Seasonal Activity of Soil Peroxidase in Drained Swamp Pine Forests of Western Siberia: Systematic-Ecological Analysis

Abstract

We studied a mesotrophic swamp drained 25 years ago, in the northern part of the Ob and Tom rivers (geographical coordinates 56°23′710″ N, 84°34′043″ E). In forest peat soils (0–30 cm), the weighted average of peroxidase activity for the season (base level) was in the mode of weak hydro reclamation 14.4, moderate – 21.9, intensive 70 units (ml I/g of abs. dry sample in 2 min). Second-order parabola is a most adequate function of the main trend of the development of seasonal fluctuations in peroxidase activity. Numerical values and signs of the parabolic trend parameters show that from June to October, the average peroxidase activity decreased weekly by 4.4, 7.6 and 15.2 units with weekly average acceleration by 0.31, 0.59 and 1.54 units in the mode of weak, moderate and intensive drainage, respectively. The seasonal wave of peroxidase activity relative to the baseline level is characterized by a June increase in growth rates, the maximum in the 0–10 cm layer. In July, there is a decrease in the growth rate according to the depth of reclamation: in the mode of weak and moderate drainage the process already covers the entire soil profile in August, in conditions of intensive drainage – in October. The enzyme activity is significantly positively related with soil bulk moisture and pH, negatively – with redox potential and multidirectionally – with soil temperature. Environmental conditions act as duplicate parameters when assessing their contribution to the seasonal dynamics of peroxidase, creating the effect of interchangeability of environmental gradients. Canonical determination indices approximate the cumulative impact of the discussed set by 52–74%, depending on the depth of reclamation. Canonical weights show that the main factor regulating the seasonal activity of peroxidase is the hydrothermal regime. According to canonical correlations, in conditions of weak drainage, to a greater extent under the influence of temperature, intensive – humidity, moderate drainage – humidity and temperature. The differentiated contribution of peroxidase activity in the formation of the humus state of peat soils of different degrees of drainage was revealed.