追施氮肥对尾巨桉叶片主要营养元素浓度及贮量变化的影响  

Effects of topdressing nitrogen fertilization on the concentration and storage of major nutrients in eucalyptus leaves

作　　者：周桦[1] 宇万太[1] 马强[1] 徐永刚[1] 陈进宁 陈桂金 李俊真 张日华 

机构地区：[1]中国科学院沈阳应用生态研究所,沈阳110016 [2]广西南宁市高峰林场,南宁530001

出　　处：《生态学杂志》2010年第8期1488-1492,共5页Chinese Journal of Ecology

基　　金：中国科学院知识创新项目(KZCX2-YW-405);国家"十一五"科技支撑计划项目(2008BADA7B08);教育部重点实验室开放基金资助项目(ERCERR08014)

摘　　要：采用田间定位试验方法,研究了追施氮肥对尾巨桉叶片养分浓度与贮量及内外循环的影响。结果表明:桉树落叶时质量损失26%,此时若以单位质量计算叶片养分浓度往往与实际情况不符,因此应以单位叶面积为基础表征养分浓度;与生长叶相比,桉树凋落叶中灰分和有机质含量分别下降33%和25%,表明一些可水解运输的有机物质在叶片凋落前已回输至树体;桉树叶片对N的利用率高达44%,表明存在氮的奢侈吸收。桉树叶片中N、P、K养分以内循环模式为主,内循环比例均在70%以上;Ca则以外循环为主,外循环比例约为90%;Mg、Si和灰分的内循环能力相当,外循环比例略高于内循环。A field experiment was conducted to investigate the effects of topdressing nitrogen on the concentrations and storage of major nutrients and their internal and external fluxes in Eucalyptus urophylla × E. grandis leaves. The mass loss of the fallen leaves was 26%, and thus, to characterize the nutrients concentration by per unit mass was not correspondent with reality, while the nutrients concentration per unit area was a correct characterization. Comparing with those in living leaves, the ash and organic matter contents in fallen leaves decreased by 33% and 25%, respectively, suggesting that some hydrolyzable organic matter was transferred back to the trees before leaf fallen. The nitrogen use efficiency of eucalyptus leaves was up to 44%, showing the luxury absorption of N. The trunk and branch recovered more than 70% of N, P, and K in fallen leaves, indicating that the three elements were mainly cycled in internal flux. Calcium was mainly in external flux, with the scale being about 90%. The internal fluxes of Mg, Si, and ash were almost the same, and their external flux scale was slightly higher than their internal flux scale.

关 键 词：桉树叶片 单位面积 追施氮肥 内循环 外循环 

分 类 号：S792.39[农业科学—林木遗传育种]