Effect of biohumus based on poultry waste on physico-chemical properties of sod-podzolic soils and cultivated plants

Introduction. The current phase of mass production in the poultry products sector creates large volumes of waste in the form of chicken manure. This waste contributes to the negative environmental impact on the neighboring territories. To address the issue of storing chicken manure, several methods have been developed, of which incomplete combustion and composting with gradual decay are two major ones. The application of both technologies results in the production of fertilizers such as mineral biochar and organic humus. The role of these fertilizers is particularly important for regions that face the challenge of insufficient fertility of the zonal soil type, a concern that is common in some mountainous regions. The goal of the study is to develop a method and analyze the results of its application to successfully solve the problem of excess chicken manure by producing a substance that improves the physicochemical properties of sod-podzolic soils and increases their biological efficiency. Materials and methods. The laboratory facilities of the Ecosystem Research Center at St. Petersburg Mining University were used in this study. The physicochemical properties of soils and plants were analyzed based on a standard method for determining the organic content of soils using gravimetric, thermogravimetric, and optical emission spectrometry methods. Results and discussion. Given the relatively low fertility of sod-podzolic soils, which are common in mixed forest regions, the article proposes a modified version of composting as a priority for processing poultry manure. This method accelerates the biochemical processes of manure decay by using a specially bred subspecies of the earthworm Eisenia fetida. The article provides a detailed description of this method for processing poultry manure, which results in the production of an organic fertilizer. To evaluate the effect of the biofertilizer produced by the proposed method on the physicochemical properties of sod-podzolic soils and the plants grown on them, we conducted an experiment involving the addition of the biofertilizer to the soil, followed by sowing ryegrass and spring onion seeds, followed by an analysis of soil and plant samples. The results of the experiment showed that the presence of the biofertilizer in the soil increases its moisture content, improves moisture retention, and reduces ash content. The addition of the biofertilizer significantly increases the contents of humus, organic carbon, total nitrogen, phosphorus, and potassium, also promoting the removal of heavy metals. The use of the proposed biofertilizer enhances the uptake of carbon, nitrogen, and potassium into plants. The proposed method is adapted to residential area conditions and can be used by agricultural companies in various regions of Russia. A future line of research includes experiments to find the rational biofertilizer application rates for growing more common vegetable and grain crops in soils of different types. Conclusions. The study has developed a comprehensive method for investigating the processes of transfer of organic matter and chemical elements from the proposed biofertilizer into soils and plants. This method includes laboratory tests of the physicochemical properties of soils before and after the experiment and those of fertilizers and plants after the experiment. The results demonstrate that the presence of the biofertilizer in dry sod-podzolic soils increases their fertility and improves the physicochemical properties of both the soils and the plants. Resume. The proposed method is adapted to residential area conditions and can be used by agricultural companies in various regions of Russia. A future line of research includes experiments to find the rational biofertilizer application rates for growing more common vegetable and grain crops in soils of different types.