GROWTH AND DEVELOPMENT OF POTATO PLANTS UNDER DIFFERENT METHODS AND NORMS OF FERTILIZER APPLICATION

Abstract

Potatoes are one of the main food products of people. It is used to obtain starch, glucose, hydrol, alcohol, and other substances. The growing need for this raw material requires constant improvement of potato growing technologies to obtain a high level of harvest with good indicators of tuber quality. Scientific research was carried out in the field experiment of the department of agrochemistry and the quality of plant products named after O. I. Dushechkina of the National Institute of Science and Technology of Ukraine on the land use territory of Biotech LTD LLC (Boryspil district, Kyiv region). The soil of the experimental site is a dark gray, golden, coarsegrained, light loamy loam in the loess. The early ripening variety Tiras was chosen for the research. The scheme of the field experiment provided various methods and rates of application of phosphorus and potash fertilizers. As a background in all variants of the experiment, nitrogen fertilizer was applied to the pre-sowing soil treatment, with the rate of N100 on the soil surface, followed by its cultivation. The rest of the nitrogen in the norm of N35 in the form of UAN-25 was applied before the formation of ridges with their subsequent formation by a ridge former, and N15 in the form of calcium nitrate as a top dressing. Liquid complex fertilizer (APP) 8–24 was applied as a pre-sowing fertilizer in a spreading method using a Tecnoma Lazer 3000 self-propelled sprayer, and potassium chloride was applied using a John Deere 6195M unit and an MVD 1000 spreader, followed by spreading with a Vaderstad Carrier CR 400 disk cultivator to a depth of 10-12 cm. Local application of fertilizers was carried out with a John Deere 8300 unit and a Peliper RV 3000 cultivator. Phosphorous fertilizers were distributed in the soil with a tape (15 cm deep), and potassium fertilizers with a strip (10–12 cm wide, 18–20 cm deep). The local introduction of P60K135 on the background of N150 provided the maximum height of potato plants (77.8 cm) under the experimental conditions. At the same time, a similar method of application with an increase in the rate of phosphorus and potassium fertilizers to the level of P80K180 against the background of N150 resulted in a lower plant height (71.3 cm). The greatest influence on the formation of the vegetative part of plants was exerted by the local application of phosphorus and potassium fertilizers at the rate of P60K135 against the background of N150. It provided the largest indicator of the mass of above-ground (38.0 t/ha) and underground part of plants (28.7 t/ha), which is 2.6 t/ha more than the option with a similar method of applying the full rate of P80K180 on the background of N150. The largest area of the leaves before the “green berry” phase was formed in the variant with local application of P80K180 against the background of N150 and reached 56873 m2/ha with a leaf index of 5.69. Scattered application of the same rate of fertilizers caused this indicator to be obtained at the level of 48191 m2/ha, which is 8682 m2/ha less than the abovementioned option. During this period, the largest mass of tubers under one bush was formed when applying P60K135 locally on the background of N150 – 458 g. The increase of the local norm to P80K180 on the background of N150 led to the formation of a slightly smaller mass of tubers – 408 g, which is 12.1 % less than the above-mentioned option. Therefore, the local application of phosphorus and potassium fertilizers can condition the better growth and development of potato plants of the Tiras variety in the main phases and tubers in particular.