SOIL A thin layer of loose material Most important natural resource because it grows food

SOIL COMPOSITION What is soil composed of Provides Oxygen and nitrogen Eroded particles of rock Binds soil & allows plants to soak up nutrients Remains of dead plants and animals = Humus

Soil Profile

LEACHING This is where the rain washes away the minerals in the top soil. The minerals are washed downwards into the bottom layers. HOW DO FARMERS DEAL WITH THE PROBLEM OF LEACHING

SOIL TYPES Ireland has two types of soil BROWN SOILS Found in places which had Deciduous forests Found in places with less rainfall They are very fertile because: * Less leaching * Contain lots of humus * Dark brown colour Best for tillage and dairy farming. South, East and Midlands of Ireland PODZOLS Found in places which had Coniferous forest or bogland Found in places with more rainfall They are less fertile because: * More leaching * Contain less of humus * Lighter in colour Used for rough grazing or forestry. EXTENSION Draw map of world and mark in Tropical Soil areas Diagram 7 p133

Tropical Climates: Central America

WHY IS IT BAD TO CLEAR A TROPICAL FOREST? Tropical Soils Tropical soil is… (Brown, Yellow, Red) Tropical forests and plants decaying on the ground cause a lot of __________________weathering. This ________________weathering gives rise to DEEP / SHALLOW soils. The ________________weathering also causes iron in the soil to change to ________________ This is why the soil looks ___________________________. WHY IS IT BAD TO CLEAR A TROPICAL FOREST?

SOIL AND VEGATATION Plant litter forms humus which helps form soil and bind soil Vegetation grows and drop leaves and litter Vegetation Helps also bind soil and stops it blowing away Fertile soil encourages more plants and vegetation to grow Soil gathers nutrients and minerals from humus and parent rocks