AGROECOLOGICAL ASPECTS OF SOWING DATE AND SOWING RATES OF DIFFERENT WINTER BARLEY VARIETIES

Effects of early and late sowing date, high and low sowing rates were studied in winter barley considered as very risky cereal crop, through the method of field trials performed during five years. The varieties used were as follows: the Borwina, Ermo, and Sigra varieties. The trials were carried out under unfavourable weather conditions during first three years, i.e. under intensive drought, high evaporation rate and hard-to-cultivated soil for sowing. Two last years were good for germination, emergence and soil cultivation. The following factors were determined: numbers of plants at the beginning of the spring growing season, ear area, kernel percentage and thousand-kernel weight at the harvest. The results demonstrated unambiguously that the sowing date is to be chosen on the basis of ecological conditions - the drier autumn and evaporation rate, the later sowing at the simultaneous higher sowing rate of 5.5 million of germinating grains per ha. Under favourable moisture and soil conditions, it is necessary to sow early that is large-grained varieties at lower sowing rate of 3.5 million and small-grained varieties with increased sowing rate (5.5). The proportion of components of cultural practices and years were determined on the yield increases for the varieties under study in different years. The results showed that winter barley is not left behind the yields, it has even higher yields than winter wheat.