A description of urban soils and their desired characteristics

摘要: Human activity in urbanization creates urban soils that have characteristics unlike those of their natural counter- parts. Compaction, restriction water movement and aera- tion, presence anthropeic materials, limited or confined rooting space interrupted nutrient cycling are major prob- lems, among several others, commonly encountered when planting maintaining vegetation. These explain- ed to aid recognition the field. Desired soil given possible solutions briefly discussed. Most people involved with vegetation environment soon discover material excavated by shovel backhoe does not appearance properties very similar found surrounding country, what they might learned from a textbook on fundamentals science. Further, presents them problems plant sur- vival growth (2). The purpose this paper is describe these dissimilarities implica- tions for management, finally, discuss desired soils. This should presented ur- ban suggest prac- tical nature, though detailed discussion latter beyond scope paper. Definition soil. Urban created process therefore cannot be separated geographic bounds process. Highly distrub- land associated material, such as strip-mine spoil banks, do occur outside banized areas some areas, but considered here. activity, modification soilscape, predominant active agent. contrast agents wind, water, ice, gravity heat placement parent within which resultant soil-forming processes environment. Urbanization also contributes unique amendments contaminants create special problems. Bockheim (3) gives an appropriate useful definition soil: A having non-agricultural, manmade surface layer more than 50 cm thick, has been produced mix- ing, filling, contamination suburban areas. inference at least partially disturbed portion profile perhaps entire may consist fill, human primary agent disturbance. mixing, filling its counterpart properties. Mixing occurs scraped away, stockpiled respread, it transported another location spread topsoil. Exposure subsoil cutting down truncates eroded nature. Filling refers dumping spreading over existing raise higher level, backfill ditches foundation walls construct berms. Contamination arises deposition, materials found, concentrations greater solids glass, wood metal, asphalt, masonry, plastic. Atmos- pheric-deposited included. Gases landfill pipeline leaks must well.