Soils

Soils

1. Porosity /pore space

   • space between solids
   • holds: water, dissolved nutrient, soil air
   • affects water retension and drainage areation
   • sand has more macropores however clay has greater porosity
   • Macropores
     • low water retension
     • enhance areation
     • high hydraulic conductivity (easily conduct water)

2. soil water

   • rainfall - adding water to surface soil
   • inflitration - moves into soil pores
   • drainage - water starts flowing downwards
   • water drains out of the root zone but some retained by soil through particle attraction to water
   • saturated flow
     • macro and micro pores filled with water
     • lower soil horizons during and immediately after heavy rainfall