Effectiveness of the mineral fertilizer system with different saturation in the link of the flax crop rotation

In the link of flax crop rotation (fallow land–winter rye–perennial grasses of the 1st year of use (y. u.)–perennial grasses of the 2nd y. u.–fiber flax) on sod-podzolic light loamy soil in the conditions of the Non-Chernozem zone of the Russian Federation in 2019–2023 the effectiveness of a mineral fertilizer system with different saturation of 1 ha of crop rotation was studied squares. It is shown that the highest yield of winter rye of 26.9 c/ha was obtained when applying fertilizers at a dose of N80P60K90, which corresponded to the option of applying 140 kg of active substance (a. s.) NPK/ha of crop rotation area. The optimal dose of fertilizers for perennial grasses of the 1st and 2nd y. u. was the use of N10P40K60, which provided hay yields of 38.6 and 52.0 c/ha, respectively. For fiber flax, the optimal dose was the introduction of N20P50K90, which made it possible to obtain the highest yield of flax straw 43.5 and flax seeds 5.3 c/ha. An increase in the dose of fertilizers for perennial grasses did not provide a reliable increase in yield, for fiber flax – led to a decrease in seed productivity. For perennial grasses and flax, it was sufficient to add 120 kg of a. s. NPK/ha of crop rotation area. The optimal saturation for the crop rotation link was characterized by a dose of 120 kg a. s. NPK/ha of crop rotation area. The productivity of the crop rotation link was 25.8 grain unit (g. u.)/ha, the payback of 1 kg of NPK was 10.7 kg g. u. On soil with a high content of mobile phosphorus, elevated and high potassium, an increase in the saturation of the crop rotation link with fertilizers up to 140 kg a. s. NPK/ha of the crop area did not provide a significant increase in productivity and led to a decrease in the payback of fertilizers with crop additions.