Influence of nitrogen fertilizers on the biological activity of the soil of the rapeseed root zone

Abstract

Soil microbiocenosis is a dynamic, well-balanced system with a complex spatial and trophic organization. The main biosphere function of soil microbiocenosis is the destruction of organic matter. The polyfunctionality of microorganisms in the rhizosphere gives them the opportunity to participate in opposite biochemical reactions of the soil, which underlie the preservation of metabolic equilibrium in nature. Agrotechnological methods of growing rapeseed require high doses of mineral fertilizers, especially nitrogen fertilizers. The use of high doses of nitrogen mineral fertilizers leads to changes in the balance of the chains in the ecosystem, including microbiological activity. It is microbiological activity that is the reactionary force that quickly reacts to external factors. Method: In our work, a study of the biological activity of the soil of the root zone of rapeseed for the action of nitrogen fertilizers is presented. The study was carried out in the soil of temporary field experiments on agrocenosis of winter rapeseed, variety Black Velikan. The conditions of the experiment assumed the introduction of nitrogen fertilizers – 120, 150 and 180 kg/ha. The control option did not include fertilization. Determination of the biological activity of the soil in the root zone of rapeseed plants included the determination of the microbial biomass of carbon, the intensity of carbon dioxide emission, antifungal and cellulolytic activity, and the phytotoxicity of the soil. Results: The study of the soil of the root zone of rapeseed plants showed a directly proportional relationship between the dose of nitrogen fertilizer applied and biological activity. It was revealed that the fungistatic status of the soil of the root zone of rapeseed plants under the condition of applying nitrogen fertilizers in comparison with the control grew by 2.3–5.5 times; cellulosic activity by 1.5, the intensity of carbon dioxide emission increased by 2.1 –3.6 times. Conclusions: The content of microbial biomass was recorded at a high level; studies have shown that the content did not depend on the amount of fertilizers applied. Thus, the indicators of the biological activity of the soil of the root zone of rapeseed plants in the flowering phase indicate that the physiological and metabolic activity of microbial communities is at a high level and depends on exogenous sources of nitrogen.

Soil microbiocenosis is a dynamic, well-balanced system with a complex spatial and trophic organization. The main biosphere function of soil microbiocenosis is the destruction of organic matter. The polyfunctionality of microorganisms in the rhizosphere gives them the opportunity to participate in opposite biochemical reactions of the soil, which underlie the preservation of metabolic equilibrium in nature. Agrotechnological methods of growing rapeseed require high doses of mineral fertilizers, especially nitrogen fertilizers. The use of high doses of nitrogen mineral fertilizers leads to changes in the balance of the chains in the ecosystem, including microbiological activity. It is microbiological activity that is the reactionary force that quickly reacts to external factors. Method: In our work, a study of the biological activity of the soil of the root zone of rapeseed for the action of nitrogen fertilizers is presented. The study was carried out in the soil of temporary field experiments on agrocenosis of winter rapeseed, variety Black Velikan. The conditions of the experiment assumed the introduction of nitrogen fertilizers – 120, 150 and 180 kg/ha. The control option did not include fertilization. Determination of the biological activity of the soil in the root zone of rapeseed plants included the determination of the microbial biomass of carbon, the intensity of carbon dioxide emission, antifungal and cellulolytic activity, and the phytotoxicity of the soil. Results: The study of the soil of the root zone of rapeseed plants showed a directly proportional relationship between the dose of nitrogen fertilizer applied and biological activity. It was revealed that the fungistatic status of the soil of the root zone of rapeseed plants under the condition of applying nitrogen fertilizers in comparison with the control grew by 2.3–5.5 times; cellulosic activity by 1.5, the intensity of carbon dioxide emission increased by 2.1 –3.6 times. Conclusions: The content of microbial biomass was recorded at a high level; studies have shown that the content did not depend on the amount of fertilizers applied. Thus, the indicators of the biological activity of the soil of the root zone of rapeseed plants in the flowering phase indicate that the physiological and metabolic activity of microbial communities is at a high level and depends on exogenous sources of nitrogen.