The influence of nitric and potash fertilizers on the reserves of nitrogen and potassium in the soil of cherry orchard and its trees efficiency

The impact of fertilization with urea and potassium sulfate on supply of alkali-hydrolysable nitrogen and exchangeable potassium in soil of sour cherry orchard was studied in the field experiment during 2017-2019 vegetation seasons. The experiment was conducted in soil and climatic conditions of forest-steppe zone at the Central Russian Upland (Orel Region). The sour cherry trees of ‘Turgenevka’ cultivar were planted in 2015 at 5x3 m apart on the loamy HaplicLuvisol with pHKCl 5.8, level of humus 4.8 %, high content of phosphorus available forms - 383 mg/kg.. The experiments’ variants: 1. Control (without fertilizers); 2. N30K40; 3. N60K80; 4. N90K120; 5. N120K160. Soil fertilizers were applied once a year in early spring. Soil samples were collected from the layers 0-20, 20-40 cm annually in October. The content of alkali-hydrolysable nitrogen at the depth 20-40 cm rose by 10 % after three years of fertilization with urea in N30 and N60 doses. The supply of exchangeable potassium in 0-20 cm soil layer significantly increased in 2019 compared to the level of 2017 at all treatments with potassium sulfate. On average during three years of carrying out the researches the content of exchange potassium in the soil which is steadily exceeding control was provided by doses of Kc 80 and 120 kg / hectare a.i. The greatest productivity of ‘Turgenevka’ sour cherry trees (on 69 % higher than the control) was observed at N120K160 treatment at fourth year of the experiment.