Changes of the agrochemical soil characteristics in the stone fruit orchard with the permanent application of nitrogen and potash fertilizers

The purpose of the research was to evaluate the changes in the agrochemical properties of the sour cherry orchard soil after the permanent soil fertilization with urea and potassium sulfate. The field experiment was conducted during 2017-2021 in the soil and climatic conditions of the Central Russian Upland (Oryol region). ‘Turgenevka’ sour cherry trees grafted on the rootstock V-2-180 were planted in 2015 at a distance of 5x3 m. The soil of the orchard is loamy Haplic Luvisol with the following parameters: pHKCl - 5.8, organic matter content - 2.8%, available phosphorus - 383 mg/kg, exchange potassium -120 mg/kg, alkali-hydrolysable nitrogen - 108 mg/kg. Experimental scheme: 1. Control (no fertilizers); 2. N30К40; 3. N60К80; 4. N90K120; 5. N120K160. Fertilizers were applied once a year in early spring. The annual use of fertilizers in N90K120 dose or more contributed to an increase in the reserves of mobile phosphorus, exchange potassium, and alkali-hydrolysable nitrogen in the orchard soil, but did not have a stable effect on the tree productivity. At the same time, there was an increase of soil acidity and loss of exchange calcium under the influence of fertilizers, which indicates the beginning of degradation processes