论文部分内容阅读
Impacts on physical soil properties occur often in urban areas.They are perhaps more frequent then by pollution.Today there are many measures to stop pollution.But nothing is done to stop physical impacts on soils.The effects on goods and life quality of urban population will be perhaps much larger than from pollution.Change of physical properties of soils concern the soil texture,which shift to increased occurrence of more stony and sandy particles.Soils are deep disturbed by filling in of soils.By transport and levelling soils are deep compacted.By sealing permeability and in part aeration properties of soils are lost.On the other hand high carbonate content and supply of fresh plant material from lawn cutting improves living conditions of earth worms with time and by this occurrence of large and permeable pores.Functions wanted from soils in urban areas are fast storm water uptake and high short time water storage capacity to prevent floods,high water storage capacity for plants to develop a big green volume with all its benefits,and to supply and heat storage to mitigate the climate.Particular to the reduction of soils in urban areas it will be important to use the left soils in an optimal way.That means a big volume by deep loose soils should be available which can be rooted and used for water infiltration.For the use of soil underneath sealed areas air diffusion would be of importance.Some soils are from textures of low mechanical stability.They will be easily dispersed and eroded.Particular this will happen in soils of low water storage capacity due to their flatness.This is particular found on landfills and contaminated land which are covered with impervious sealing layers and flat soil layers.Which investigation methods are available for soil physical properties investigation? Already often water infiltration measurements are done.But the water infiltration methods used are often not suitable.Bulk density is already seldom investigated.Far away to belong to the standard investigation methods are determination of water permeability,gravel,sand and organic matter content.Air permeability and diffusion,and soil plasticity and soil shear resistance measurements are not performed.Some of these methods can be used as fast field methods.We have to conclude that there is a big field to be developed by urban soil science.