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5.3 Soil Degradation and Conservation - Coggle Diagram
5.3 Soil Degradation and Conservation
Reduced soil fertility
Soil Erosion
Reduced soil fertility can lead to soil erosion through the loss of essential nutrients and organic matter, which provide stability to the soil structure and promote plant growth
Without these nutrients, the soil becomes more susceptible to erosion by wind and water
When soil fertility is low, plants struggle to grow and establish strong root systems
This weakens the vegetation cover, making the soil more vulnerable to erosion by wind and water
Wind Erosion
Drier soils have their top layers consistently removed by wind.
Loss of nutrient-rich topsoil accelerates desertification.
Gullying
Channels (gullies) form on hillsides after rainfall.
Gullies deepen over time, causing more soil erosion and reduced fertility.
Sheet Wash
Large areas of surface soil are washed away during heavy rain.
Can lead to landslides and further soil degradation.
Salinization
Found in marine derived sediments, coastal location. Major problem in Australia.
Hot arid areas where capillary action bring salts to the upper part of soil.
Removal of vegetation in dry land farming
This happens when there is an excessive accumulation of salts in the soil
This can occur in arid or semi-arid regions where water evaporation exceeds precipitation
Toxification
This can occur when certain chemicals or pollutants, such as heavy metals, pesticides, or industrial waste accumulate in the soil
These contaminants can harm soil organisms and disrupt nutrient cycling
Desertification
The spread of desert-likeconditions into previously green areas causing a long term declinein biological productivity
Caused by climate change and/orby destructive use of the land.
Reduce soil cover through grazing or preparing soil for planting increase wind and water erosio
,Reducing soil nutrient and damaging soil structure.
Semi arid area: Kalahari Desert
A process where previously fertile land turns into arid desert-like conditions
Relationship between soil ecosystem, succession & soil fertility
Influence biotic factors range from organism or bacteria to humans
Bacteria fix atmospheric nitrogen converting into a usable form for plant roots
Mycorrhizal fungi on tree roots take up soil nutrients and pass them directly to the tree
Decomposes break down litter releasing nutrients into the soil
Soil organisms help to mix the soil improving its structure
Animal burrows help to aerate the soil
Animal faeces return nutrient to the soil
Indirect influence
Interception of precipitation by vegetation
Reduction of precipitation via evaporation
Types of soil degradation
Erosion by water and wind
Factor influence water erosion
Soil with high infiltration rates - high level of organic matter - greater resistance to erosion
Rain breakoff the soil aggregate material - lighter aggregate - easily remove by raindrop splash - runoff increase
Steeper the slope - increase the length of slope - greater accumulation of runoff
Increase vegetation - increase interception - reduce rain drop impacts - slow down the surface runoff - allow excess surface water to infiltrate
Factor influence wind erosion
Soil surface that are not rough and ridged offer little resistance to wind
Lack of permanent vegetation cover - extensive erosion
Loose, dry, and bare soil is most susceptible
Physical degradation
Factor
loss of structure, compaction
Caused by compaction through heavy machine or animal and cultivation in wet weather
Chemical degradation
Factor
Loss of nutrients or organic matter -reduce the capacity to support plant growth
Soil acidification - change in the composition of soil (impact of acid rain)
salinization - accumulate salts rise
Soil toxicity - caused by municipal and industrial waste
Biological degradation
Factor
Loss of organic matter and biodiversity (cause by fertilizer and herbicides) - reduce ability of soil aggregate - formation of soil crust - reduce water infiltration - increase run off and water erosion
Commbercial & Industrialized FPS
vs
Small Scale Subsistence Farming
More holistic approach to farming
relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects
large amount of chemical & energy
alters natural environment/ deforestation
deteriorates soil quality
eliminate biodiversity
minimize potential crop yield
use of heavy machine
soil more impermeable
reduce O2 content
use of fertilizers
alters soil's chemical composition
increase nutrient runoff
use of pesticides/ herbicides
increase amount of dangerous toxins
Cropping & Soil Husbandary
Methods
Maintaining crops cover as long as possible
Keeping stubble and root of the crop after harvesting
Planting a grass crop
Grass crop maintain the action of roots binding the soil
Minimize the action of wind & rain on the soil surface
Increases organic content - allows the soil to hold more water
Soil organic matter as source of plant nutrient - improve water retention & soil structure
Important as soil buffering capacity against mant threats
Avoiding the use of Marginal Lands
land that has little or no agricultural or industrial value
little potential for profit
often has poor soil or other undesirable characteristics -
Cultivation gives farmer lower yields and increasing the risk of soil degradation
Soil conservation method
Soil conditioners
Soil conditioners like compost, manure, and gypsum improve soil structure, water retention, and nutrient availability. Mulches protect the soil from erosion and moisture loss while suppressing weeds.
cultivation
Techniques like contour plowing, terracing, and no-till farming prevent erosion and improve soil structure. Crop rotation and cover cropping maintain soil fertility and protect against erosion.
wind reduction
Windbreaks, ground cover crops, and mulching reduce wind erosion by protecting the soil from wind. Erosion control fabrics stabilize soil in windy areas, preventing soil displacement.
Impact of Human
Deforestation
Soil erosion
trees cleared, increase rainfall intrusion @ wind erosion, making nutrient from topsoil runoff @ blown away, soil erodes
Soil fertility
reduce leaf litter & decaying plant matter that contribute to nutrient cycle, depletes soil fertility over time
Intensive grazing
Soil fertility
remove vegetation by grazing, reduce organic matter inputs into soil
soil compaction by livestock, reduce ability soil to absorb water & nutrient > decrease soil fertility
Soil erosion
trampled by livestock, breaking down soil structure & increasing soil erosion
vegetation removed, vulnerable to water runoff & wind erosion, soil erodes
Urbanization
Soil fertility
soil surface sealed with concrete, no organic matter input to soil, nutrient in soil decreses, soil fertility will decreases over time
Soil erosion
roads, buildings, and other infrastructure construction seal soil with impermeable surfaces, increase water runoff to other areas cause nutrient runoff too, soil eroded
(certain) Agricultural practices
Soil fertility
monoculture farming degrade soil fertility by depleting certain nutrients over time
Soil erosion
plowing, tilling especially on slopes, destroy soil structure, increase soil evaporation, less water retention in soil, soil erosion
not managed irrigation cause soil erosion through water runoff & nutrient runoff
remove protective crop cover after harvest expose soil to wind & water erosion