Chapter 4 Land and Soil Resources Section 1 Conserving Land and Soil Notes 4-1

Types of Land Use Agriculture : Agriculture : Land is the source of most of the food we eat Land is the source of most of the food we eat Less than 1/3 of land can be farmed Less than 1/3 of land can be farmed The rest is either too dry, wet, salty or mountainous The rest is either too dry, wet, salty or mountainous New farm land must be made New farm land must be made Clearing land, draining wetlands or irrigating deserts Clearing land, draining wetlands or irrigating deserts Land also is used for grazing Land also is used for grazing

Types of Land Use Development : Development : Construction of buildings, roads and bridges Construction of buildings, roads and bridges Each year in the US an area half the size of NJ is developed Each year in the US an area half the size of NJ is developed They use farmland, forests and wetlands They use farmland, forests and wetlands This destroys ecosystems and habitats This destroys ecosystems and habitats

Types of Land Use Mining : Mining : Removal of nonrenewable resources such as iron, copper or coal from the land Removal of nonrenewable resources such as iron, copper or coal from the land Strip mining: Strip mining: Removing a strip of land to get the minerals and then replacing that strip Removing a strip of land to get the minerals and then replacing that strip Causes erosion Causes erosion May remain barren without growth for years and years May remain barren without growth for years and years Underground mining: Underground mining: Using a tunnel or shaft to carry up the minerals from under the ground Using a tunnel or shaft to carry up the minerals from under the ground

What are the three types of land use?

Protecting the Soil Soil is a complex ecosystem Soil is a complex ecosystem Made of living and nonliving things Made of living and nonliving things Minerals and nutrients Minerals and nutrients Absorbs, filters and stores water Absorbs, filters and stores water Bacteria, fungi and other organisms live there Bacteria, fungi and other organisms live there

Protecting the Soil Layers of soil Layers of soil Litter: dead leaves and grass Litter: dead leaves and grass Topsoil: mixture of rock and minerals pieces, living organisms, water, air and decaying matter Topsoil: mixture of rock and minerals pieces, living organisms, water, air and decaying matter Subsoil: same material as topsoil but less decaying matter Subsoil: same material as topsoil but less decaying matter Bedrock: rock that makes up the earth’s crust Bedrock: rock that makes up the earth’s crust Takes 100’s of years to make a few cm of top soil Takes 100’s of years to make a few cm of top soil Lichen and worms break up the rock into soil Lichen and worms break up the rock into soil

Poor Soil Management Erosion: Erosion: Process by which water, wind or ice moves particles of rock or soil Process by which water, wind or ice moves particles of rock or soil Plant roots hold soil in place Plant roots hold soil in place Without plants, the soil gets moved away Without plants, the soil gets moved away Soil Conservation (p. 117) Soil Conservation (p. 117) Strip cropping Strip cropping Contour plowing Contour plowing Windbreaks Windbreaks terracing terracing

Poor Soil Management Nutrient Depletion: Nutrient Depletion: Soil becomes less fertile Soil becomes less fertile Caused by plants using more nutrients than decomposers can replace into the soil Caused by plants using more nutrients than decomposers can replace into the soil Prevention: Prevention: Leave fields fallow – unplanted with crops Leave fields fallow – unplanted with crops Leave unused parts of crops in fields Leave unused parts of crops in fields Crop rotation – plant different crops in a field each year Crop rotation – plant different crops in a field each year Corn one year, beans another, alfalfa the next Corn one year, beans another, alfalfa the next

Poor Soil Management Desertification: Desertification: Loss of so much topsoil that plants can no longer grow there Loss of so much topsoil that plants can no longer grow there Major cause is over grazing by cattle and sheep Major cause is over grazing by cattle and sheep Strip mining and cutting down trees are also a cause Strip mining and cutting down trees are also a cause Severe in central Africa Severe in central Africa In US, land 12 times larger than Texas has been affected In US, land 12 times larger than Texas has been affected

Restoring the Land Land reclamation: Land reclamation: Process of restoring an area of land to a more natural, productive state Process of restoring an area of land to a more natural, productive state Can also restore habitats for wildlife Can also restore habitats for wildlife Former mines are now agricultural land, ponds or forests Former mines are now agricultural land, ponds or forests Ex: Sheppton, PA Ex: Sheppton, PA