Effect of disturbed irrigation regime on the yield of Sudan grass, grown for the Southern Bulgaria environmental conditions

The aim of this study was to determine the effect of disturbed irrigation regime on dry biomass yield of Sudan grass. In the period 2021 - 2023 for the region of Stara Zagora on meadow - cinnamon soil was conducted an experiment with Sudan grass variety Endje - 1, grown after the precursor barley. The following variants were studied in the field trial 1 No irrigation (control), var. 2 Optimal irrigation 75-80% of FC (100% irrigation rate), var. 3 Irrigation with 70% of calculated irrigation rate, 4 Irrigation with 40% of calculated irrigation rate. It was found that the highest average yield of 13940 kg/ha dry biomass was obtained with the optimally irrigated variety, which was 36.5% higher than the yield of the non-irrigated variety. When the irrigation rate is reduced by 30% compared to the optimal option 1 (100%), the dry biomass yield decreases by 8.5%.