Human Interaction with soil

Overcropping

When farmland is under continuous cultivation and is not left fallow between harvests.

Example Niger

Peanut continuous growth for 3 years, 6 years needed to restore soil nutrients properly. Reduces fertility greatly.

Monoculture - cash crops like cotton

The growth of the same plant continuously. The same nutrients are used repeatedly & the soils supply lessens rapidly.

Declining harvests.

As nutrients decline harvests fail and poor farmers are forced to continue to expand their farms, eventually overcropping more of the region

Texture

Dry and dusty as result of a depleted humus source. Humus is required for fertility & improvement of soil structure

Lack of barrier

Vegetation can no longer protect from evaporation & wind erosion.

Overgrazing

When farmers stock too many animals on their land for it sustain. Results in loss of vegetation & impacts fertility as vegetation would have provided valuable humus & nutrients.

Sahel

Overgrazing common here as animal ownership defines wealth & status. Dramatically increased cattle population, land cannot sustain.

Roots

As animals eat they rip roots from the ground, contributing damage as roots provide structure to soil, & as plants reduce sheet erosion.

Evaporation

Evaporation - low water content - easily wind eroded topsoil.

Hooves on structure

Compacted & impacts percolation of water & later root growth.

Change in structure

Crumb → platy. Much less fertile structure as restricts percolation & aeration.

Sustainable farming methods

Prevent soil erosion

Strip farming, stubble planting & afforestation.

Methods of soil conservation

Strip farming

Planting alternative crops in narrow strips or bands across a field. Differ in weight harvest period & needed nutrients.

Stubble planting

Burying stubble of harvested crops back into soil. Decompose, provide humus, fertilisation without chemical/ artificial products. Prairie.

Afforestation schemes.

Process of planting new trees in areas where trees are absent.

Contribution

Roots bind soil together & act asa natural barrier against wind.

Contour ploughing terracing

Involves ploughing sloping land in accordance to the natural slope. Radial way instead of traditional up & down.