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Land is made up of natural resources that are found on the earth's surface. It includes vegetation, soil, water and minerals. Land is needed for a range of purposes: Agriculture Forestry Recreation Housing Industry Businesses
Some land also needs to be set aside for wildlife and natural habitat.
Soil
Soil is a natural material found on the surface of the earth. It covers large areas of land and is made up of a mixture of: Mineral particles Organic matter Water Air
The minerals are formed from rocks. Organic matter is formed from dead and decaying plants and animal matter.
This allows organism that live in the soil to breath, and it helps plants to take up nutrients.
Organic matter
This is referred to humus. It forms about 5% of the total volume. Humus releases inorganic salts providing plant nutrients. It is also good at:
Absorbing Water Holding water Separating clay particles Binding sand particles together Providing food for micro-organisms and larger animals in the soil
Soil Structure This depends on how the soil particles cling to one another due to humus. There are 2 types of soil structure.
Single grain structure This is where the soil particles are separate from each other. Example... sand.
Properties of Single grain structure soil :
Poor water holding capacity Free drainage Low number of soil organisms
Crumb Structure Soil particles stick together in crumbs or aggregates. They are held together by humus and look like brown breadcrumbs. Eg.... garden soil.
Properties: Good aereation Good drainage Easy to dig Good water holding capacity
Types of soil
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Air
Carbon dioxide This is a gas that eis present in the atmosphere and is a renewable resource. Carbon is the building block of all living things. Plants use co2 in photosynthesis to make simple sugar. These are used with other materials to make things such as wood, leaves and fruits. ( Complex structures)
Carbon converters use co2 to make more complex structures.
Carbon sinks store carbon in many forms including trees and limestone.
Carbon sources include the burning of fossil fuels and the respiration of living organisms.
Release agents include human activity and volcanic activity.
Oxygen Oxygen in released into the atmosphere by plants and is taken up by plants and animals during respiration. Oxygen is combined with other elements to make substances like water and carbon dioxide.
Nitrogen ( N2 )
This makes up 78% of the air.
Plants need nitrogen to make substances like chlorophyll.
Nitrogen promotes better leaf growth.
FUNCTIONS OF SOIL
It provides a medium for plants to grow.
It holds and supplies nutrients to the plant in the form of mineral nutrients.
It holds and supplies water and air for use by plant roots and other organism.
It is a habitat.
Importance of Soil
Provides a habitat. Is a reservoir for water. Acts as a filter for water.
