WHAT IS SOIL?Tropical and Temperate Soils

Dr. S. Paramananthan

Param Agricultural Soil Surveys (M) Sdn. Bhd.

WHAT IS SOIL?Soil occurs on the surface of the landOccurs on level or hilly and steeplandIt can be shallow (100 cm)It has many colours red, yellowish brown, brown, gray, white blue or blackIt can be made up of organic or mineralIt can be poorly or well drainedIt can be sandy, clayey, or mixture of both

DefinitionNatural body occurring on earths surfaceSupporting or capable of supporting plantsConsists of mineral and organic materialsCharacterized by related horizons resulting from the interaction of climate and vegetation on various parent materials over periods of time and modified by relief.s = f (c.o.p.r.) t s = soil c = climate o = organisms p = parent material r = relief t = time

Tropical Soils vs. Temperate SoilsFrigid SoilsTemperate SoilsTropical SoilsTemperate SoilsFrigid SoilsTropic of CancerEquatorTropic Capricorne.g. All factors same except climate a different soil will develop depending on climate

Temperate AreaAlternating high and low temperatureWet/dry seasonWeathering/Leaching Seasonal

Fersiallitic WeatheringWeathering/Partial leaching of bases/silicaWeathering zone often < 2 mTropical AreaContinuous high temperatureWet throughout yearContinuous weathering/leaching

Ferallitic WeatheringIntensive weathering and leaching of bases and silicaWeathering zone > 10 m

ResultsSiO2/Al2O3 ratio of clay fraction > 2Weatherable minerals presentSome bases still in soilHigh CEC mixed clay mineralogyHigh base saturationpH 6.08.0Low (