Vegetation and soil biota response to experimentally-changed nitrogen inputs in coniferous forest ecosystems of the NITREX project.

A.W. Boxman, K. Blanck, T.-E. Brandrud, B.A. Emmett, P. Gundersen, R.F. Hogervorst, O.J. Kjonaas, H. Persson, V. Timmerman

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Enhancement of the atmospheric N deposition is a serious threat for the structure and function of ecosystems. Here we evaluate the ecological effects of excess N with respect to changes in vegetation and soil biota in a series of experiments along a N gradient across Europe. The aim of this project (NITREX: N saturation EXperiments) is to assess the risk of N saturation and the reversibility of N saturation. At the experimental sites with a low-to-moderate input. N was added (n = 3), while at sites with a high input, N was removed by means of a transparent roof (n = 4). The experiments started between 1989 and 1991. Across the N gradient a positive correlation was found between the N concentration in deposition or soil solution with the N concentration in the needles and in general a negative correlation with the base cartons K and Mg. In the N-addition plots there was a tendency towards a decreasing nutrient status of the needles, whereas at one site N-removal led to an improvement. Addition of N hardly affected fine-root biomass production, whereas signs of growth increase were recorded when the input was reduced. Tree growth was accelerated upon input reduction at two of three sites. Manipulation of N input did not alter the decomposition rate, although significant differences between sites were noted. Manipulation of the N input hardly affected the biomass of fungi and bacteria, but a negative relation between the N-addition and part of the soil fauna may be present among sites.
Original languageEnglish
Pages (from-to)65-79
Number of pages15
JournalForest Ecology and Management
Volume101
DOIs
Publication statusPublished - 1998

Fingerprint

Dive into the research topics of 'Vegetation and soil biota response to experimentally-changed nitrogen inputs in coniferous forest ecosystems of the NITREX project.'. Together they form a unique fingerprint.

Cite this