Management of digestate from production of biogas has a great environmental importance. One of feedstock for biogas generation is beet pulp, a side product of sugar beet processing plant. In the paper a closed loop of beet pulp utilization at sugar beet plantation is presented. Effects of soil application of digestate obtained from digestion of sugar beet pulp were compared with standard mineral fertilizers. The field experiment was performed in three successive growing seasons. The studies were concentrated on quality of sugar beets grown under effects of two fertilization treatments—soil application of digestate cv. standard mineral fertilizers. It was found that some important quality indices (weight of single sugar beet root, content of sucrose in root tissues) were higher for beet harvested from digestate treatment compared to standard mineral fertilization (control). The concentration of harmful component (amide nitrogen) in sugar beets grown under conditions of digestate soil application was lower than in the control. It can be concluded that soil application of digestate from processing of sugar beet pulp can be treated as environmentally sound and effective method of its management.