Responsiveness of oil flax varieties to increasing rates of mineral fertilizers

In the technology of oilseed flax cultivation, the use of fertilizers is of great importance. The effect of this factor is associated with varietal characteristics and soil and climatic conditions. In the northern forest-steppe of the Tyumen Region in 2019-2020 in field experiments on leached chernozem, the reaction of oil flax varieties August and Lehur to increasing rates of mineral fertilizers was studied. The years of research varied in meteorological conditions. The growing season of 2019 was characterized by the best provision of precipitation. The effect of fertilizers under these conditions was manifested in the variety August in the variant with a fertilizer rate based on the seed yield of 2 t/ha (+0.29 t/ha) and in the variant with a higher norm - NPK per 3 t/ha (+0.56 t/ha). In the Lehur variety, the increase in yield from the effect of fertilizers was 0.44 t/ha. The number of productive plants under the influence of fertilizers increased under the conditions of 2019: in the August variety by 34 and 23 pieces/м2, in the Lehur variety - by 34 and 25 pieces/м2. In 2020, no definite pattern was found in the change in the indicator under consideration depending on the effect of fertilizers. The mass of seeds per plant increased in the variants with fertilizers relative to the control. In 2019, for the August variety in the control variant, the indicator was 0.58 g, in the variants with fertilizers - 0.62 and 0.63 g. For the Lehur variety, the indicators for the experimental variants corresponded to the following values: 0.50 g; 0.60; 0.59 g. In 2020, the weight of seeds per plant in flax varieties slightly differed from the corresponding values in 2019. The highest oil content of seeds was observed in variety August in the control variant - 48.8 %. There was a decrease in the value of the indicator for this variety in variants with fertilizers.