Changes in soil carbon and nitrogen properties and microbial communities in relation to growth of Pinus radiata and Nothofagus fusca trees after 6 years at ambient and elevated atmospheric CO2

• Published in: Global change biology 2006-09, Vol.12 (9), p.1690-1706
• Main Authors: ROSS, DES. J., GRAYSTON, SUSAN J., WHITEHEAD, DAVID
• Format: Article
• Language: English
• Subjects: carbon content; Carbon dioxide; Chemical ecology; CLPP; metabolic quotient; microbial communities; nitrification; Nitrogen; qCO2; Soil sciences; Trees
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/j.1365-2486.2006.01212.x

Increasing atmospheric CO2 concentration can influence the growth and chemical composition of many plant species, and thereby affect soil organic matter pools and nutrient fluxes. Here, we examine the effects of ambient (initially 362 μL L−1) and elevated (654 μL L−1) CO2 in open‐top chambers on the growth after 6 years of two temperate evergreen forest species: an exotic, Pinus radiata D. Don, and a native, Nothofagus fusca (Hook. F.) Oerst. (red beech). We also examine associated effects on selected carbon (C) and nitrogen (N) properties in litter and mineral soil, and on microbial properties in rhizosphere and hyphosphere soil. The soil was a weakly developed sand that had a low initial C concentration of about 1.0 g kg−1 at both 0–100 and 100–300 mm depths; in the N. fusca system, it was initially overlaid with about 50 mm of forest floor litter (predominantly FH material) taken from a Nothofagus forest. A slow‐release fertilizer was added during the early stages of plant growth; subsequent foliage analyses indicated that N was not limiting. After 6 years, stem diameters, foliage N concentrations and C/N ratios of both species were indistinguishable (P>0.10) in the two CO2 treatments. Although total C contents in mineral soil at 0–100 mm depth had increased significantly (P