Plum is one of the main fruit crops in the southern regions. Its fruits are the most valuable food, as they contain sugars, vitamins, biologically active elements, pectins, minerals, as well as macro- and microelements necessary for humans [5].

The most important link in the quality assurance system is mineral nutrition [1].

Trees in the orchard, growing for several years in the same place, cause depletion of the soil nutrients. In this regard, obtaining stable high yields of commercial fruits in orchards is possible only with the use of scientifically justified doses and combinations of mineral and organic fertilizers, calculated taking into account the full coverage of the needs of all trees in nutrition elements.

Depending on the variety and growing conditions the plum fruit contains 10–30 % solids, 10–20 sugars, 0.4–2.7 % of acids, 0.3–2.1 mg/100 g of pectin, 15–18 mg/100 g of vitamin C, up to 80 mg/100 g of P-active substances, up to 350 mg/100 g of anthocyanins etc. [3–4].

The issues of optimizing the mineral nutrition of fruit trees in gardens in the conditions of North Ossetia -Alania have not been sufficiently studied. To develop a fertilizer system on leached black-earth (chernozem) in 2020, the effectiveness of various doses and combinations of mineral and organic fertilizers in an intensive plum orchard was studied. The garden was laid out in April 2015 based on a 4x5 m pattern. The object of the research was the Green Gage plum.

The layout of the trees is 4x5 m. There are 10 trees of each variety in the plot, replicated four times. The experiment design is shown in tables 1 and 2.

The soil is leached black-earth (chernozem) with a humus horizon capacity of 40–50 cm. The main indicator characterizing the state of soils is the content of humus, nitrate-nitrogen, and mobile phosphorus [6].

4.6–6.1% of humus is contained in the arable layer of the studied soil, there is a high content of total nitrogen (0.25–0.46%), phosphorus (0.2–0.3), potassium (1.7–2.4%). The climate of the forest-steppe zone of the plum orchard is moderately warm, with sufficient humidification. An average of 680 mm of precipitation falls per year. The sum of positive temperatures is 3050–3250 °C [2].