soil and acid precipitation
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Soil and acid precipitation. Soil is what sustains plants. Plants are what sustains ecosystems. What is Soil?. Soil…. It is more than just dirt!! Soil has many life forms within it, and this life is crucial for the health of the ecosystem it is in. - PowerPoint PPT PresentationTRANSCRIPT
SOIL AND ACID PRECIPITATION
Soil is what sustains plants.
Plants are what sustains ecosystems
What is Soil?
Soil… It is more than just dirt!! Soil has many life forms within it, and this
life is crucial for the health of the ecosystem it is in.
Soil is a loose covering over the ground that contains organic matter, minerals (rocks), and moisture.
To assess soil quality, we must look at Soil profile Soil Type Acidity
Soil ProfileThere are three distinct layers to the composition
of soil:1) Topsoil – O and A layers.
It is composed mostly of humus, which is decaying organic matter. It has rocks and many organisms like bacteria, fungi, insects and worms.
2) Subsoil – B layerIt is very compact and has little or no organic matter except roots of very large trees and bacteria
3) Regolith and bedrock – C and R layersThe regolith is composed of large chunks of rock, and the bedrock is solid rock. Water cannot pass through bedrock, so it pools here. This is where aquifers (groundwater) are located.
50% pore space
50% solid
material
25% air
25% water
45 to 48%
mineral matter
2 to 5% organic matter
Volume composition of a desirable surface soil
Not all soil has this balance – only the most desirable soil. For example, C layer soil is mostly mineral matter. It has little water and air, and no organic matter.
Soil Particles All soil originated from bedrock,
therefore all soil is made up minerals (weathered rock)
The weathered rock is known as soil particles. The soil particles are classified from largest to smallest as sand, silt, and clay
Types of Soil 1) Sand:
Relatively large particles
Feels coarse and gritty
Creates large spaces that permit root growth and air pockets for plants
Water drains too easily, taking nutrients away from roots of plants
Types of Soil2) Silt:
Fine particles, a muddy texture
Easily transported by water, so it is found in and along rivers and wetlands
Soil drains slowly, so it facilitates plant growth. However, the soil also erodes easily.
Human activities such as logging and bad farming practices result in unwanted silt being washed into rivers, which is a pollutant
Types of Soil3) Clay:
Very fine particles Particles are
packed tight together, so there are no air pockets. It is dense.
Clay traps water so it is often very wet and sticky.
Plant growth is difficult.
Types of Soil4) Loam
Has rock particles of different sizes (sand, silt, and clay) and pockets that hold air or water
Has lots of humus Drains well without
drying out Plants grow easily Has a dark brown or
black colour
Types of Soil Which soil type do you think is best for
agriculture?
Human Impacts on Soil Soil Erosion: The loss of soil when water or
wind blows it away. This occurs when soil is ploughed or tilled and the
topsoil is exposed to wind and water which causes it to erode.
Occurs due to overgrazing by livestock or too much ploughing for farming
If the top soil is gone, the nutrients are gone.
Human Impacts on Soil Fertilization: The process of a farmer adding
extra nutrients to the soil to make plants grow bigger and faster Without fertilizers, many farmers would not be able to
grow as much food Manure is a natural fertilizer Artificial fertilizers are common nowadays – they are
synthetic chemical compounds of nitrogen, phosphorus, etc.
This fertilizers wash away from the soil and pollute local water bodies. It results in excessive algae growth (eutrophication).
Human Impacts on Soil Leaching: The process by
which soil receives a lot of water, and the nutrients in the topsoil wash downward, making them unavailable to plants. In wet environments, such as
rainforests, this occurs naturally. This is why rainforests are not good for farming.
When humans overly water soils, nutrients are leached from the topsoil. Sandy soil gets leached easily. Why is this?
Humans Impacts on Soil Crop Rotation: The
practice of planting a different crop in a field each year. This is good for the soil. This replenished the
nutrients in soil Crops such as legumes,
help put nitrogen in the soil since they have nitrogen-fixing bacteria
If crops are not rotated, the nutrients in the soil get used up and crops will no longer grow well.
Acidity of Soil Acidity is another factor in soil quality We use the pH scale to assess the acidity
level of soil
Acidity of Soil If soil has a low pH (0-7) it is considered acidic If soil has a high pH (7-14) it is considered
alkaline Most plants and organisms prefer a neutral
environment If soil is too acidic or alkaline it can harm plants:
The roots that absorb the plants’ nutrients are damaged
The waxy coating on plants’ leaves that prevents it from infection is damaged
However, some plants do require slightly acidic or alkaline pH levels
Earthworms in the soil are also harmed because their skin gets burned
You will also have an opportunity to do you Soil Lab ISU on acidity
Acid Precipitation Acidic soil is the result of
Acid Precipitation Acid precipitation
describes any form of rain or snow with high levels of nitric and sulfuric acids.
It is 40 times more acidic than normal rain
When humans burn fossil fuels, sulfur dioxide and nitrogen oxides are released into the atmosphere, which react with water, oxygen, and other substances to form mild solutions of sulfuric and nitric acid.
Sources of Acid Precipitation
• Emissions come from coal burning plants, cars, metal smelters and oil refineries
• However, Cars are the biggest cause of acid rain by burning fuels
• Although countries have emission standards on cars there are more and more cars being driven.
A forest affected by acid precipitation
Aquatic Impacts In addition to soil, acid precipitation
affects aquatic ecosystems: lakes, streams, wetlands, and other aquatic environments
Acid rain makes waters acidic and causes them to absorb the aluminum that makes its way from soil into lakes and streams. This combination makes waters toxic to crayfish, clams, fish, and other aquatic animals.
Shellfish are particularly sensitive because the acid dissolves their shell
Action on Acid Precipitation
When scientists discovered the damaging effects of acid precipitation, governments put limits of emissions
Factories have installed scrubbers in their smoke stacks, which remove a large proportion of the damaging chemicals from the emissions before they’re released into the air
Acid precipitation has been reduced, but countries that have not implemented emission standards continue to produce pollution – which is carried by wind. Therefore, acid precipitation is a global problem.
HomeworkRead pages 70-75
Soil Page 75 #1-5 Page 85 #3, 13, 14
Acid Precipitation Page 85 #11, 15, 16