Notwithstanding the provisions of Sections 29400, 29401, and 29403, the local protection program for that portion of the secondary management area west of Shiloh Road and south of State Highway Route 12 may not prohibit construction of reasonable improvements (including construction of individual single-family dwellings) related to the long-term continuation of existing agricultural uses; nor shall the local protection program limit or prohibit divisions of agricultural land within or adjacent to this portion of the secondary management area if such divisions of land do not affect long-term continuation of compatible agricultural uses within, or adjacent to, the marsh.