The effect of long-term cultivation practices including fertilization through drip irrigation (fertigation) on some parameters of soil fertility using logical function was taken under consideration in this study. Representative soil samples were collected in 2021 from an area planted with avocado trees in 1997. Results showed that the change in soil fertility of the tested area at parallel and perpendicular to drip irrigation lines were 109% and 110% respectively relative to control treatment (non-fertigated soil) equal 100%. Based on the logical function, the total indices of the tested soil parameters related to soil fertility were 34.0, 36.5, 37.8 with soil fertility classes of L (Low), L and M (Medium) for control, at 100 and 200 cm away from tree trunk in parallel to drip irrigation line respectively. Soil fertility classes at parallel and perpendicular to drip irrigation line were L and L respectively. It could be concluded that the soil fertility class of the investigated soil changed as affected by the long-term of drip fertigation by about 7, 11 and 12, 10 % relative to the non-fertigated soil at 100 and 200 cm away from tree trunk in parallel and perpendicular to drip irrigation lines respectively.