested that a low precipitation satisfying ratio of 42.9%—58.8% appears in the growing period of winter wheat, and the yield, to a great extent depended on the water that was stored in deep soil layer in the previous rainy season. The filed trial results showed that tillage in the summer fallow period,straw cover, soil moisture regulation with adequate fertilization, crop rotation and proper cropping system could be the efficient ways for improving the water condition,and for the exploitation and utilization of natural water resources(both precipitation and soil water) in the winter wheat field of dryland. 展开更多
关键词 soil moisture water balance precipitation meet ratio dry subhumid area dryLAND rainfed agriculture.
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