BIOLOGICAL NITROGEN FIXATION AS A WAY OF INCREASE YIELD OF SOY

Abstract

The article highlights the importance of soybeans as one of the main agricultural crops for the life support of society with food. It is well known that soybeans have been the main high-margin crop for many global farmers, including Ukraine, in recent years. The interest in this crop continues to grow as new opportunities for its sale abroad open up, especially in such a giant country as China, the world's largest soybean importer. The right variety accounts for more than 50% of production success. It is important to identify and create optimal conditions for realising the potential nitrogen-fixing activity of soybeans of each variety in specific soil and climatic conditions. Scientists have pointed out that the main reasons that significantly limit symbiotic fixation in our conditions are relatively drier soybean cultivation conditions, especially in the face of abrupt climate change. However, it is also noted that the starting rates of nitrogen fertilisers + symbiotically fixed nitrogen can only offset part of the soybean plants' need for a yield of 4.0 t/ha. The air contains about 76% of nitrogen in the form of N2 gas, which is not available for plant nutrition. However, thanks to the unique ability of legumes to form symbiotic relationships with bacteria of the Bradyrhizobium and Rhizobium genera, N2 gas is converted into an ammonium form of nitrogen suitable for plant use. This interaction takes place in the nodules, which contain the respective bacteria. According to established data, up to 70% of the total nitrogen consumption of soybeans is obtained through biological fixation of nitrogen from the air through symbiosis with nodule bacteria. Based on the analysis of scientific publications on the symbiotic productivity of soybean crops in Ukraine and the world, the indicators of biological fixation by soybean crops in the context of the main soybean producing countries are presented and the importance of soybean cultivation in Ukraine is proved. It is confirmed that soybeans are an important strategic crop in Ukraine, which contributes to the stabilisation of agriculture, increase of soil fertility and nitrogen reserves, eliminates protein deficiency and helps to solve the food problem. The increase in gross soybean harvest is not only due to the expansion of sown areas, but also due to higher yields. To increase the efficiency of soybean production, it is proposed to introduce a set of innovative solutions at different stages of production, as well as to use new, productive varieties. In many publications, the authors emphasise that 30-35% of success in soybean cultivation depends on the right choice of variety and optimally selected technological methods of growing this crop.