Reaction of fiber flax varieties to seeding rates, sowing time and optimization of mineral nutrition on sod-podzolic medium- cultivated soils in the Pskov region

Abstract

The article presents the results of scientific research for 2014-2019 on the reaction of early-maturing fiber flax varieties (Linum usitatissimum L.) of the Pskov selection Peresvet, Kvartet, Voskhod and Dobrynya to growing conditions: sowing time, seeding rates (16, 18, 20, 22, 24 million pieces of germinating seeds per 1 ha), doses of nitrogen fertilizers (0, 15, 30, 45 kg of active ingredient (a. i.) per hectare. The hydrothermal coefficient (GTC) for the growing season varied from 0.98 to 1.94. The optimal seeding rate for fiber flax of the Peresvet variety is 22 million pcs /ha, and for the Kvartet variety − 20 million pcs /ha. With these seeding rates the yield of flax fiber was 21.9-20.6 hundred kilograms (centners) per hectare, respectively, that significantly exceeded the yield of fiber with the minimum seeding rate of 1,0-1.7 hkg/ha, respectively, with LSD05 = 0.7-0.9 hkg/ha. The maximum yield of seeds in both varieties was obtained at the minimum seeding rate. The optimal sowing period for the Peresvet variety was the third period (May 8-17th, 2014-2016) and the second period for the Kvartet variety (May 11-20th, 2017-2019). The yield of flax fiber for these varieties significantly exceeded the 1stsowing period by 0.7-2.3 hkg/ha, respectively (LSD05 = 0.6-0.8 hkg/ha ) and amounted to 23.0-21.1 hkg/ha , that of seeds – 9.8-9.1 hkg/ha. The optimal nitrogen doses for R40K60 background are for Voskhod and Kvartet varieties 15 kg a. i./ha, and for the Dobrynya and Peresvet varieties − 30 kg a. i./ha. The yield of flax fiber for them exceeded the control by 1.5-1.3 hkg/ha, respectively (LSD05 = 0.6-0.8 hkg/ha) and 2.7-2.5 hkg/ha (LSD05 = 1,0-0.9 hkg/ha). The payback of 1 kg of nitrogen by flax fiber increase in all varieties was the highest with the minimum dose of N15. Among the varieties, it ranged from 8 to 12.7 kg/kg. The specific removal of food elements per 1 ton of flax straw and flax fiber recommended for use in determining the doses of mineral fertilizers for the planned yield of flax fiber, has been determined.