Influence of nitrogen and potash fertilizers on the accumulation of <sup>137</sup>Cs by perennial legume-cereal and cereal grasses on peat soils
It has been established that on peat shallow soil, the use of P<sub>60</sub>K<sub>240</sub> (K<sub>180</sub> for the first grass cutting and K<sub>60</sub> for the second grass cutting) under perennial legume-cereal grasses reduces the <sup>137</sup>Cs content in hay by 2.2-3.0 times. The use of nitrogen fertilizers in total rates from 30 to 90 kg/ha against the background of P<sub>90</sub>K<sub>180</sub> reduces the concentration of <sup>137</sup>Cs in the hay of the first cut by an average of 1.7-2.0 times, in the hay of the second cut by 1.5-1.9 times. On peaty-gley soil, phosphorus and potash fertilizers in rates of P<sub>90</sub>K<sub>90</sub> reduce the transfer of <sup>137</sup>Cs into perennial grasses of the first cut by 27-28 %. When K<sub>120</sub> is introduced for the first cut, a decrease in <sup>137</sup>Cs input from the soil into plants is observed. Top dressing of grasses of the second cut with potassium at a dose of 30 kg/ha against the background of P<sub>90</sub>K<sub>90</sub> provides a 50 % decrease in the coefficient of radionuclide conversion into hay. The introduction of cereal grasses N<sub>60</sub> and N<sub>80 </sub>for the first cut does not significantly increase the <sup>137</sup>Cs intake into plants. The second nitrogen fertilization of grasses leads to a slight increase in the accumulation of <sup>137</sup>Cs in the hay of the grasses of the second cut. The intake of <sup>137</sup>Cs in hay at increased doses of nitrogen fertilizers (N<sub>120</sub><sub>-</sub><sub>140</sub>) decreases against a high background of potassium use.