The nutritive regime for leached black soil in an apple orchard depending on fertilizers

Abstract

This article presents the results of studying the dynamics of the nutritive regime for leached black soil during the vegetation period of apple trees depending on the dosage and application times of compound fertilizers, as well as combinations of organic and mineral fertilizers. We detected a positive influence of fertilizers on the accumulation of liable forms of nitrogen, phosphorus, and potassium in the soil of the fruit orchard. The highest average content of ammonia absorbed during vegetation was observed in section N180P180K180 – 40.6 mg/kg, which was 10.4 mg/kg higher than in the unfertilized ref-erence section. The content of nitrates in the reference section was 8.9 mg/kg of the soil. The application of N60P60K60 increased their content by 2.3 mg/kg (25.8%), N90P90K90 - by 3.1 mg/kg (34.8%), N120P120K120 - by 4.8 mg/kg (53.9%). The application of mineral fertilizers at various rates had a significant impact on the content of liable phosphorus in the 0-40 cm layer of soil: its average content per vegetation period was 101.8 mg/kg of the soil for section N60P60K60 and 129,1 mg/kg for section N150P150K150. The content dynamics for exchangeable potassium in the fruit orchard soil was at the maximum at the beginning of the vegetation period and the minimum during fruit formation. Later on, the content increased during the harvesting stage but it was lower than the original level. The highest average content of exchange-able potassium per vegetation period was observed in section N150P150K150 – 184 mg/kg, which was 44 mg/kg higher than in the reference section. Out of the two sections treated with manure, the Manure 20 t/ha+N30P70 (with NPK reaching up to 120 kg/ha) section was deemed more efficient. The content of exchangeable potassium in it exceeded the reference section by 41 mg/kg.