Comparative effectiveness of the use of mineral and organic fertilizers in the cultivation of onions in an annual crop

We conducted a comparative study of the effect of mineral and organic fertilizers on the yield and quality of 5 medium-ripened domestic onion varieties in an annual crop on the alluvial meadow soil of the Moscow region. Laboratory and field experiments were carried out by the Department of Agriculture and Agrochemistry of the VNIIO branch of the FNCO in 2020–2022 on sufficiently cultivated medium-loamy alluvial meadow soils of the central part of the Moskvoretsky floodplain. In the experiment with the 5th varieties and the 3rd variants of the mineral fertilizer system, the commercial yield of onions was 53.0 t/ha, whereas with the use of an organic fertilizer system – 58.4 t/ha. Accordingly, the increase in yield relative to the control without fertilizers in the first case was equal to 106, in the second – 117%, marketability – 93 and 95%. It has been established that when determining the need of plants for nutrients during the growing season, it is preferable to use methods of leaf diagnostics. On average, for 5 varieties of onion, the yield increase, according to the results of plant diagnostics, turned out to be 13% more than in variants with NPK doses calculated according to soil diagnostics. Biochemical quality indicators for all onion varieties and all fertilizer variants did not differ statistically significantly from the control. The quality of onion products practically did not depend on the applied fertilizer systems. The organic fertilizer system provided the best supply of nutrients to onions in the phase of the beginning of bulb formation, which was crucial for obtaining the greatest yield in an annual crop. On average, for 3 variants of the organic system, the soil contained 2.34 mg/100 g of mineral nitrogen in the phase of the beginning of bulb formation, whereas with the use of the mineral system – 1.65 mg/100 g, or 42% less.