首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Soil nitrogen form and plant nitrogen uptake along a boreal forest productivity gradient
Authors:Annika Nordin  Peter Högberg  Torgny Näsholm
Institution:Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Ume?, Sweden,
Section of Forest Soils, Department of Forest Ecology, Swedish University of Agricultural Sciences, 901 83 Ume?, Sweden,
Abstract:We present results from a study of soil solution concentrations of ammonium (NH4+), nitrate (NO3-), and amino acid N over one growing season along a local 90-m-long plant productivity gradient in a boreal forest. Three forest types are found along the gradient: an ericaceous dwarf-shrub type between 0 and 40 m, a low-herb type between 40 and 80 m, and a tall-herb type at 90 m. Soil sampling of the mor layer was performed in June, July, August and October in the three forest types. In addition, plant uptake of NH4+, NO3- and the amino acid glycine was investigated. A mixture of the three N forms was injected into the soil; one N form at a time was labeled with 15N, and in the case of glycine also with 13C. In the dwarf-shrub forest, where plant productivity was low, the soil N pool was strongly dominated by amino acid N. There, plants took up more NH4+ than NO3-. Glycine uptake did not differ significantly from either NH4+ or NO3- uptake. Along the gradient, soil concentrations of NH4+ and NO3- increased, as did plant productivity. In the low-herb forest NH4+ comprised a major portion of the soil N pool, and plants took up more NH4+ than NO3- or glycine. In the tall-herb forest, NO3- was as abundant as NH4+, and together these two N forms dominated the soil N pool. Here, plants took up nearly equal amounts of NO3- and NH4+, and this uptake exceeded that of glycine severalfold. Apart from the overall preference for NH4+ that plants exhibited throughout the gradient, the results show a correlation between soil concentrations of amino acids and NO3- and plant preferences for these N forms.
Keywords:
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号