An agricultural machine comprising a rotary drum, a lateral flange and at least one bearing assembly for connecting the drum to the lateral flange, the bearing assembly comprising: - a shaft end defining a geometrical shaft axis and provided with a convex annular slide bearing face around the shaft axis, the convex annular slide bearing face having a constant radius of curvature and a centre of curvature, the convex annular slide bearing face being located between two parallel geometrical transverse planes (P21, P22) perpendicular to the shaft axis, the centre of curvature being located on the shaft axis between the two transverse planes (P21, P22) at a distance of each of the transverse planes (P21, P22) smaller than the radius of curvature; characterised in that the bearing assembly further comprises: - a roller bearing comprising an outer race ring assembly, an inner race ring assembly and two annular rows (18, 20) of rolling bodies which roll between associated annular raceways (24, 26, 28, 30) formed on the inner and outer race ring assemblies (16, 14) to define a rotation axis of the roller bearing; wherein the inner race ring assembly includes: - a cavity with a concave annular slide bearing face having a centre of curvature located on the rotation axis and a constant radius of curvature equal to or larger than the radius of curvature of the convex annular slide bearing face of the shaft end, and - a cylindrical insertion hole having a diameter which is smaller than twice the radius of curvature of the concave annular slide bearing face and provided with an insertion slot formed on two diametrically opposite portions of the cylindrical insertion hole and having a width measured in a transverse plane perpendicular to the rotation axis and a length measured in the transverse plane, the width being larger than a distance between the two parallel geometrical planes (P21, P22), the length being larger than twice the radius of curvature of the convex annular slide bearing face, the insertion slot being shaped to allow the insertion of the shaft end into the cavity, and wherein the shaft end has a protruding portion extending outside the space delimited by the two transverse planes (P21, P22) and entirely located within a spherical envelope, the spherical envelope having a centre which is the centre of curvature of the convex annular slide bearing face and a diameter smaller than the diameter of the cylindrical insertion hole. - a shaft end defining a geometrical shaft axis and provided with a convex annular slide bearing face around the shaft axis, the convex annular slide bearing face having a constant radius of curvature and a centre of curvature, the convex annular slide bearing face being located between two parallel geometrical transverse planes (P21, P22) perpendicular to the shaft axis, the centre of curvature being located on the shaft axis between the two transverse planes (P21, P22) at a distance of each of the transverse planes (P21, P22) smaller than the radius of curvature; characterised in that the bearing assembly further comprises: - a roller bearing comprising an outer race ring assembly, an inner race ring assembly and two annular rows (18, 20) of rolling bodies which roll between associated annular raceways (24, 26, 28, 30) formed on the inner and outer race ring assemblies (16, 14) to define a rotation axis of the roller bearing; wherein the inner race ring assembly includes: - a cavity with a concave annular slide bearing face having a centre of curvature located on the rotation axis and a constant radius of curvature equal to or larger than the radius of curvature of the convex annular slide bearing face of the shaft end, and - a cylindrical insertion hole having a diameter which is smaller than twice the radius of curvature of the concave annular slide bearing face and provided with an insertion slot formed on two diametrically opposite portions of the cylindrical insertion hole and having a width measured in a transverse plane perpendicular to the rotation axis and a length measured in the transverse plane, the width being larger than a distance between the two parallel geometrical planes (P21, P22), the length being larger than twice the radius of curvature of the convex annular slide bearing face, the insertion slot being shaped to allow the insertion of the shaft end into the cavity,