Lolium perenne grasslands may function as a sink for atmospheric carbon dioxide
Model calculations and scenario studies suggest the existence of a considerable positive feedback between temperature and CO{sub 2} levels in the atmosphere. Rising temperatures are supposed to increase decomposition of soil organic C leading to increased production of CO{sub 2} and this extra CO{sub 2} induces a positive feedback by raising the temperature still further. Evidence was found that negative feedback mechanisms also exist; more primary production is allocated to roots as atmospheric CO{sub 2} rises and these roots decompose more slowly than roots grown at ambient CO{sub 2} levels. Experimental data partly obtained with {sup 14}C-techniques were applied in a grassland C model. The model results show that at an atmospheric CO{sub 2} concentration of 700 {micro}L L{sup {minus}1} increased below ground C storage will be more than sufficient to balance the increased decomposition of soil organic C in a ryegrass (Lolium perenne L.) grassland soil. Once a doubling of the present atmospheric CO{sub 2} concentration has been reached, C equivalent to 55% of the annual CO{sub 2} increase above 1 ha ryegrass can be withdrawn from the atmosphere. This indicates that grassland soils represent a significant sink for rising atmospheric CO{sub 2}.
- Research Organization:
- DLO-Research Inst. for Agrobiology and Soil Fertility, Wageningen (NL)
- OSTI ID:
- 20006652
- Journal Information:
- Journal of Environmental Quality, Journal Name: Journal of Environmental Quality Journal Issue: 5 Vol. 28; ISSN JEVQAA; ISSN 0047-2425
- Country of Publication:
- United States
- Language:
- English
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