ASIAN JOURNAL OF CHEMISTRY, vol.18, no.2, pp.1500-1508, 2006 (SCI-Expanded)
The objective of this study was to determine changes in microbial biomass carbon (C-mic) and organic carbon (C-org) of soil aggregates along a pasture slope. Soil samples from 0-50 mm depth were taken from three landscape positions (shoulder, backslope and footslope) of a pasture in Samsun, Turkey. For each landscape position, soil aggregates were separated into eight aggregate size classes using a dry sieving method and then COT was analyzed. At all positions, macroaggregates (especially 841-1190 and 1190-1680 mu m in sizes) were higher than microaggregates. The contents of C-org varied between 0.65 and 2.08%. The highest C-org contents were found in footslope position and the lowest contents in backslope. All properties are higher at footslope position than the other positions. Generally, C-mic was greater in microaggregates of < 250 mu m, in macroaggregates of 250-420, 420-841, 841-1190 mu m than in the other aggregate size at all positions, whereas C-org : C-mic was higher in macroaggregates of 1190-1680, 1680-2380, 2380-4760 mu m than the other macro and microaggregate size. Consequently, in macroaggregates especially this class is relatively more Cor, than the microaggregates, even if the absolute values of Cmic were lower.