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The effect of elevated CO 2 concentration and soil pH on the relationship between plant growth and rhizosphere denitrification potential
Author(s) -
Hall J. M.,
Paterson E.,
Killham K.
Publication year - 1998
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.1365-2486.1998.00124.x
Subject(s) - rhizosphere , denitrification , microcosm , population , chemistry , environmental chemistry , agronomy , soil water , nitrogen , biology , ecology , bacteria , organic chemistry , sociology , genetics , demography
The effect of CO 2 concentration on plant growth and the size of the rhizosphere denitrifier population was investigated for ryegrass grown at 3 different soil pH values (pH 4.3, 5.9 and 7.0). Soil microcosms were planted with ryegrass and maintained under constant growth conditions at either ambient (450ppm) or elevated (720ppm) CO 2 concentration. At harvest, the rhizosphere soil was collected and subjected to a potential denitrification assay to provide an estimate of the size of the denitrifier population present. Ryegrass dry matter production varied across the pH range studied and contrary to other studies, elevated CO 2 concentration did not consistently increase growth. Plant growth was reduced by ≈ 35% and 23% at pH 4.3 and pH 5.9, respectively, under elevated CO 2 concentration. At pH 7.0, however, plant growth was increased by ≈ 45% under elevated CO 2 . Potential denitrification rates within the rhizosphere followed a similar pattern to plant growth in the different treatments, suggesting that plant growth and the size of denitrifier population within the rhizosphere are coupled. This study investigates the relationship between plant growth and rhizosphere denitrification potential, thereby providing an estimate of the size of the denitrifier population under increased CO 2 concentration and soil pH.