Root Environment

Root Environment

1. Soil

   • Soils vary by: pH Stone,Sand,Loam content Drainage Depth of layers Fertility Organic content Contaminents  
   • Function
     • Physical Support
     • Holds air,water,nutirents
     • home for organisms
   • Constituents
     • Minerals 50-60%
       • Sand
       • Clay
       • Silt
     • Water 5-40%
     • Air 5-30%
     • OM 1-5% (unless peaty)
     • living organisms
   • Properties
     • pH
     • Texture
       • Relative proportions sand,silt clay Determined by feel and touch or soil analysis
       • Sandy
         • Free draining
         • Water drains quickly
         • Lgest mineral particles
         • Warms & cools quickly
         • Doesn't hold nutrients
         • No swelling or shrinking
         • Felels gritty when wet
         • no electic charge
       • Silt
         • Can be hard to drain
         • Hold mod water
         • med sized particles
         • warms/cools >clay<sand
         • holds limited nutrients
         • Limited swelling and shrinking
         • Makes v.fertile soil
         • No electrical charge
         • Silky ahnd soapy when wet
       • Clay
         • Readily waterlogged
         • Heavy when wet
         • Smallest mineral particles
         • Long time to warm/cool
         • Holds onto nutrients
         • swells and shrinks
         • -ve charge
         • Good water retention
       • Loam
         • Any mixture of sand silt and clay is a loam
     • Minerals
       • Firm Anchorage
       • Determins which plants grow
       • Provides Nutirents
       • Affect workability
   • Profile
     • Top Soil Horizon
       • Agregates = crumbs
       • Most Fertile Part
       • Most soil organisms
       • Most OM
       • Darkest
       • Most Roots
       • Depth varied 30-60cm best
     • Subsoil Horizon
       • Lage Agrregates
       • Some soil organisms
       • Little or no OM
       • Lighter colour
       • Onlyl roots of treens and shubs
       • V Varied depth
     • Parent Rock
     • Organic Horizon
   • Soil Water
     • Typesl
       • Gravitatonal
       • Capillary
       • Hygroscopic
     • Determines workability
       • Clay heavy
         • Not always workable
       • Sandy light
         • cultivate most of year
     • Definitions
       • Saturation
       • Field Capacity
       • Permanent Wilting Point
       • Available water content = FC-PWP
       • Soil Moisture Deficit
   • Soil Air
     • Function
       • Respiration of roots
       • Repiration of living organisms
     • Availability
       • Surface must be permeable not compacted or capped
       • Balanced with water
       • more co2
   • Soil OM
     • Dead and decaying animal and plant life. Once fully decomposed = Humus