EFFECT OF SOWING TIME AND SEED RATE O THE PRODUCTIVITY OF WINTER WHEAT

Abstract

For winter wheat in autumn, it is particularly important to choose the optimum sowing time and seed rate for maximum grain yields. The main objective of this study was to determine the influence of sowing time and seed rate on crop productivity. The field experiment was carried out between 2023 and 2024 at the Experimental Station of the Academy of Agriculture of Vytautas Magnus University. The experiment is a two-factorial design. Factor A - seed rate, factor, B - sowing time. In the experiment, winter wheat was sown at four different sowing dates: 7, 14, 21, 28 September and at four seed rates: 5,0; 4,0; 3,0; 2,0 million seeds ha^-1. Each variant was installed in six replications. Winter wheat density was determined three times during the growing season (BBCH 30–32, BBCH 57–58 and BBCH 84–87). The soil of the field experiment had a medium loam soil grain size composition. The topsoil has a neutral reaction (pH 7,1), medium humus content (1,85 %), high phosphorus content (P₂O₅ 234 mg kg^-1) and medium calcium content (K₂O 126 mg kg^-1). The selected variety is 'Skagen'. Winter wheat was fertilised with N₁₇₂, P₃₆, K₃₆ kg ha^-1 throughout the growing season. At BBCH 30–32, the densest crop was formed in the optimum sowing (14 September) at a rate of 5 million seeds ha^-1 (1384 stems), and the sparsest crop was formed in the early sowing (7 September) at a rate of 3 million seeds ha^-1 and in the late sowing (28 September) at a rate of 4 million seeds ha^-1. The second measurement (BBCH 57–58) showed a reduction of between 10.0 and 49.4 % of the stems compared to the first measurement. The third measurement (BBCH 84–87) showed that the significantly densest crop (720 stems m^-2) was formed in the late sown wheat at the rate of 5 million seeds ha^-1. Significantly the highest yields were found in the optimum sowing (21 September) at 5 and 4 million seed units per ha^-1 rate.