11.1 Characteristics and challenges of urban soils

Urban soils are unique ecosystems shaped by human activities. They differ from natural soils in their physical, chemical, and biological properties, presenting challenges for plant growth and ecosystem functions.

Construction, pollution, and intensive management practices alter urban soil characteristics. These changes impact water infiltration, nutrient cycling, and biodiversity, requiring specialized approaches to soil management and restoration in urban environments.

Urban Soil Properties and Challenges

Properties of urban soils

Top images from around the web for Properties of urban soils

• 

  Frontiers | Physical, Chemical and Biological Effects on Soil Bacterial Dynamics in Microscale ... View original

  Is this image relevant?

• 

  31.2C: Physical Properties of Soil - Biology LibreTexts View original

  Is this image relevant?

• 

  SOIL - Using constructed soils for green infrastructure – challenges and limitations View original

  Is this image relevant?

• 

  Frontiers | Physical, Chemical and Biological Effects on Soil Bacterial Dynamics in Microscale ... View original

  Is this image relevant?

• 

  31.2C: Physical Properties of Soil - Biology LibreTexts View original

  Is this image relevant?

1 of 3

Top images from around the web for Properties of urban soils

• 

  Frontiers | Physical, Chemical and Biological Effects on Soil Bacterial Dynamics in Microscale ... View original

  Is this image relevant?

• 

  31.2C: Physical Properties of Soil - Biology LibreTexts View original

  Is this image relevant?

• 

  SOIL - Using constructed soils for green infrastructure – challenges and limitations View original

  Is this image relevant?

• 

  Frontiers | Physical, Chemical and Biological Effects on Soil Bacterial Dynamics in Microscale ... View original

  Is this image relevant?

• 

  31.2C: Physical Properties of Soil - Biology LibreTexts View original

  Is this image relevant?

1 of 3

• Physical properties
  • Altered soil structure from human activities disrupts natural layering and aggregation
  • Increased bulk density due to compaction reduces pore space (>1.6 g/cm³)
  • Reduced porosity limits water and air movement through soil profile
  • Variable soil depth ranges from shallow to deep depending on site history
  • Presence of anthropogenic materials like concrete debris and asphalt fragments
• Chemical properties
  • Higher pH levels often exceed 7.0 due to calcareous building materials (limestone)
  • Elevated concentrations of heavy metals accumulate from industrial activities (lead, cadmium)
  • Increased salinity from de-icing salts affects plant growth and soil structure
  • Altered nutrient cycles disrupt natural element transformations and availability
  • Presence of synthetic organic compounds from spills or improper disposal (PCBs)
• Biological properties
  • Reduced soil biodiversity limits ecosystem functions and resilience
  • Altered microbial communities affect nutrient cycling and plant-microbe interactions
  • Lower organic matter content decreases water holding capacity and nutrient retention
  • Disrupted soil food webs impact decomposition and nutrient availability
  • Presence of non-native soil organisms introduces potential invasive species

Human impacts on urban soils

• Construction and development
  • Soil removal and replacement alters natural soil profiles and properties
  • Mixing of soil horizons disrupts natural layering and nutrient distribution
  • Introduction of fill materials changes soil composition and behavior
• Soil sealing
  • Impervious surface coverage prevents water infiltration and gas exchange
  • Reduced water infiltration increases runoff and flood risk
  • Altered soil temperature regimes affect biological activity and plant growth
• Pollution sources
  • Industrial emissions deposit contaminants through air and water pathways
  • Vehicle exhaust contributes to heavy metal accumulation in roadside soils
  • Waste disposal sites leach pollutants into surrounding soil and groundwater
  • Application of de-icing salts increases soil salinity and affects plant growth
• Landscape management practices
  • Intensive irrigation alters soil moisture regimes and can lead to salinization
  • Fertilizer and pesticide use impacts soil chemistry and microbial communities
  • Frequent soil disturbance disrupts soil structure and organic matter accumulation

Challenges of urban soil management

• Soil contamination
  • Sources of contaminants include industrial activities, transportation, and waste disposal
  • Health risks to humans and ecosystems through exposure to toxic substances
  • Remediation techniques and challenges vary based on contaminant type and concentration
  • Legal and regulatory considerations complicate land use and redevelopment
• Soil compaction
  • Causes of urban soil compaction include heavy machinery and foot traffic
  • Effects on root growth and plant health limit vegetation establishment and growth
  • Impacts on water infiltration and runoff increase flood risk and reduce groundwater recharge
  • Mitigation strategies and limitations include soil amendments and decompaction techniques
• Monitoring and assessment
  • Soil testing methods for urban environments require specialized protocols
  • Challenges in representative sampling due to soil heterogeneity and contamination
  • Interpretation of results in complex urban matrices demands expertise and caution

Urban soils and ecosystem function

• Plant growth limitations
  • Restricted root development due to compaction and physical barriers
  • Nutrient deficiencies or imbalances affect plant health and productivity
  • Water stress due to altered hydrology impacts plant survival and growth
  • Heat stress from urban heat island effect increases plant transpiration and water demand
• Ecosystem services affected
  • Carbon sequestration potential reduced due to lower organic matter content
  • Water filtration and purification capacity diminished by soil sealing and contamination
  • Flood mitigation capacity decreased due to reduced infiltration and storage
  • Urban biodiversity support limited by altered soil habitats and reduced connectivity
• Urban forestry challenges
  • Tree longevity in urban settings shortened by stress factors and limited soil volume
  • Species selection for urban conditions requires consideration of pollution and drought tolerance
  • Management of street trees and urban parks faces unique soil-related obstacles
• Green infrastructure performance
  • Effectiveness of rain gardens and bioswales depends on soil infiltration capacity
  • Rooftop garden substrate considerations include weight limitations and drainage
  • Urban agriculture soil management addresses contamination and nutrient cycling challenges