Phytosanitary condition of barley crops in crop rotation depending on the elements of cultivation technology

The studies were conducted to identify the impact of growing conditions on field germination of barley and resistance to dangerous pathogens in the initial period of the development.The studies were conducted in 2014-2018 on the experimental field of the Smolensk State Agricultural Academy. The soil of the experimental plot is sodpodzol, middle-loamy, cultivated soil, slightly acidic (рНKCl= 5.8-6.0). The depth of the arable horizon is 20-25cm. Before conducting the experiments, soil samples were selected and analyzed. The content of the nutrients were: humus - 2.00-2.10%; mobile phosphorus - 148-152 mg per 1 kg; exchangeable potassium - 163-170 mg per 1 kg of completely dry soil.In experiment 1, field germination depending on the year changed slightly V = 7.79-11.7%, depending on the seeding rate V = 2.5-9.8%. Early sowing terms provided the most friendly germination of barley seeds. In the experiment 2, the biological effectiveness of pretreatment was higher in variants with infected seeds; pretreatment of healthy seeds did not always have a positive phytosanitary effect, especially with deeper incorporation. Pretreatment with RaksilUltra at the rate of 0.5 l/t increased the germination rate by 16-50% if infestation of seeds is above the threshold of harmfulness, especially when the depth of sowing is greater. In the variants with healthy seeds, the increase in germination was less significant (8-12%). The pretreatment stimulated the development of underground organs of barley seedlings, the length of the embryonic roots, especially at a lower depth of sowing, increased. Maximum development of common blight reached the epicotyl of seedlings, which exceeded the threshold of harmfulness (15%) in 2-2.5 times, particularly in the variants without treatment.