Protease activity of mealy-carbonated chernozems under different types of land use

The protease activity of powdery carbonate chernozems (Haplic Chernozem Hypocalcic) was studied under various types of land use – arable land, virgin land, fallow. The research area is located in the Tugnui basin, Mukhorshibirsky district, Republic of Buryatia. The activity of the protease enzyme was determined by application using photographic film, which was laid in a layer of 0–20 cm of soil. Observations of protease activity in the first year of the study showed that the maximum activity occurred at the end of July–beginning of August. On arable land, the indicator was 35–39%, on fallow land – 34– 36%, on virgin land – 33–39%. In the 2nd year of the study, proteolytic activity increased from the beginning of the growing season. The first peak of activity was observed in the 2nd half of July, which amounted to 44% in arable land, 43% in fallow, and 47% in virgin lands. The second peak of protease activity occurred in the 2nd half of August and amounted to 30% in arable land, 35% in fallow and 37% in virgin lands. In chernozems, proteolytic activity was higher in virgin lands, its intensity decreased from arable land to fallow lands. This indicated an average proteolytic activity in powdery carbonate chernozems under various types of land use. Focality and mosaic character were noted during gelatin hydrolysis as a result of 10-day exposure in all variants. This indicated an uneven distribution of enzyme systems in the soil column and the presence of separate microzones with different protease activity. Statistical processing of the data showed that the activity of proteases depended on hydrothermal conditions.