Chapter 4Chapter 4 Land and Soil Land and Soil

ResourcesResources

Section 1 Section 1 Conserving Land and SoilConserving Land and Soil

3 uses that change the land are 3 uses that change the land are agriculture, development, and mining.agriculture, development, and mining.

Less than 1/3 of Earth can be farmed. New Less than 1/3 of Earth can be farmed. New farmland must be created for the growing farmland must be created for the growing populations.populations.

In the U.S. about a million hectares of In the U.S. about a million hectares of farmland is developed each year.farmland is developed each year.

Development is the construction of Development is the construction of buildings, roads, bridges, dams and other buildings, roads, bridges, dams and other structures.structures.

MiningMining

Mining is the removal of nonrenewable resources Mining is the removal of nonrenewable resources such as iron, copper, and coal from the land.such as iron, copper, and coal from the land.

Strip mining removes a strip of land to obtain minerals, and Strip mining removes a strip of land to obtain minerals, and then replacing the strip. This exposes the soil and can be then replacing the strip. This exposes the soil and can be washed or blown away. These areas can remain barren for washed or blown away. These areas can remain barren for years before they are rich enough to support the growth of years before they are rich enough to support the growth of new plants.new plants.

Protecting the SoilProtecting the Soil

Poor soil management can result in 3 Poor soil management can result in 3 problems: erosion, nutrient problems: erosion, nutrient depletion, and desertification.depletion, and desertification.

TermsTerms Litter: The very top layer of dead leaves and Litter: The very top layer of dead leaves and

grass.grass. Topsoil: A mixture of rock fragments, nutrients, Topsoil: A mixture of rock fragments, nutrients,

water, air, and decaying animal and plant matter.water, air, and decaying animal and plant matter. Subsoil: Below the topsoil, contains rock Subsoil: Below the topsoil, contains rock

fragments, water and air, but less animal and fragments, water and air, but less animal and plant matter.plant matter.

Bedrock: Soil that makes up Earth’s crust.Bedrock: Soil that makes up Earth’s crust. It takes hundreds of years to form just a few It takes hundreds of years to form just a few

centimeters of new soil.centimeters of new soil.

ErosionErosion

Is the process by which water, wind, or Is the process by which water, wind, or ice moves particles of rocks or soil.ice moves particles of rocks or soil.

Nutrient DepletionNutrient Depletion

Nutrient Depletion: When farmers plant the same Nutrient Depletion: When farmers plant the same crops in a field year after year. As a result, the crops in a field year after year. As a result, the plants use more nutrients than the decomposers plants use more nutrients than the decomposers

can replace. The soil becomes less fertilecan replace. The soil becomes less fertile..

DesertificationDesertification

The advance of desertlike conditions The advance of desertlike conditions into areas that previously were into areas that previously were fertile.fertile.

Restoring the LandRestoring the Land

Land Reclamation: The process of Land Reclamation: The process of restoring an area of land to a more restoring an area of land to a more natural, productive state.natural, productive state.

Smooth and replace strip mines with Smooth and replace strip mines with new topsoil.new topsoil.

Plant grass.Plant grass.

ReviewReview

List three ways that people use land.List three ways that people use land. What are 3 problems that can occur What are 3 problems that can occur

when topsoil is not properly when topsoil is not properly managed?managed?

Describe the effects of strip mining.Describe the effects of strip mining. Describe two methods for reducing Describe two methods for reducing

soil erosion.soil erosion.

Section 2Section 2Solid WasteSolid Waste

Every hour people throw away 2.5 million plastic bottles.Every hour people throw away 2.5 million plastic bottles. Every year people throw away enough white paper to build Every year people throw away enough white paper to build

a wall 4 meters high that stretches coast to coast.a wall 4 meters high that stretches coast to coast. Every year people throw away 1.6 billion pens, 2.9 million Every year people throw away 1.6 billion pens, 2.9 million

tons of paper towels, and 220 million automobile tires.tons of paper towels, and 220 million automobile tires.

Problem of Waste DisposalProblem of Waste Disposal

Municipal solid waste : Waste Municipal solid waste : Waste materials produced in homes, materials produced in homes, businesses, schools, and other places businesses, schools, and other places in a community.in a community.

Three methods of handling solid wasteThree methods of handling solid waste.. You can bury it, burn it, or recycle waste.You can bury it, burn it, or recycle waste.

Leachate: Polluted liquid, from the rainwater that has Leachate: Polluted liquid, from the rainwater that has

dissolved chemicals from the waste.dissolved chemicals from the waste. Sanitary Landfills: Holds municipalSanitary Landfills: Holds municipal

solid wastes, construction debris, and solid wastes, construction debris, and some types of agricultural and some types of agricultural and industrial waste.industrial waste.

IncinerationIncineration The burning of solid waste is called incineration.The burning of solid waste is called incineration.

The advantages of incinerators is that they do not The advantages of incinerators is that they do not take up as much space as landfills, they do not take up as much space as landfills, they do not pose the risk of polluting groundwater, and the pose the risk of polluting groundwater, and the heat they produce can generate electricity.heat they produce can generate electricity.

Disadvantage is that they are more expensive to Disadvantage is that they are more expensive to build.build.

