Soil Degeneration is the Decline in the usefulness of a soil.
Types of soil degeneration
Physical soil degeneration
This is a Decline in the use of soil in which texture, structure, moisture, and quality of soil are affected.
causes of physical soil degeneration
- Deforestation which leads to the removal of vegetation which forms a protective cover of the soil exposing it to erosion agents.
- Overgrazing which causes excessive loss of water from the soil causing it to become loose and fine-grained and easily eroded.
- Poor Cultivation Techniques
i) Pulling hoe along the surface when removing weeds which loosen the soil and when it rains its washed away.
ii) Ploughing of land downslope which accelerates soil erosion.
iii)Cultivation of steep slopes and along river banks which encourages soil erosion.
iv) Burning which destroys vegetation covering the soil exposing it to erosion agents.
v) Growing crops on the same piece of land from season to season sucks nutrients from the soil making it fine, loose, and easy to be eroded.
vi) Planting crops such as maize whose foliage doesn’t provide adequate soil cover encourages soil erosion.
vii) Cultivation in areas that suffer prolonged droughts which loosen the soil causing it to be exposed to erosion during dry seasons.
- Heavy rain resulting in excessive soil erosion and thus poorly aerated.
- Drought deprives the soil of moisture which holds the soil together causing particles to loosen making it to be easily brown by the wind.
- Excavation works such as quarrying, open-cast mining, building of estates and road construction which loosen and expose the soil to erosion agents.
- Soil erosion which robs the soil of top fertile layer.
Chemical soil degeneration
this is the decline in usefulness because of changes in mineral nutrients of the soil.
Causes of chemical soil degeneration
- Leaching which makes minerals inaccessible to shallow rooted crops.
- Excessive application of fertilizers which interferes with bacterial activity and causes the soil to become too acidic and unable to support a variety of crops.
- Excess water causing water logging causing acidic conditions.
- Planting one type of crop repeatedly which makes the soil deficient of some nutrients.
- The excessive drought which causes the accumulation of salts in the topsoil.
- Burning such as in slash and burning kills micro-organisms causing nitrogen deficiency when nitrogen-fixing bacteria is killed.
Biological soil Degeneration
Degeneration due to decline of organic content of the soil and organic matter.
Causes of biological soil degeneration
- Deforestation deprives the soil of its organic content and moisture making it loose and more vulnerable to erosion.
- Burning such as in slash and burning which kills micro-organisms causing a low decomposition rate which robs the soil of organic matter.
- Overgrazing causes the removal of vegetation causing excessive loss of water from the soil and hence reduced micro-organism activity resulting in a shortage of humus.
- Drought and excessive moisture may lead to a shortage of essential organisms such as bacteria, earthworms, termites, and burrowing animals.