Nutrient regime and balance of nutrients in soil under forage crops under application of different types of fertilizers (on the example of Kyzylorda region)

Modern agriculture is facing a number of challenges, among which the efficient use of fertilisers to provide plants with the necessary nutrients is of particular importance. In particular, the growing focus on sustainable agriculture and the need to preserve soil resources underline the relevance of research into optimising fertiliser use. The purpose of the study was to identify effective methods of fertiliser use to provide plants with nutrients. To achieve this goal, the effectiveness of green manure, organic (manure) and mineral fertilisers under Sorghum and perennial grasses (Medicago sativa, Elytrigia, Agropyron) on saline soil was investigated. The study founded that organic fertilisers, such as manure and green manure, contribute to a more even supply of nutrients to plants compared to mineral fertilisers. This is particularly important in the context of nitrogen and phosphorus balance, where Medicago sativa has a positive nitrogen balance due to its ability to symbiotically fix nitrogen. Other crops studied, such as Elytrigia, Agropyron and Sorghum, showed a negative nitrogen balance on the control variant, but the application of N100P50K110 mineral fertiliser resulted in a positive nitrogen balance. The replacement of mineral fertilisers with organic fertilisers such as manure and green manure increased nitrogen inputs but also increased nitrogen removal from the soil due to the increase in phytomass yields. The results of the study confirmed the importance of transitioning to a more sustainable and environmentally friendly way of production in agriculture, which will ensure the development of the industry and increase its competitiveness in the international market. The practical significance of the study is to provide farmers with the opportunity to increase the yield of their crops and at the same time preserve soil fertility through the optimal use of nutrients contained in fertilisers