Comparative characteristics of planting material of silver birch grown from seeds of autumn and spring sowing

Annual seedlings of silver birch ( Betula pendula Roth.), grown from seeds of autumn and spring sowing period, were analyzed. Planting material was kept in protected ground. Before sowing, various growth substances were incorporated into the soil - mineral and organic fertilizers, forest soil. It was revealed that autumn sowing increased the height of seedlings 1.03…1.66-fold in the variants compared to the control, except for the variants with the use of nitrogen and phosphorus fertilizers, where the largest number of plants per unit area was observed. In the variants with Humatophosphate, boric acid, Trichocin, humus and forest soil, from 60 to 100 % of seedlings reached standard values in a year. A similar experiment with the same growth substances, but spring sowing of seeds, showed a significant lag in seedling growth. The use of nitrogen fertilizer in spring, in contrast to the autumn period, had a positive effect on plant height, annual seedlings had the highest height in the experiment - 14.1 cm. Seedlings in variants with humus and forest soil also had good indicators. All variants overtook the control seedlings in height by 1.06…2.68 times. Therefore, the time of sowing seeds is important - all indicators of autumn seedlings significantly exceed the similar ones of spring seedlings. This fact is explained by several reasons: during the autumn period, the seeds are sown freshly harvested, they undergo pre-sowing preparation (snowing and stratification) in natural conditions, the seeds are not stored, in case of violation of which the seeds significantly lose their germination capacity. In addition, the seeds begin to germinate and shoots begin to grow much earlier than if they were sown in the spring. Shoots are not exposed to late spring frosts, as they are protected by covering material.