Soils

Soils

1. Structure

   • granular - rounded aggregates separated from each other. Surface soils (A horizon). high in organic matter
   • Platy - thin horizontal plates in surface soil layers. often in herited by parent materials
   • Angular block y- nearly square or angular blocks from 1 - 10cm
   • Prismatic - vertical orientated aggregates in subsurface horizons

2. Aggregates - soil particles stuck togeter

   • electrical charges on particle surfaces
   • soil organic matter
   • clay skins
   • polysaccaride gums and other cements (Fe and Al oxides)

3. Soil PH

   • Measure Acidity and ALkalinity
   • Affects all Chemical and Biological Processes
   • Affects form availability, tranformation nutrients and heavy metals thus environmental pollution potential and soil fertility
   • Affects microbial acitivity, weathering processes and soil formation processes
   • Plant growth
     • Acidity problems Alminum toxicity and Ca defficency
     • tracce element defficency
   • Nutrient availability for plants and animals. Macronutrients netural and Micronutrients at low PH
   • High H+ ions (low PH) ehances mineral weathering
   • Microbial activity
     • Bacteria Higher Ph
     • fungi - wider PH range

4. surface charge

   • most active - Organic Matter and clays due to surface charge and large specific surface