Pursuant to the authority of Section 9-220, Tax-Property Article, Annotated Code of Maryland, there is hereby established a tax credit of one hundred percent (100%) of the County real property tax imposed on any conservation land, as defined therein, provided all the requirements of this Section are met. The conservation land must be used: To assist in the preservation of a natural area; For the environmental education of the public; Generally to promote conservation; or For the maintenance of: A natural area for public use; or A sanctuary for wildlife. Application and proof of eligibility for exemption shall be filed with the Office of Law no later than October 1 of the tax year for which exemption is sought.