The paper presents the results of studies on the study of different doses of potash fertilizers in combination with phosphate fertilizers, both with a separate application and in combination with the biological product Humimax, when cultivating narrow-leaved lupine for green mass, in a field experiment on soddy-podzolic sandy soil (with a pollution density of 20 and more than Ku/km2). The effectiveness of the influence of doses of potash fertilizers and the biopreparation Humimax on the yield, accumulation of 137Cs and the nutritional value of the green mass of the narrow-leaved lupine was studied. It has been established that the use of the Humimax biopreparation provides an increase in the yield of the green mass of lupin up to 69%. The use of the biological product on all backgrounds of fertilization provides an increase in the content of crude protein in the green mass of lupine. Consistently increasing doses of potassium in combination with P45, both when used alone and in combination with a biological product, reduced the specific activity of 137Cs by more than 2.5 times. To reduce the accumulation of 137Cs in the green mass of lupine below the permissible level, the doses of mineral fertilizers should not be lower thanP45K150.

The results of studies on the effect of different doses of mineral fertilizers and the biopreparation Humimax on the productivity and quality of oat grain when cultivated on soddy-podzolic sandy soil with a pollution density of 20 or more Ci/km2, and on the transfer of radionuclides into oat grain are presented. It has been established that the use of the biopreparation Humimax provides an increase in the yield of oat grain by 23%. Consistently increasing doses of potassium in the composition of NPK, both with a separate application and in combination with a biological product, reduced the specific activity of 137Cs in oat grain by more than 3 times. The use of the drug Humimax on all backgrounds of fertilization provides an increase in the content of crude protein in the grain.