Advances in Biology & Earth Sciences

Spring barley is threatened by net blotch (NB) and spot blotch (SB), reducing yields by up to 60%. A 2022-2024 trial at the Russian Federal Research Center, Nemchinovka, evaluated foliar sulfur (Ultramag SuperSulfur-900) and fungicides on two genotypes (Nadezhny, Nur) under seven treatments: control; 0.5 l ha^-1 Alto Super; 0.4 l ha^-1 Colosal Pro; 1.0 L ha^-1 Capella, ME and each fungicide + 3.0 l ha^-1 Ultramag SuperSulfur-900, in a split-plot design with three replications. Colosal Pro + Ultramag SuperSulfur-900 provided the best SB control in Nur, reducing incidence and severity by 78.3-89.4%, outperforming Alto Super + Ultramag SuperSulfur-900 (77.5-84.6%) and Capella + Ultramag SuperSulfur (60.0-79.9%). Combined treatments significantly (p < 0.05) increased yield by 9.81% (Nadezhny) and 15.59% (Nur). The highest mean yields were recorded with Colosal Pro + Ultramag SuperSulfur-900: 6.49 t ha^-1 (Nadezhny) and 5.19 t ha^-1 (Nur). Yield correlated positively with 1000-grain weight (r = 0.90***), grains per spike (r = 0.80***) and negatively with SB (r = -0.87 to -0.89***). Yearly variability was climate-driven. Economic analysis showed that Colosal Pro alone maximized profitability; all combinations with sulfur failed to consistently improve returns. Nadezhny outperformed Nur in yield and income. Profitability depends on genotype disease pressure and cost benefit balance not just yield so inputs should be tailored annually and evaluated economically.