Influence of biologisation of the nutrition system on the transformation of biological nitrogen and formation of soybean productivity

Rising prices for mineral fertilisers stimulate the search for alternative ways to optimise the existing and develop new technological methods of growing crops, including soybeans. One of these approaches is the intensive use of biological ways to enhance the ability of legumes to symbiosis and natural fixation of biological nitrogen from the soil air, which will help reduce the cost of plant cultivation technology. That is why the purpose of this study was to determine the effect of biological preparations on atmospheric nitrogen fixation by soybean plants using symbiotic nodule bacteria. In these studies, the method of calculation based on active symbiotic potential and symbiotic specific activity was used to determine the amount of biologically fixed nitrogen. The study analysed the effect of some inoculants and biofertilisers intended for foliar application on the development and formation of symbiotic processes in soybean plants, namely, the specific features of the formation of both general and active symbiotic potential in the vegetation stages. The influence of symbiotic productivity on soybean grain yield was also determined. Treatment of seeds with the selected preparations for the entire period of symbiosis duration provided an increase in the total symbiotic potential and active symbiotic potential. It was found that the treatment of seeds with the inoculant Bioinoculant BTU (2 l/ha) before sowing was more productive. Therewith, the maximum soybean grain yield of 3.31 t/ha was recorded in areas where the preparation Bioinoculant BTU (2 l/t) was treated before sowing and two fertilising applications were made in the 3rd ternate leaf stage and in the budding stage with Helprost soybean fertiliser (2.5 l/ha). The findings of this study indicate a substantial impact of symbiotic productivity and its value on soybean grain yield. Correlation and regression analyses showed that the accumulation of biological nitrogen has a considerable impact on grain yield. Thus, the use of biological preparations is an alternative to mineral fertilisers in soybean cultivation technology and they can be implemented in the production conditions of agricultural enterprises