Abstract. The purpose of the research was to study the effect of fertilizer rates depending on drainage and weather conditions on the yield and quality of potatoes, their payback with an increase in yield. Methodology and methods of research. The studies were conducted in a two-factor field experiment in 2012–2020, factor A – drainage (drained by closed potter drainage and non-drained soil), factor B – various fertilizer rates (without fertilizers; multi-purpose compost (KMN) 10 t/ha + K90; KMN 10 t/ha + N70K180). The soil of experimental plot of sod-podzolic light loamy are predominant, well-cultivated. Potatoes were cultivated according to the ridge technology developed at VNIIMZ, the predecessor of winter grain crops. According to weather conditions, the years of research are divided into excessively humid, humid and arid. Analyses and observations were carried out according to the generally accepted methods of experimental work, calculations using statistical analysis. Results. The tendencies of changes in the indicators of the water-air regime of the arable layer of soil (moisture, total porosity, porosity of aeration, bulk density) depending on drainage and weather conditions were revealed. The influence of fertilizer rates on drained and non-drained areas, depending on weather conditions, on the content of mineral nitrogen in the soil, yield and its structure, the quality of potato production (content of nitrates, starch in tubers), the use of photosynthetically active solar radiation, payback of fertilizers by an increase in yield has been established. The share of the influence of fertilizers and drainage on the variability of the yield in different weather conditions has been determined. Scientific novelty. The share of the participation of the studied factors in the variability of the potato yield and the rational rates of the use of fertilizers, depending on soil and weather conditions, have been established.
