Human Activites That Cause Soil Erosion And Degradation Flashcards
Why is vegetation removal causing soil loss
Removing vegetation leaves the soil exposed to the processes of wind and water erosion
There is no longer roots to bind the soil or organic matter to create the humus that hold the soil together
What is the benefits of ploughing
Breaks up the soil allowing it to be aerated and easier for roots to grow
What is the problem with ploughing
Breaks up the soils structure so the soil particles are no longer in larger clumps so are more at risk of soil erosion
Only disturbs upper layer while compacting the lower soil layers
What is overgrazing
When there are too many animals on a the same land for an extended period
What are the problems with overgrazing
Animals eat the vegetation so much there is nothing left to protect the soil from wind and water erosion
Animals also damage roots meaning the soil is no longer held together
What is the job of soil biota
To break down organic matter
What is the importance of organic matter
Improved soil structure making it less prone to soil erosion
Why are worms important
Increase infiltration by aerating the soil reducing surface runoff
What causes soil compaction
Farm machinery
Large herds of livestock
What is soil compaction
When the pore spaces in the soil are squashed reducing aeration levels
What is the problem with soil compaction
Creates an anaerobic environment so decomposition is reduced
Reduced soil infiltration increases soil erosion
what was the cause of the 2014 Somerset flood
highly sedimented rivers which reduced the rivers capacity
why did the Somerset flood occur (Human cause)
the rivers had not been extensively dredged for 20 years meaning flow was dramatically reduced
what is sediment
loose deposited material
what is the problem with soil erosion reaching a reservoir
means the reservoir has reduced storage capacity.
will require dredging which is costly and time consuming
what are the positive of sediment reaching the ocean
increases the rate of delta formation
what are the negatives of sediments reaching the ocean
Eutrophication- pesticides and nitrates causes algae bloom killing aquatic plants and the fish that rely on the plants for oxygen
Can settle on corals
what are particles in the atmosphere called
known as atmospheric particles
what is the problem with atmospheric particulates
most important causes of air pollution
can trigger asthma
where is the production of atmospheric particulates most likely
flat and bare areas
dry and sandy soils
what is desertification
occurs when productive but arid land turns to desert
how can soil erosion increase the risk of landslides
- erosion makes it difficult for plant growth, plant roots hold the soil together and absorb water reducing separation of soil
- erosion creates channels that promote landslides
what are long term crops? (definition)
crops that do not require planting every year once grown they can remain in the soil
no need to plough (break up the soil)
Usually large so act as a windbreak (windblow)
what are some examples of long term crops
fruit trees, coffee, nuts (almond + walnuts)
what is contour ploughing
where the field is ploughed at 90 degrees to the slope angle
how does contour ploughing reduce soil erosion
water doesn’t flow all the way down the slope so the the soil remains relatively stationary
what is tied ridging and what is needed for it to take place
on flat fields
involve planting crops in a criss-cross of intersecting ridges
what are the positives of tied ridging
increases infiltration and reduces runoff.
why are windbreaks used?
good solution to wind blow as they reduce wind velocity
where does terracing occur
where the land is heavily sloped fields are cut into the slope to create a terrace
what do they do the hold the soil in place (terracing)
build walls to hold and retain the soil
what are the positives of terracing
helps in filtration as the terraces are flat allowing more time for water to be absorbed
what is multicroppiing
growing more than one crop in a field
what is strip cropping
wide strips by a tractor
strips are grown at 90 degrees tot eh prevailing wind reducing wind erosion
what is mulching
addition of organic matter
decomposition of organic matter creates the humus layer
why is the humus layer important
make soil particles stick together more effectively
what is mulch
any material laid over the soil surface
bark, straw composted manure
what is no tillage
no ploughing occurs seeds are instead drilled directly into the ground
prevents breaking of soil damaging its structure
