Sugar beet (Beta vulgaris L.) requires fertile soils with high biological activity, rich in minerals and organic nutrients. Biological properties of soil, such as enzymatic and microbial activity, can be effectively improved through the application of humic substances. This enables an increase in growth dynamics and, consequently, in the yield. The aim of this study was to assess sugar beet germination, depending on the soil application of the humic preparation Humistar (12% of humic acids, 3% of fulvic acids) as well as to assess the yield of sugar beet storage roots and the content of sugar in these storage roots, depending on soil applications of Humistar and/or foliar application of potassium fertilizer Drakar (31% K2O, 3% N). The field experiment was conducted in the soil classified as Mesic Typic Hapludalfs. Soil application of Humistar contributed to a reduction in sugar beet germination, measured as % of plants germinated within 14 days after sowing. However, the growth of plants in soil with Humistar was more intensive than in the control. A significant, positive influence of Humistar and Drakar on the yield of sugar beet roots has been found. Application
of the two treatments did not produce better results than the use of each of them separately. Sugar content in roots was not affected by experimental factor. The study showed that both soil application of humic substances and the use of foliar potassium fertilizer can improve the yield of sugar beet and, consequently, increase the biological yield of sugar from storage roots.
