Thompson pollution and the re-cycling of matter. Physical planners have, of course, long been concerned with the loss of open space in and around cities. But too often they over-played the "calamitous loss of irreplaceable prime agricultural land" which in some not too clear way was held to threaten our very existence. Their anguish in a time of farm surpluses did not transfer well to their critics.9 Tax abatement for near-in farms never did elicit much support, nor would it have prevented many rural to urban land con-versions. Care would have to be taken that property tax reductions did not simply subsidize and encourage land speculation. The case for urban open space has always seemed to rest primarily on recre-ational use and secondarily on its use to delineate boundaries more sharply to strengthen community identity and build civic responsi-bility. An ironic turn of fate may bring forth a new variation on the old theme of agricultural land as urban open space. Experimental design is underway in at least one urban area (Muskegon, Michigan) for dumping liquid household effluent on porous soils (sand dunes) over a period long enough to enrich these soils to good agri-cultural quality. Waste disposal becomes the re-cycling of matter. Natural ecological imperatives could come to dictate popula-tion densities and urban land-use patterns. Given then the speed of transportation and the maximum acceptable commuting time (one hour?), the urban area may come to be defined "from the ground-up." The current direction of causation would then be reversed: city size would not determine population density and land-use patterns but rather land-use patterns and population density, as bounded by 27 May 1971

DOI link for Thompson pollution and the re-cycling of matter. Physical planners have, of course, long been concerned with the loss of open space in and around cities. But too often they over-played the "calamitous loss of irreplaceable prime agricultural land" which in some not too clear way was held to threaten our very existence. Their anguish in a time of farm surpluses did not transfer well to their critics.9 Tax abatement for near-in farms never did elicit much support, nor would it have prevented many rural to urban land con-versions. Care would have to be taken that property tax reductions did not simply subsidize and encourage land speculation. The case for urban open space has always seemed to rest primarily on recre-ational use and secondarily on its use to delineate boundaries more sharply to strengthen community identity and build civic responsi-bility. An ironic turn of fate may bring forth a new variation on the old theme of agricultural land as urban open space. Experimental design is underway in at least one urban area (Muskegon, Michigan) for dumping liquid household effluent on porous soils (sand dunes) over a period long enough to enrich these soils to good agri-cultural quality. Waste disposal becomes the re-cycling of matter. Natural ecological imperatives could come to dictate popula-tion densities and urban land-use patterns. Given then the speed of transportation and the maximum acceptable commuting time (one hour?), the urban area may come to be defined "from the ground-up." The current direction of causation would then be reversed: city size would not determine population density and land-use patterns but rather land-use patterns and population density, as bounded by 27 May 1971

Thompson pollution and the re-cycling of matter. Physical planners have, of course, long been concerned with the loss of open space in and around cities. But too often they over-played the "calamitous loss of irreplaceable prime agricultural land" which in some not too clear way was held to threaten our very existence. Their anguish in a time of farm surpluses did not transfer well to their critics.9 Tax abatement for near-in farms never did elicit much support, nor would it have prevented many rural to urban land con-versions. Care would have to be taken that property tax reductions did not simply subsidize and encourage land speculation. The case for urban open space has always seemed to rest primarily on recre-ational use and secondarily on its use to delineate boundaries more sharply to strengthen community identity and build civic responsi-bility. An ironic turn of fate may bring forth a new variation on the old theme of agricultural land as urban open space. Experimental design is underway in at least one urban area (Muskegon, Michigan) for dumping liquid household effluent on porous soils (sand dunes) over a period long enough to enrich these soils to good agri-cultural quality. Waste disposal becomes the re-cycling of matter. Natural ecological imperatives could come to dictate popula-tion densities and urban land-use patterns. Given then the speed of transportation and the maximum acceptable commuting time (one hour?), the urban area may come to be defined "from the ground-up." The current direction of causation would then be reversed: city size would not determine population density and land-use patterns but rather land-use patterns and population density, as bounded by 27 May 1971