Elevated CO₂ affects the content of glomalin related soil protein in xeric temperate loess and temperate semi-desert sand grasslands.

摘要

Monoliths of temperate loess grassland and temperate semi-desert sand grassland from Hungary were exposed to elevated CO₂ (700 micro mol-1) and present ambient CO₂ concentration in a 6-year open top chamber (OTC) experiment. In loess grassland elevated CO₂ increased both biomass and vegetation cover, whereas there was no similar effect found in semi-desert grassland. The content of glomalin related soil protein (GRSP) increased in both loess and sand grasslands under CO₂ enrichment (early summer aspect). The increase was higher in the case of easily extractable fraction (EEG), representing 14.7 and 22.2% of the chambered control's EEG, for loess and sand grassland respectively. In the case of total glomalin the increase was much lower 7.9% (loess) and 2.6% (sand). On the basis of differences between elevated and ambient CO₂ treatment we could conclude that elevated CO₂ promoted C-deposition in xeric temperate grassland in early summer. Increases of EEG indicate an efficient partitioning of the recently fixed carbon to the soil.