Articles

The response of biological activity and the content of labile forms of biogenic elements in peats of different genesis to variation in their moisture content was studied under laboratory conditions. Samples of peat soils of the northern and southern taiga (Tyumen and Moscow regions) were used in this work. A series of manipulation experiments were conducted in which the dynamics of such indicators as basal respiration (BR), microbial biomass carbon, labile carbon and nitrogen content were estimated for different peat types at different moisture levels. The effect of the experiment duration and type on the dynamics of peat properties was also assessed. It was found that all the studied peat samples are characterized by a wide range of moisture content, at which the maximum of biological activity is observed. In general, it is in the range from 20–30% to 80–90% of water–holding capacity (WHC). In this range, no significant relationship is observed between moisture content and BR. In most experiments, a reliable decrease in biological activity was observed only in the "extreme" humidity ranges - less than 20% and more than 90% WHC. It is shown that the nature of the response to moistening is individual, determined by the properties of the sample and depends little on the type of sample preparation. In experiments and model calculations, it is proposed to use the obtained sensitivity coefficient to moisture — W₂₀, which is 1.0‒1.2 in the range of 40‒80% WHC for peat samples of different genesis. Long-term variants of incubation experiments showed a more pronounced response to overmoistening and a reliable decrease in biological activity at high humidity values (more than 80% WHC). This may indicate their better applicability for solving problems of modeling the behavior of ecosystems in the event of a change in the hydrological situation.

The article presents the results of the study of the dynamics of changes in agrochemical parameters of soils and soil cover structure changes as a result of hydrotechnical melioration, using the example of the experimental site of the agricultural organization “Bobrik”. It was established that over a 50-year period, the reaction of the soil changed from slightly acidic pH_KCl 5.5–6.0 (68.8% of the area of the farm under study (530 ha)) to neutral (pH_KCl 7.0–7.5) and slightly alkaline (рН_KCl 7.5–8.0), while the optimum for sandy soils is 5.5–5.8 рН_KCl. Optimum values were reached for potassium content in 2022, after many years of chemical treatment of the site as a whole, and 48.5% of the territory for phosphorus did not reach the range of optimal values. Analysis of the structure of the soil cover showed that the number of soil contours increased from 58 to 172 during economic use, and the average area of the ESA decreased from 15.93 ha to 6.34 ha. An increase in the heterogeneity of the soil cover leads to an even more active redistribution of substances, including excessive accumulation of fertilizers. Based on the calculated morphometric coefficients of the soil cover structure, it was established that only 146 ha (13.9% of the site area) can be effectively used as arable land for the restoration and rational use of the studied agrocenosis. Taking into account the agrochemical potential of lands recommended for removal from agricultural production due to very high heterogeneity of the soil cover, their area is reduced from 72.5 ha to 23.2 ha due to the inclusion of elementary plots with agrochemical parameters sufficient for meadow use.

The historical and modern concepts of fallow lands (abandoned cropland), the causes of their occurrence and some features of their functioning are considered. The main stages of the development of abandoned cropland are highlighted from the perspective of a consistent change of vegetation in agrophytocenoses that arise after the cessation of soil cultivation. The literature data and existing approaches to assessing the land area of arable land withdrawn from agricultural circulation are analyzed. The prospects of using abandoned fallow lands both in the agricultural sector of agricultural production and in the broader ecosystem plan are considered. Attention is drawn to the fact that deposits of different ages are, in fact, chronological sequences of various dynamic biogeocenoses with actively transforming plant and soil components, which make it possible to assess, among other things, the rate of soil formation and degradation processes.