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What you should know by the end of this lesson:
What you should know by the end of this lesson:
Understand the factors affecting the formation of Brown Earth Soil
Be able to draw a fully annotated Brown Earth Profile
Digital Workbook and Paper Jotter
Collect the Brown Earth A4 Sheet
This can be used as a template and completed in your jotter or written on
Use the information to complete this sheet with an
The annotated diagram on one side
Soil formation factors on the other.
Complete the Check Your Learning section at the end
Where are Brown Earths found?
Where are Brown Earths found?
Brown Earths are mostly located between 35° and 55° north of the Equator. The largest expanses cover western and central Europe, large areas of western and Russia, the east coast of America and eastern Asia. Brown Earths cover 45% of the land in England and Wales.
Brown Earth - soil formation
Brown Earth - soil formation
Vegetation: Deciduous forests with a large variety of plants & trees which creates a mild acid (mull) humus
Organisms (Biota): Warmer temperatures means there is large amounts of biota (worms & moles) meaning the soil is well mixed giving less defined horizons
Relief: Found in more fertile flatter lower slopes creating mild climates
Climate:
Lower precipitation than podsol means less Leaching of minerals less chance of creating an iron pan which gives a more fertile stronger colour.
More chemical or biological activity due to the mild temperatures which means there is more decay at the surface
Parent Material: Variable acidic/alkaline e.g. sandstone & Limestone
Drainage: better drainage than podsol meaning less waterlogging creating more fertile soil than podsol
Annotated Soil Profile
Annotated Soil Profile
Annotated Soil Profile
Annotated Soil Profile
1:E(zone of eluviation)
2: Precipitation = Evaporation (> in winter, slight leaching)
3: Tree roots penetrate deep in the soil & take up bases
Location - broadleaved deciduous forests of Western Europe.
Trees have deep roots.
Leaching is less pronounced.
O horizon rich in nutrients due to input of decaying fleshy deciduous leaves in Autumn.
Litter decomposes relatively quickly due to milder climate. The result is a less acidic mull humus.
Deep tree roots penetrate down to C horizon and extract minerals to ensure nutrient cycling. This allows chemicals lost by leaching to be brought back up. Extensively used for agriculture.
Brown earth forms on gently sloping and low lands. The land is well-drained and allows biological activity
Indistinct horizon boundaries – Soil is well mixed due to earthworm and soil bacteria activity.
A horizon – well-aerated, humus enriched mineral soil (pH 5.8). Dark brown in colour because humus replaces minerals that are leached out.
B horizon not so distinct as in podzol but is usually lighter brown in colour due to less humus.
C horizon derived from varied parent material ranging from limestone to schist.
Well done you have finished lesson 4 of Biosphere
Well done you have finished lesson 4 of Biosphere
Return to the topic launch page and attempt the lesson quiz
Return to the topic launch page and attempt the lesson quiz
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