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Table 2 – The effect of fertilizers on the content of heavy metals in meadow-chestnut soils, mg/kg of soil (average for 2019-2020)
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- Table 3 – The content of mobile forms of heavy metals in meadow-chestnut soil, mg/kg (average for 2019-2020)
- Table 4 – Activity of meadow-chestnut soil enzymes in the application of various doses of mineral fertilizers
- Table 5 – Effect of fertilizers on the mesofauna of meadow-chestnut soils
- Table 6 – the Accumulation of heavy metals by soil invertebrates representatives of different functional groups on the motorway (mg/kg dry weight)
Table 2 – The effect of fertilizers on the content of heavy metals in meadow-chestnut soils, mg/kg of soil (average for 2019-2020)
This is due, apparently, to the biological feature of the plant, the root secretions of which have an acidic reaction of the medium. On the fertilized variants, a higher yield and a powerful root system are formed, which, apparently, reduces the negative impact of HM despite the high level of fertilizer use – 210 kg of d. v. phosphorus per 1 ha. It was found that against the background with the introduction of rotted manure, as evidenced by the receipt of small amounts of HM with manure into the soil. Mineral fertilizers applied separately do not significantly affect the change in the content of HM in the soil. The introduction of mineral fertilizers contributed to the change in the content of heavy metals (Table 3). Table 3 – The content of mobile forms of heavy metals in meadow-chestnut soil, mg/kg (average for 2019-2020)
According to the grouping of soils by level of contamination, the content of cadmium in soils varies from low to medium, lead from medium to high, and the level of contamination with zinc and copper is low. Our studies took into account the activity of soil enzymes in the variants where mineral fertilizers were applied. It was found that there is a decrease in the activity of enzymes when applying triple doses of fertilizers compared to the control (Table 4). Table 4 – Activity of meadow-chestnut soil enzymes in the application of various doses of mineral fertilizers
Dehydrogenase and catalase react poorly to changes in the content of HM in the soil. Invertase and urease enzymes react more, where their lowest enzyme activity is observed in the variant with high doses of fertilizers – 8.8 and 0.99 mg, respectively. In the study of soil mesofauna, the methods of layer-by-layer sampling of soil samples with a size of 50×50 cm in the field were used, which are generally accepted in soil-zoological studies. Excavations were carried out three times a season to study seasonal fluctuations in population. The number of soil invertebrates was determined by the direct accounting method – the number of objects taken into account per unit of soil surface area (ex/m2). The main part of the mesofauna was concentrated in the upper layers of the soil (0-10; 10-20 cm), then up to 40 cm there were single specimens. More species have been recorded on fertilizer variants. There are more numerous species from the family Carabida, Scarabaeidae. Therefore, the application of optimal doses of organic and mineral fertilizers does not significantly affect the complex of soil mesofauna. However, it has a positive effect on the condition of plants, which leads to an increase in the overall productivity of the agrocenosis and some changes in microclimatic conditions. As a result of fertilization, the biomass of plants increases by 2 times. All this leads to changes in microconditions on the soil surface and in its upper layers. In our experience it was found that resettlement of mesofauna in the study plots indicates the timing of application of organic and mineral fertilizers, which helps to improve vital activity of soil invertebrates, which in turn depend on optimization of many of the main agrophysical and agrochemical soil properties (density, specific gravity, soil moisture, soil pH, a sufficient amount of root and crop residues, the maximum allowable rate of heavy metals and radionuclides), (table 5). Table 5 – Effect of fertilizers on the mesofauna of meadow-chestnut soils
From the table data, it can be seen that the total number of mesofauna in the variant with manure (N2P2K2 Н2) was-406.0 ex/m2, while in the control variant (without fertilization) their number was – 258.0 ex/m2. One of the most toxic substances that enter the biosphere in the results of human production activities can be attributed to heavy metals. In small amounts, they are found in every organism [10]. Heavy metals accumulate in the soil and litter, plants and animals, and enter the human body, causing poisoning and diseases The role of animals in the biogenic migration of substances in terrestrial ecosystems is poorly understood. The activity of animals in biogeocenoses can be considered as a factor regulating this biogenic cycle. Comparative analysis of heavy metals content from representatives of various functional groups of invertebrates shows that cadmium, in comparison with all micronutrients accumulates animals in the smallest quantity (1.1 to 9.1 mg/kg dry mass) (table 6). Table 6 – the Accumulation of heavy metals by soil invertebrates representatives of different functional groups on the motorway (mg/kg dry weight)
In connection with the above, the importance of these groups of invertebrates in the migration of heavy metals through food chains, including vertebrates, is difficult to overestimate. In the future, it is necessary to continue monitoring the migration of heavy metals in biogeocenoses, including trophic networks. And also to identify the main factors that determine the processes of bioaccumulation and biomagnification. The obtained data can be used for bioindication and monitoring studies of environmental pollution both in the region and abroad. жүктеу/скачать 2,01 Mb. Достарыңызбен бөлісу:
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