Land, Air, and Water Resources Mrs. Bloch 7th Grade Ch. 8.1 Conserving Land and Soil Essential Question: How Do People use Earth’s Resource? How do People Use Land? Why is Soil Management Important? What are the Effects of Deforestation and Urbanization? Pgs. 252-259
Vocabulary • Natural resource- is anything that occurs naturally in the environment and is used by people. • Litter- top layer of leaves and grass • Topsoil- the next layers is a mixture of rock fragments, nutrients, water, air, and decaying animal and plant matter. (absorbed by roots) • Subsoil- contains rock fragments, water, and air but has less animal and plant matter than the topsoil. • Bedrock- this is the rock that makes up the Earth’s crust. • Erosion- the process by which water, wind, or ice moves particles of rocks or soil.
Vocabulary • Nutrient depletion- when the soil becomes less fertile. • Fertilizer- nutrients that help crops grow better. • Desertification- The advance of desertlike conditions into areas that previously were fertile. • Drought- A period when less rain than normal falls in an area. • Land reclamation- the process of restoring an area of land to a more productive state. • Deforestation- people cut down woodlands to harvest timber or clear the land for farms or ranches. • Urbanization- large areas of land are developed as more and more people move to cities and suburbs.
How Do People Use the Land? Pg. 252 • Less than a quarter of Earth’s surface is dry, ice-free land. • All people on Earth must share this limited amount of land to produce their food, build shelter, and obtain resources (r. 1 p.) • . • Natural Resources • (anything that occurs naturally in the environment and is used by people.) • Land, air, and water • Three uses that change the land are agriculture, mining, and development.
3 Uses that Change the Land Pg. 253 • Agriculture- Less than a third of Earth’s land can be farmed. People create new farmland by clearing forests, draining wetlands, and irrigating deserts. Land can also be use for grazing livestock or growing food for animals, or growing crops such as cotton. • Mining- is the removal of nonrenewable resources from the land. Strip mining exposes soil and causes erosion. (r. p.) • Development- people settle in areas with good soil near fresh water. As pop. grew, the settlements became towns and cities. • Assess your Und.
Why is Soil Management Important? Pg. 254 • Soil contains the minerals and nutrients that plants need to grow. • The structure of fertile soil contains layers including: • Litter • Topsoil • Subsoil • Bedrock. • Because it can take hundreds of years to form just a few centimeters of new soil, it is important to protect Earth’s soil. • Without soil, most life on land could not exist.
The structure soil contains layers Litter, topsoil, subsoil and bedrock • Litter- top layer of leaves and grass • Topsoil- the next layers is a mixture of rock fragments, nutrients, water, air, and decaying animal and plant matter. (absorbed by roots) • Subsoil- contains rock fragments, water, and air but has less animal and plant matter than the topsoil. • Bedrock- this is the rock that makes up the Earth’s crust.
Soil Use Problem pg. 255 • Poor soil management can result in three problems: erosion, nutrient depletion, and desertification. • When plants are removed during logging, mining, or farming, the soil is exposed and soil particles can easily move. The process by which water, wind, or ice moves particles of rocks or soil is called erosion. • If a farmer plants a field with the same crops year after year, the soil becomes less fertile, a situation called nutrient depletion. When soil becomes depleted, farmers usually apply fertilizers, which include nutrients that help crops grow better.
Desertification Pg. 256 • If soil in a once-fertile area becomes depleted of nutrients and moisture, it can become like a desert. The advance of desert-like conditions into areas that previously were fertile is called desertification. • One cause of desertification is drought, a period when less rain than normal falls in an area. • The process of restoring an area of land to a more productive state is called land reclamation.
Apply IT!!Conserving Land and Soil pg. 256 Desertification Desertification affects many areas around the world. Which continent has the most existing deserts?__________ Where I the US is the greatest risk of desertification?______________ Is desertification a threat only in areas wehre there is existing deserts? Explain. Circle an area on the map to support your answer. ________________________________________________________________ If an area is facing desertification, what are some things people could do to possibly limit its effects? ________________________________________________________
Fig. 4 Conserving Land and Soil pg. 257 Land Reclamation These pictures show land before and after it was mined. Write a story about what happened to the land.
Deforestation pg. 258,259 . • 2Human processes that are changing Earth’s environment greatly: • Deforestation • urbanization • r. D & U • Deforestation, the cutting down of woodlands, affects soil, the flow of water, biodiversity and Earth’s climate. • Urbanization, the development of land to support people moving to cities, impacts land, air, and water. It decreases the amount of land available for farming, wildlife, and flood control and increases pollution of air and water
Fig. 5 Conserving Land and Soil pg. 259 Costs and Benefits of Urbanization Identify what are the costs and benefits of urbanization? Assess your Und.