Enzymatic activity of air-dried and water-stable aggregates of soils under different land use

Under study were the levels of enzymatic (peroxidase, polyphenoloxidase and catalase) activity in air-dry structural particles 1-2 mm thick and water- stable aggregates extracted from the samples of soddy-podzolic soils (under forest and in crop) and typical chernozems used in long-term field experiments including the resting black fallow since 1964, the barren land after the fallowing since 1998 and annually mowed steppe. Peroxodase and polyphenoloxidase activities display approximately similar level being highly changed from 5 to 22 and 2 to 30 mmol/g respectively, whereas the catalase activity seems to be lower from 2 to 7 mmol/g. In the major cases the fermentative activity in water- stable soil aggregates is higher as compared to air-dry structural particles. The peroxidase activity in water- stable aggregates can be considered as an indicator for displacing equilibrium in processes of the organic matter turnover in soils. In soddy-podzolic soils the polyphenoloxidase activity is concentrated in water- stable aggregates, in chernozems it is evenly distributed between structural particles. As distinct from the ferments of carbon cycle (peroxidase and polyphenoloxidase) the catalase activity doesn’t depend on the soil type and its peculiar use.