The notice of the filing of the petition for inclusion of lands shall state the purpose of the petition, describe the boundaries of the tract of land proposed to be included, and give the names of the petitioners. It shall also notify all persons interested in, or who may be affected by, the proposed inclusion of the land within the district to appear at the office of the board at a time named in the notice for the hearing of the petition and objections thereto and show cause, in writing, if any they have, why the land or any of it should not be included as proposed in the petition. The time to be specified in the notice for the hearing shall be the regular meeting of the board next after the expiration of the time for the publication of the notice.