CONTENT OF MOBILE PHOSPHORUS COMPOUNDS UNDER DIFFERENT METHODS AND RATES OF FERTILIZER APPLICATION DURING THE PERIOD OF THEIR ACTIVE CONSUMPTION BY POTATO PLANTS

Abstract

The article highlights the results of research on the influence of spread and local fertilization methods on the duration of localization, availability and migration of phosphorus compounds in the subsoil zone during the cultivation of seed potatoes. The research was conducted in a field experiment of the Department of Agrochemistry and Quality of Crop Production in the National University of Life and Environmental Sciences of Ukraine on the land use territory of Biotech LTD (Boryspil district, Kyiv region) during 2019-2022. FPK 8-24 was used as a pre-sowing fertilizer in the variant with a spreading method using a self-propelled sprayer Tecnoma Lazer 3000, and potassium chloride was applied using a John Deere 6195M unit and a spreader MVD 1000, followed by their incorporation with a Vaderstad Carrier CR 400 disk to a depth of 10 cm. Localized application was carried out by a unit consisting of a John Deere 8300 and a Peliper RV 3000 cultivator: phosphorus fertilizers (RKD 8-24) were applied with a tape (15 cm depth), and potash fertilizers were applied in a strip (10-12 cm width, 18-20 cm depth) (Bykin & Panchuk, 2021). Nitrogen fertilizers, as a background in all variants, were applied to the pre-sowing soil in the form of UAN-25 + S4, considering the nitrogen applied with FFR 8-24. The use of local fertilization allows to better optimize the nutrition of potato plants. During the period of active phosphorus consumption, a higher content of phosphorus compounds was observed in the variants where fertilizers were applied locally than in the variant where fertilizers were applied in a scattered manner. In particular, even with the application of a reduced rate of fertilizers (P40K90) locally on the background of N150, a higher content of phosphorus and potassium in the soil during the growing season was observed compared to the variant where the full rate of fertilizers (P80K180) was applied on the background of N150 by the scatter method. It was found that fertilizer localization provided a longer period of phosphorus availability in high concentrations. Also, the formation of concentration zones in deeper soil layers was noted, which were less affected by the negative effects of weather conditions and provided potato plants with this element even when the upper soil layers dried out.