Proposed site design shall be compatible with preservation of environmentally sensitive areas. In the R-A Zoning District, the site of new residential development within the tract shall, where possible, be restricted to that contiguous area of the tract with the least agricultural capability as determined by conditions of slope and soil standards. In addition, the site of the farm tract shall be located, where possible, to preserve the maximum amount of prime agricultural soils so as to preserve the agricultural use potential of the farm tract and place new lots in closer proximity to adjacent tracts zoned for higher density uses than to those zoned for agricultural preservation.