Образования
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| Key words. soil, heavy metals, pollution, indication, agroecological assessment, mesofauna, enzymatic activity of soils, humus
Introduction. The activity of animals in biogeocenoses can be considered as a factor regulating this biogenic cycle [1]. The block of soil-litter invertebrates is characterized by an early reaction to the pollution of their habitat by heavy metals. It is known that representatives of mesofauna act as their active accumulators [2]. Of particular interest is the migration of trace elements along the trophic chains of these animals and other elements, both to determine their resistance to toxicants and to identify loads on the ecosystem as a whole [3]. So, in insects-representatives of the mesofauna, the concentration of heavy metals in food is one of the main factors that determines their content in the animal's body. Most studies on the accumulation of heavy metals by soil-bedding vertebrates are conducted near factories or highways. As a result of the changes that occur in the soil under the influence of the activity of soil animals (improvement of soil aeration, water permeability, creation of agronomically valuable soil structure, uniform mixing of organic and mineral particles, nitrogen enrichment, etc.), the overall fertility of the soil increases. This position is confirmed by many researchers who conducted special experiments mainly on earthworms In the field, many researchers observed more intensive growth of a number of plants in areas of active animal activity. In particular, Gilyarov M. S. [2] noted the best state of steppe vegetation in places with worm tracks; N. A. Dimo [3] made a similar conclusion in the desert zone for the places of settlement of termites and desert woodlice; Ponomareva S. I. [4] in the forests observed the best renewal of spruce in places inhabited by ants, worms or rodents. Soil fertility is affected not only by the course of decomposition and changes in organic residues in the soil under the influence of soil animals, but also by changes in the mineral part. Finally, we must stop at the change in the petrographic composition. Snails are known to enrich the soil with calcium carbonate in the form of aragonite shells. Earthworms contribute to the secondary formation of biogenic calcite in the soil [5] Earthworms not only bury stones, as was brilliantly described by Darwin, but are able to wear out, i.e. destroy them; Recent experiments have shown that as a result of passing through the intestines of worms for more than two years, basalt flour, taken in a mixture with straw as a substrate for the culture of worms, has changed greatly. In the "soil" formed by worms from basalt flour and rotting straw, which consisted of excrement, the percentage of individual compounds changed in comparison with the initial minerals (basalt flour). Significantly increased the content of СаО and only a few – one and a half oxides, decreased the percentage of SiO2, Na2O, K2O and MgO. This means that the destruction clearly affects the basalt [6,7]. The mechanical composition of the soil also changes when passing through the intestines of worms and other invertebrates, in particular, the content of clay colloidal particles increases. All these aspects of the activity of soil animals should attract the close attention of soil scientists, since they are important for soil fertility. Among the soil-dwelling animals there are a huge number of harmful species that feed on living plants, dangerous pests, the activity of which reduces the yield of cultivated plants, and in some cases makes it even impossible to cultivate them. In the studies of M. V. Dabakhovа [8], methods of biological assessment of the ecological state of park soils in Nizhny Novgorod (catalase, invertase, nitrification activity, СО2 emission intensity, cellulolytic activity) were tested in the framework of soil-ecological monitoring. It is established that the most interesting of the studied indicators that characterize the state of soils under the influence of HM are such as the activity of the enzyme catalase and the nitrifying ability of soils. When studying the change in the content of chemical elements in plants under the influence of various amounts of heavy metals in the soil, Grigoryan K. V. [9] found that the latter, along with the toxic effect on the plant itself, manifested in a decrease in the supply of elements necessary for the plant, sharply reduce the intensity of redox processes in the soil. Soil contamination with petroleum products occurs everywhere in large and small cities, around gas stations, the number of which increases every year, along roads, wherever there is oil-related human activity. Bioindicator types of soil biological activity under anthropogenic load on the soil, in particular with prolonged use of fertilizers, can respond to very weak effects due to dose accumulation. The use of living organisms as biological indicators for environmental change makes it necessary to develop a number of criteria on the basis of which indicator species can be selected. In this regard, we conducted research on the study and selection of soil bioindicators for agrocenoses of the south-east of the republic at different levels of mineral fertilizers application. жүктеу/скачать 2,01 Mb. Достарыңызбен бөлісу:
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