At the time of the hearing, the Department of Agriculture shall receive any competent and relevant evidence which may be produced by any person interested in the organization of such district in support of or against the petition. If the department finds that the boundaries proposed by the petitioners should be changed, it shall change the same and fix the boundaries where the same, in the judgment of the department, should be fixed with a view to doing justice and equity to all persons; PROVIDED, that if the department deems it proper to include in the district any territory not included in the boundaries proposed by the petitioners, it shall first cause notice of its intention to do so to be mailed to each owner of land within the territory proposed to be included. Such notice shall describe the territory so proposed to be included in the proposed district and fix a time and place, not less than one week nor more than three weeks from the date of mailing thereof, when all persons interested may appear and be heard.