ENZYMATIC ACTIVITY OF SOILS IN A FLOODPLAIN ECOSYSTEM

The paper presents the results of studies on the biological activity of peat soils in the near-terrace part of the Kii river floodplain (Ob River basin, Tomsk region). Indicators of their fertility are given based on the fractional composition of organic matter and nitrogen. The range of changes in enzymatic activity in floodplain virgin peat soils was determined: invertase 36.3–42.2 mg glucose/(g*4 h)), urease 0.3–1.5 mg NH3/(g*24 h), catalase 0.6–2.6 cm3 O2/(g*2 min), ferrireductase 75.3–120.0 mg reduced Fe2+/100 g, sulfate reductase 1.5–8.0 mg reduced SO42-/( g*48 h); nitrate reductase 0.2–0.8 mg reduced NO3—/(g*24 h), nitrite reductase 0.8–1.4 mg of reduced NO2—/(g*24 h), peroxidase 0.27–0.39 mg l.4 n-benzoquinone/(g*30 min), polyphenol oxidase 0.25–0.40 mg l.4 n-benzoquinone/(g*30 min). It was found that the drainage system with a drainage option of 0.8×25 m created the proper level of optimization of the biological regime in drained floodplain peat soils and provided a high yield of perennial grasses. The process of activation of the biological regime was realized over a 3-year period at the stage of hydrolase enzyme activity. The research clearly demonstrated the importance of the enzymatic factor as an indicator of the ecological state of peat soils. It was revealed that existing assessments of enzymatic activity for mineral soils are not suitable for assessing the biological state of peat soils and therefore in the future it is necessary to develop it directly for peat soils.