ESS 5.3: Soil degradation and conservation

the role of succession in soil fertility

soil ecosystems change through succession

soil erosion

the permanent change of the main characteristics of soil; it loses its fertility, pH, color, structure

overgrazing

when farmers stock too many animals on their land; the animals eat the vegetation

overcropping

when land is continuously under cultivation; land is constantly being plowed or stripped for crop growth

→ the soil becomes drier and less fertile

urbanisation

requires the removal of vegetation and top soil for construction

monoculture

leads to soil exhaustion; nutrients are replaced by chemical and organic fertilisers

factors that make soil a good growing medium for plants

organic matter

a healthy soil community

essential nutrients and minerals

a suitable pH

human activities that reduce soil fertility/deplete soil systems

deforestation → increases soil erosion

intensive grazing → increase in soil erosions by wind and water can lead to desertification

urbanisation → removes prime agriculture land

agricultural practices → irrigation, monoculture

desertification → crop failure

erosion → removes upper layers of soil, removes nutrients & minerals

soil conservation methods

soil conditioners

wind reduction techniques

cultivation techniques

use of cover crops

avoid marginal land

the relationship between soil ecosystem succession and soil fertility

fertile soil develops over a long time; as the soil develops over time, the soil becomes richer in plants and organisms

soil begins to form → simple organisms → horizons form → well-developed soil

intensive commercial farm strategies

use of tillage methods

use of monoculture

intensive use of soil; to maximise output

intensive irrigation

extensive use of pesticides

use of marginal land

subsistence farm strategies

use of tillage methods

use of polyculture (grows a range of food)

limited resources to do several harvests per season

pesticide use is dependent on funds available

high labour but limited use of fertilisers, water, pesticides