Aggregate Distribution of Organic C, L-Glutaminase Activity and Aggregate Stability as Affected by Slope Position

The location of extracellular enzyme activities in soil aggregates can be influenced by slope position. This study aims to determine the effect of slope position on aggregate distribution of organic C and L-glutaminase activity. The soils were collected from different slope positions (shoulder, backslope, footslope and toeslope) at two pasture ecosystems (Fereydoonshahr and Chelgerd, central Iran). A wet sieving procedure was used to separate soil aggregates and then mean weight diameter (MWD) was calculated. Soil organic C (SOC) and L-glutaminase activity (LGL) were measured in the separated aggregates. Results indicated that slope position influenced aggregates distribution and stability through its effect on soil physico-chemical properties. The LGL activity significantly influenced by slope position which was consistent with the pattern of SOC content (Fereydoonsahr: r=0.7, P