soils Flashcards
what 5 elements is soil composed of ?
- mineral matter(rock)
- humus
- air
- water
- living organisms
explain rock particles.
pieces of rock resulting from the process of weathering and erosion. they contain minerals that help plants grow.
explain humus.
forms when plants and animals decay and rot. it makes soil fertile. it provides food for living organisms in the soil. the colour of soil depends on how much humus is in it. the darker the soil, the richer the humus content.
explain air.
theres air spaces between the rock particles within the soil. air contains nitrogen and oxygen which are vital to plant life. it creates air spaces to allow water to pass through.
explain water.
it can make up 25% of soil composition. it carries the minerals and nutrients to the plant roots.
explain living organisms.
soil contains earthworms, woodlice and millipedes. it contains micro-organisms such as bacteria and fungi. living organisms help to break down dead plant matter to form humus.
what is a soil profile ?
a cross section of a soil showing its layers.
what are the 6 factors of soil formation?
- climatic condition
- parent material
- vegetation
- living organisms
- water
- time
explain climatic conditions
rainfall and temperature changes determine the weathering and erosion that the rock experiences.
explain parent material.
parent material gives the rock its charecter.
explain vegetation.
when vegetation dies it is broken down by micro-organisms to form humus.
explain living organisms.
the soil is broken up by the action of living organisms.
explain water.
plant roots only take in minerals if they are dissolved in water.
explain time.
the development of soil may take thousands of years- an ongoing process - renewable resource.
what are the different soil textures?
- sandy
- clay
- loam