The aim of the present research was to estimate the long-term effect of soil management in orchards on selected physicochemical properties of humus substances isolated from Luvisols. It involved determining basic parameters of humic acids extracted from soils. Samples from topsoil were collected from apple tree orchards and arable soils in the Chełmińskie and the Krajeńskie Lake Districts. The humus substances of orchard soils showed lower condensation of aromatic rings in the molecules of humic acids, which, in turn, suggests their lower chemical maturity. Similarly, the long-term soil management in orchards decreased the resistance of humic substances to chemical oxidation. The humic acids extracted from orchard soils demonstrated a higher content of aliphatic structures.