RecyclingRecycling

Recycling: The process of reclaiming raw Recycling: The process of reclaiming raw materials and reusing them.materials and reusing them.

Biodegradable: A substance that can be Biodegradable: A substance that can be broken down and recycled by bacteria and broken down and recycled by bacteria and other decomposers.other decomposers.

Most recycling focuses on 4 major Most recycling focuses on 4 major categories of products: metal, glass, categories of products: metal, glass, paper, and plastic.paper, and plastic.

Products to RecycleProducts to Recycle

MetalMetal

Metals such as iron and aluminum can be melted Metals such as iron and aluminum can be melted and reused. Recycling metal saves money and and reused. Recycling metal saves money and causes less pollution than making new metal.causes less pollution than making new metal.

GlassGlass

Glass is one of the easiest products to recycle Glass is one of the easiest products to recycle because it can be melted down over and over to because it can be melted down over and over to make new glass containers.make new glass containers.

Recycling glass is less expensive than making Recycling glass is less expensive than making glass from raw materials. Less energy is glass from raw materials. Less energy is required. It also reduces the environmental required. It also reduces the environmental damage caused by mining for sand, soda, and damage caused by mining for sand, soda, and limestone.limestone.

PaperPaper

Most paper products can only be recycled a few Most paper products can only be recycled a few times. times.

Each time the paper is recycled to make pulp, the Each time the paper is recycled to make pulp, the new paper is rougher, weaker, and darker.new paper is rougher, weaker, and darker.

It takes about 17 trees to make one metric ton of It takes about 17 trees to make one metric ton of paper.paper.

PlasticsPlastics

When oil is refined to make gasoline and other When oil is refined to make gasoline and other petroleum products, solid materials called petroleum products, solid materials called resinsresins are left over.are left over.

These resins can be heated, stretched, and These resins can be heated, stretched, and molded into plastic products.molded into plastic products.

Numbers are found on the bottom of plastic Numbers are found on the bottom of plastic containers. The numbers 1 & 2 are made from containers. The numbers 1 & 2 are made from plastics that are often recycled.plastics that are often recycled.

What Can You Do?What Can You Do?

These are sometimes called the 3 R’s – These are sometimes called the 3 R’s – Reduce, Reuse and Recycle.Reduce, Reuse and Recycle.

ReduceReduce: Refers to creating less waste in : Refers to creating less waste in the first place. (Use cloth shopping bags the first place. (Use cloth shopping bags than disposable paper or plastic bags.than disposable paper or plastic bags.

ReuseReuse: Find another use for the object : Find another use for the object rather than discarding it.( Example ???)rather than discarding it.( Example ???)

RecycleRecycle: Reclaiming raw materials to : Reclaiming raw materials to create new products. create new products.

CompostingComposting

Composting: Composting: Is the process of helping the Is the process of helping the natural decomposition processes break down natural decomposition processes break down many forms of waste.many forms of waste.

Compost is an excellent natural fertilizer for Compost is an excellent natural fertilizer for plants.plants.

Examples: (Raked leaves, grass, food waste, Examples: (Raked leaves, grass, food waste, eggshells, coffee grounds and cow manure)eggshells, coffee grounds and cow manure)

Section 3Section 3Hazardous WastesHazardous Wastes

Hazardous wastes are classified into Hazardous wastes are classified into 4 categories: Toxic, Explosive, 4 categories: Toxic, Explosive, Flammable, and Corrosive.Flammable, and Corrosive.

Toxic WasteToxic Waste

Are poisonous wastes that an Are poisonous wastes that an damage the health of humans and damage the health of humans and other organisms.other organisms.

Explosive WasteExplosive Waste

Are waste that react very quickly Are waste that react very quickly when exposed to air or water, or that when exposed to air or water, or that explode when they are dropped.explode when they are dropped.

Flammable WasteFlammable Waste

Are waste that catch fire easily and Are waste that catch fire easily and can begin burning at fairly low can begin burning at fairly low temperatures.temperatures.

Corrosive WasteCorrosive Waste

Are waste that dissolve or eat Are waste that dissolve or eat through many materials.through many materials.

Radioactive WasteRadioactive Waste Are waste that contain unstable atoms. They require Are waste that contain unstable atoms. They require

special disposal.special disposal.

Health EffectsHealth Effects

Short-term exposure to hazardous Short-term exposure to hazardous wastes, may cause irritation or more wastes, may cause irritation or more severe health problems.severe health problems.

Long-term exposure to hazardous Long-term exposure to hazardous wastes, may cause diseases, such as wastes, may cause diseases, such as cancer,, and may damage body cancer,, and may damage body organs, including the brain, liver, organs, including the brain, liver, kidneys, and lungs.kidneys, and lungs.

Disposal of Hazardous WasteDisposal of Hazardous Waste

Methods of hazardous waste disposal Methods of hazardous waste disposal include burial in landfills, include burial in landfills, incineration, and breakdown by living incineration, and breakdown by living organisms. Another method involves organisms. Another method involves storing liquid wastes in deep rock storing liquid wastes in deep rock layers.layers.

Scientists have not been able to Scientists have not been able to develop completely safe methods for develop completely safe methods for disposing of radioactive waste.disposing of radioactive waste.