Abstract
Melilotus is a perennial legume plant that is valuable for fodder production due to its drought resistance and ability to accumulate biological nitrogen in the soil. In the rice crop rotation conditions of the Kyzylorda region, where soils are characterized by salinity, melilot can play a key role in increasing the productivity and sustainability of the agroecosystem. The aim of this study was to investigate the effect of different doses and combinations of organic and mineral fertilizers on the growth, development, productivity, and feed value of sainfoin in the region's saline meadow-marsh soils. The research methods included field experiments with the application of phosphorus fertilizers at doses of P60 and P120, as well as their combinations with organic fertilizers (manure 15 t/ha). Agrochemical analyses of soil and plants were carried out to assess nutrient content. The productivity of sainfoin was assessed by the yield of green mass, hay, and seeds, as well as by the digestible protein content. The results showed that the application of phosphorus fertilizers at doses of P60 and P120, both alone and in combination with manure, significantly increases the yield of sainfoin. The greatest effect was achieved when P60 was applied in combination with manure, which ensured maximum green mass yield of up to 376,6 c/ha and hay yield of up to 87,7 c/ha, as well as digestible protein content of up to 608,4 kg/ha. The scope of application of the research results includes the development of effective agrotechnical measures to increase the productivity of sainfoin in saline soils of arid zones, which contributes to the improvement of the feed base for livestock and the sustainability of agroecosystems.