VARIABILITY OF THE YIELD OF SPRING BARLEY AGAINST THE BACKGROUND OF DIRECT SOWING IN THE CONDITIONS OF THE SOUTHERN URALS

The laboratory of agrolandscape farming of the Chelyabinsk Research Institute of Agriculture during 2014–2022 conducted research to substantiate the effectiveness of cultivating spring barley on leached chernozem in the forest-steppe agrolandscape of the Southern Urals. High productivity of spring barley of the Chelyabinsky 99 variety was obtained against the background of systematic direct sowing when placing the latter crop in four-field crop rotations on various backgrounds of mineral nutrition. The yield potential of spring barley in the region under production conditions is mainly realized at 30–40 % of that declared by breeders and has strong variability depending on the growing season conditions of the year. The influence of four-field field crop rotations on productivity and economic efficiency was determined against a natural background of fertility and with the application of nitrogen mineral fertilizer in doses of N40-50, depending on the predecessor. The production of spring barley grain was profitable in field crop rotations, regardless of the background of mineral nutrition and amounted from 40 to 63 % against the natural background, and 53 to 73 % when nitrogen fertilizer was applied. Meeting the nitrogen nutrition needs of spring barley allows, under direct sowing conditions, to maximize the yield potential by an average of 58 %. Additional nitrogen nutrition contributed to a reduction in yield variability by 10 % and made it possible to reveal the potential of the crop presented by breeders on average over nine years to 56 %, in the most favorable years – up to 84 %.