Agrochemical Conditions of Loamy Haplic Luvisol at Sour Cherry Orchard after 6-Year Treatments by Nitrogen and Potassium Fertilizers

Abstract

In a field experiment in a cherry orchard, the effect of annual application of urea and potassium sulfate on the most important agrochemical properties of the soil in the root zone was evaluated. The soil of the garden is medium-loamy agro-gray with initially favorable parameters: pHKCl 5.8, humus content – 3.58–4.57%. Fertilizers have been applied since 2017 1 time a year in early spring according to the scheme: 1 – control (without fertilizers), 2 – N30K40, 3 – N60K80, 4 – N90K120, 5 – N120K160. Soil samples were taken from soil layers 0–20, 20–40 and 40–60 cm in 2017 (the first year of experience) and in 2022 (after 6 years of fertilization). The annual application of fertilizers for 6 years led to a significant increase (by 1.4–2.2 times) in the availability of exchangeable potassium in the soil layer of 0–20 cm with a constant humus content in the entire root zone. At the same time, an increase in acidity and loss of calcium occurred in the upper layers of the soil under the influence of fertilizers in doses of N60K80 or more. For the period 2018–2022, the highest total yield of Turgenevka cherry trees was noted when applying fertilizers N60K80 and N120K160 (35.5 and 36.5 t/ha, respectively), but this increase was insignificant compared to the control (29.3 t/ha). Thus, an agro-gray medium loamy soil with favorable agrochemical characteristics can ensure the growth and fruiting of cherry trees without the use of fertilizers for 8 years after planting and at the same time the level of soil fertility remains stable.