SUNFLOWER PRODUCTIVITY ON LEACHED CHERNOZEMS IN LONG-TERM EXPERIENCE WITH FERTILIZERS
During 5 rotations of ten-field rotation in stationary field experiment the influence of annual application of fertilizers on productivity and quality of sunflower seeds (Helianthus annuus L.) was studied. The dynamics of the nutrient regime in the soil layers of 0-25 and 25-40 cm during the vegetation period was studied. It is shown that the optimal dose of fertilizers for sunflower should be considered N<sub>60</sub>P<sub>60</sub>K<sub>60</sub>, which provides an increase in yield by 0.4-0.7 t / ha, while the oil collection increases by 25% compared to the non-porous background (0.8 t/ha). Economic takeaway from biological, taking into account the root system on a natural background, was 50 % nitrogen, 54 % phosphorus and 12 % potassium and was almost the same against the background of N<sub>60</sub>P<sub>60</sub>K<sub>60</sub>, respectively, the elements: 48%, 51% and 9%. The change in the ratio of nitrogen, phosphorus and potassium in the complete fertilizer did not effect the oil collection. Application of phosphorus and potassium fertilizers separately was inefficient. Increasing the dose of fertilizers is not economically feasible.