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Litter quality and decomposition in Danthonia richardsonii swards in response to CO 2 and nitrogen supply over four years of growth
Author(s) -
Lutze Jason L.,
Gifford Roger M.,
Adams Helen N.
Publication year - 2000
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.2000.00277.x
Subject(s) - plant litter , zoology , litter , nitrogen , chemistry , lignin , decomposition , agronomy , botany , nutrient , biology , organic chemistry
Summary Litter quality parameters of Danthonia richardsonii grown under CO 2 concentrations of ≈ 359 & ≈ 719 μL L − 1 at three mineral N supply rates (2.2, 6.7 & 19.8 g m − 2 y − 1 ) were determined. C:N ratio was increased in senesced leaf (enhancement ratios, R e/c , of 1.25–1.67), surface litter (1.34–1.64) and root (1.13–1.30) by CO 2 enrichment. After 3 years of growth, nonstructural carbohydrate concentrations were reduced in senesced leaf lamina (avg. R e/c = 0.84) but not in root in response to CO 2 enrichment. Cellulose concentrations increased slightly in senesced leaf (avg. R e/c = 1.07) but not in root in response to CO 2 enrichment. Lignin and polyphenolic concentrations in senesced leaf and root were not changed by CO 2 enrichment. Decomposition, measured as cumulative respiration in standard conditions in vitro, was reduced in leaf litter grown under CO 2 enrichment. Root decomposition in vitro was lower in the material produced under CO 2 enrichment at the two higher rates of mineral N supply. Significant correlations between decomposition of leaf litter and initial %N, C:N ratio and lignin:N ratio were found. Decomposition in vivo , measured as carbon disappearance from the surface litter was not affected by CO 2 concentration. Arbuscular mycorrhizal infection was not changed by CO 2 enrichment. Microbial carbon was higher under CO 2 enrichment at the two higher rates of mineral N supply. Possible reasons for the lack of effect of changes in litter quality on in‐sward decomposition rates are discussed.