FORMATION OF SOILS

FORMATION OF SOILS

1. 1. CLIMATE

   • TEMPERATURE & RAINFALL INFLUENCE THE RATE AT WHICH PARENT ROCK IS BROKEN DOWN BY WEATHERING
     • HOT CLIMATES = CHEMICAL WEATHERING
     • COLD CLIMATES= FREEZE THAW ACTION

2. 2. VEGETATION

   • WHEN VEGETATION DIES IT DECAYS TO FORM HUMUS WHICH PROVIDES THE SOIL WITH NUTRIENTS
   • DECIDUOUS VEGETATION PROVIDES MORE LEAF FALL THAN CONIFEROUS VEGETATION

3. 3. LIVING ORGANISMS

   • MICRO-ORGANISMS SUCH AS BACTERIA & FUNGI HELP BREAKDOWN THE DEAD PLANT AND ANIMAL LIFE INTO HUMUS.
     • EARTHWORMS DIG THROUGH THE SOIL TO FILTER AIR AND WATER THROUGH THE SOIL.

4. 4. LANDSCAPE

   • UPLAND AREAS = COLD WET
     • SOIL IS WATE LOGGED
     • LESS HUMUS
   • LOWLAND AREAS= DEEP, WELL-DRAINED
     • MORE HUMUS

5. 5. TIME

   • ONE OF THE MOST IMPORTANT FACTORS
     • THE LONGER A ROCK IS EXPOSED TO WEATHERING, THE MORE IT IS BROKEN DOWN
     • IT MAY TAKE UP TO 400 YEARS FOR 1CM OF SOIL TO FORM

6. 6. PARENT MATERIAL

   • TYPE OF ROCK IN AN AREA
     • GRANITE = SLOW TO BREAKDOWN
     • SANDSTONE =EASILY BREAKS DOWN
       • SOIL THAT DEVELOPS FROM LIMESTONE IS MORE FERTILE