FIELD: agriculture.SUBSTANCE: invention refers to agriculture. Composition of the soil conditioner contains diatomite and succinic acid with the following component ratio, mass%: diatomite 85–90, succinic acid 15–10. For the preparation of soil conditioner composition, preliminarily heat the diatomite crumb at a temperature of 700–900 °C. After that, a solution of succinic acid is applied to the crumb. Treated granules are then mixed for 15–20 minutes in a granulator at a speed of 30 to 40 Hz when the bowl is tilted from 40 to 50° until the disappearance of lumps and wet areas. After that, the granules are dried at a temperature of 15 to 25 °C, spreading them in a thin layer on a flat, dry and clean surface.EFFECT: invention makes it possible to improve the condition of soils.2 cl, 3 tbl, 2 ex