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Long‐Term Decomposition of Grass Roots as Affected by Elevated Atmospheric Carbon Dioxide
Author(s) -
Ginkel J. H.,
Gorissen A.,
Veen J. A.
Publication year - 1996
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1996.00472425002500050027x
Subject(s) - lolium perenne , loam , decomposition , growing season , carbon dioxide , chemistry , biomass (ecology) , shoot , agronomy , horticulture , botany , soil water , poaceae , environmental science , biology , soil science , organic chemistry
Carbon input into the soil and decomposition processes under elevated CO 2 are highly relevant for C sequestering in the soil. Plant growth and decomposition of root material under ambient and elevated atmospheric CO 2 . concentrations were monitored in wind tunnels. Grass roots ( Lolium perenne L.) were homogeneously 14 C‐labeled at 350 and 700 −L L −1 CO 2 and at two N levels to obtain roots of different qualities. This root material was mixed with fresh loamy sand and transferred to four wind tunnels to observe its decomposition in bare soil and as affected by plant growth ( L. perenne ) at ambient CO 2 and elevated CO 2 for two growing seasons. After the second growing season, elevated CO 2 had stimulated shoot and root growth by 13 and 92%, respectively. The CO 2 and N concentrations at which the grass roots had been grown affected the decomposition rate. After the first growing season, the overall decomposition of 700 roots was 19% lower than that of 350 roots. The 14 C‐labeled microbial biomass in the soil with 700 roots was higher (44%) compared with 350 roots. After the second growing season, the decomposition of 700 low N roots was 14% lower than that of 350 low N roots, whereas the decomposition of the high N roots was unaffected. The 14 C‐labeled microbial biomass in the soil with 700 roots was still higher (30%) than with 350 roots. The combination of higher root yields at elevated CO 2 combined with a decrease in root decomposition will lead to a longer residence time of C in the soil and probably to a higher C storage.