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氮、磷添加对半干旱沙质草地植被养分动态的影响

刘大勇1,2;陈平3;范志平1;于占源1,2   

  1. 1中国科学院沈阳应用生态研究所大青沟沙地生态实验站, 沈阳 110016;2中国科学院研究生院, 北京 100039; 3沈阳市东陵区绿化养护管理一所, 沈阳110015
  • 收稿日期:2005-09-29 修回日期:2006-01-09 出版日期:2006-06-10 发布日期:2006-06-10

Effects of N and P fertilization on nutrient dynamics of semi-arid sandy grassland vegetation

LIU Dayong1,2;CHEN Ping3; FAN Zhiping1; YU Zhanyuan1,2   

  1. 1Daqinggou Ecological Station, Institute of Applied Ecology,Chinese Academy of Sciences, Shenyang 110016, China; 2Graduate University of Chinese Academy of Sciences, Beijing 100039, China;3First Station of Dongling District Greening and Management, Shenyang 110015, China

  • Received:2005-09-29 Revised:2006-01-09 Online:2006-06-10 Published:2006-06-10

摘要: 通过对科尔沁半干旱沙质草地进行田间施肥试验,测定植被组成中黄蒿和白草在生长季内(7~10月)的养分动态变化,并结合N∶P化学计量学的原理和方法,研究了半干旱沙质草地的养分限制状况。结果表明,N、P添加下黄蒿和白草地上部分N、P养分浓度都具有明显的季节动态变化。其中,黄蒿和白草地上部分N浓度随时间呈递减的趋势,且它们随时间的递减规律分别可用线性函数Y=a+bX以及幂函数Y=aXb模拟表示,函数中系数b的绝对值可以反映不同养分状况下植株的生长速率;对P浓度来说,黄蒿和白草地上部分P浓度与时间的关系可以用二次函数Y=aX2+bX+c模拟。比较试验条件下植株体内N、P浓度的变化可知,在科尔沁半干旱沙质草地,N素是黄蒿和白草生长的主要养分限制因子,N肥添加下黄蒿和白草地上部分N浓度以及N∶P都显著的增加;P肥添加促进了白草对N素和P素的吸收,使地上部分N、P浓度增加,而对黄蒿没有显著的影响。

关键词: 物种多样性, 物种丰富度, 生态系统功能, 退化生态系统

Abstract: In many terrestrial ecosystems, nitrogen (N) and phosphorus (P) are the most limiting nutrients. In order to determine the nutrient status in semiarid sandy grassland in Keerqin, this paper examined the nutrient dynamics of Artemisia scoparia and Pennisetum flaccidum in their growth period under different fertilizer additions, and based on the principles and methods of N∶P stoichiometry method, investigated the nutrient limit in the grassland. The results showed that the N and P concentrations of A. scoparia and P. flaccidum aboveground biomass had a significant seasonal dynamics under different fertilizer additions. The N concentration of the two species decreased with time, and its dynamics could be simulated by linear model (Y=a+bX) and power function model (Y=aXb). The coefficient b in the equations could be used to indicate the relative growth rate of the shoot under different nutrientstatus. The relationship of P concentrations of the two species with time could be simulated by quadratic equation (Y=aX2+bX+c). Comparing with the nutrient concentration under different fertilizer additions, N was the main limiting nutrient to most species in semi-arid sandy grassland in Keerqin. N fertilizer addition increased N concentration and N:P ratio of the aboveground biomass. P fertilizer addition had little effects on A. scoparia, but increased the P concentration and N:P ratio of P. flaccidum.

Key words: Species diversity, Species richness, Ecosystem function, Degraded ecosystems