The provisions of this regulation may not be construed to require a buffer or a vegetated filter strip for an agricultural drainage ditch, if the adjacent agricultural land has in place a soil conservation and water quality plan as required in COMAR 27.01.06.03. Agriculture is authorized in the buffer, if, as a minimum agricultural best management practice, a vegetated filter strip of at least 25 feet, measured landward from the mean high water line of tidal [waters or tributary streams or from the edge of tidal wetlands] waters, from the landward boundary of a tidal wetland, or from the edge of each bank of a tributary stream, whichever is farther inland, is established, and if: The filter strip is composed of trees, shrubs, grass, or mixed vegetation and is managed as to provide water quality benefits and habitat protection consistent with the policies stated in Regulation .01 of this chapter. Noxious weeds, including Johnson grass, Canada thistle, and other invasive plants, such as multiflora rose, which occur in the filter strip, may be controlled by authorized means; The filter strip is expanded by a distance of 4 feet for every 1 percent of slope, for slopes greater than 6 percent; The filter strip is maintained until the landowner is implementing, under a soil conservation and water quality plan, a program of agricultural best management practices for the specific purposes of improving water quality and protecting wildlife and plant habitats, and if the portion of the soil conservation and water quality plan being implemented achieves the water quality and habitat protection objectives of the filter strip; The feeding or watering of livestock does not occur within 50 feet measured landward from the mean high water line of tidal waters, from the landward boundary of a tidal wetland, or from the edge of each bank of a tributary stream, whichever is farther inland; Clearing of existing natural vegetation in the buffer is prohibited; and Agricultural activities, including the grazing of livestock, do not disturb stream banks, tidal shorelines, or other habitat protection areas covered, as applicable, in this chapter.