SOIL FORMATION ClimateReliefVegetation DrainageParent MaterialSoil Biota Study the diagram below. Describe the influence of the various soil forming factors on the formation of a Podsol soil. 10 Marks

SOIL FORMATION Climate ReliefVegetation DrainageParent MaterialSoil Biota Cold, wet climates Thin: Weathering is slow Thin layer of humus: Humification is slow A lot of Leaching and Podsolisation Iron and Aluminium pushed down Northern Latitudes Moorland Coniferous Forests Needles don’t decompose easily little humification Produce an acid humus A Horizon often waterlogged because of impermeable iron pan that forms inbetween A and B horizon. Weathered Slowly producing a shallow soil Few Biota because cold climate Therefore, little humification

Mature soils have 3 distinct horizons (layers) A Horizon – Contains topsoil, humus, vegetation not decayed, biota The most fertile part of the soil Suffers the most leaching B Horizon - Contains subsoil Contains leached mineral from A horizon C Horizon - The Regolith (recently formed soil) Sits ontop of bedrock Contains large particles.

Brown Earth Soils They form in warm climates, with mild winters and summers. Found in areas that have rainfall all year. Found in areas of deciduous forest Weathering is quite slow due to cool climate Some Humification because deciduous trees shed leaves every year. Mild climate assist decomposition Lots of biota in these soils due to climate. Some Leaching – because precipitation exceeds evaporation.

What does it look like? Quite shallow Quite thick Humus Mild Acid Humus Light Brown A Horizon – because calcium, magnese are leached out by rain Dark Brown B Horizon – because minerals have been illuviated here. Horizons often Merge These are the main characteristics of the Brown Earth Soil. Explain why these soils have these characteristics eg. Quite shallow because of slow weathering. Which is due to the cool climate etc.

What does it look like? Quite shallow - weathering is slow Quite thick Humus – because there is some humification Mild Acid Humus – because humification is slow Light Brown A Horizon – because calcium, magnese are leached out by rain Dark Brown B Horizon – because minerals have been illuviated here. Horizons often Merge - biota mix the soil