The effect of mineral fertilizers on the seasonal dynamics of exchangeable potassium in the orchard soil and the potassium status of sour cherry trees

Russian Research Institute of Fruit Crop Breeding (VNIISPK), Zhilina, Orel district, Orel region, Russian Federation

^* Corresponding author: roeva@vniispk.ru

Abstract

The study was conducted to assess the impact of mineral fertilizers applied to the soil on the potassium level in the components of the “soil-plant” system of the sour cherry orchard. The experiment was conducted in the forest-steppe zone of the Central Russian Upland (Orel region) on loamy Haplic Luvisol during 2018-2020. The seasonal dynamics of exchangeable potassiumin the soil, the potassium status and productivity of sour cherry trees cv. ‘Turgenevka’ on the rootstock V-2-180 were studied in the orchard of 2015 planting. Fertilizers in the form of (NH₂)₂CO and K₂SO₄ were applied annually in early spring in doses of N30K40, N60K80, N90K120 and N120K160. It was found that a significant decrease in the level of potassium in the soil occurred during the period of intensive growth and crop formation, or after heavy precipitation. The use of fertilizers increased the content of exchangeable potassium in the soil (by 1.2-2.2 times), while the features of the potassium dynamics observed in unfertilized plots were preserved. Fertilizers contributed to the annual improvement of the potassium status of the leaves (by 0.05-0.24 % DW). The positive effect of fertilizers on the potassium content in fruits and the productivity of trees was manifested only in a year with prolonged intense precipitation (2020). The potassium content in fruits was 1.12-1.16 times higher than the control when applying N30K40, N60K80 and N90K120. A significant increase of tree productivity was found when applying N60K80 and N120K160 (by 54 and 69%, respectively).