Chapter 20 section 2 using land (notes)Presentation Transcript
Section 2:Using Land
A. How Land is Used 1. Land is a natural resource used by man. 2. Used for agriculture, logging, garbage disposal, urban development, and as a fuel source. a. These activities often impact Earth’s land resources.B. How Agriculture affects our environment 1. How much land can be used for agriculture? a. About 16 million square kilometers of Earth’s total land surface is used as farmland. b. The Earth has about 145 million square kilometers of land. c. Only about 11% is used for food.
B. How Does Agriculture Affect Our Environment? 2. Feeding the growing population. a. Farmers use higher yielding seeds and chemical fertilizers. b. These methods help increase the amount of food grown on each square kilometer. c. The use of these chemicals can contaminate the soil and local drinking water. 3. The use of Herbicides and Pesticides. a. These chemicals help reduce weeds, insects, and other pests that can damage the crops. b. The use of these chemicals can damage the crops and the water table.
B. How Does Agriculture Affect Our Environment? 4. Organic Farming a. Use of natural fertilizers, crop rotation, and biological pest control methods. b. Help farmers grow crops without using chemicals. c. Unfortunately this type of farming CANNOT currently produce enough food to feed all of Earth’s people.
B. How Does Agriculture Affect Our Environment? 5. Removing Vegetation for Crops a. Exposes soil to wind, water, and gravitational erosion forces. b. In some areas it can take up to 1000 years for topsoil to be replaced.
C. How Can We Reduce Erosion? 1. No-Till Farming, Cover Cropping, and Strip Cropping. 2. Terracing, Retaining Walls, Planting Vegetation. 3. Windbreaks and Shelter Beds. a. All of these are a review!!
D. Does the Land Affect Livestock? 1. Land used for feeding livestock. a. Livestock used as source of food for humans. 2. Farmers use corn and hay as livestock crops. a. Used to feed their cattle/livestock. b. These crops provide nutrients for cattle and improve the quality of the meat. c. Stop notes here.
E. What are Forest Resources? 1. Resources found in forests for medicine, fuel, and other materials. 2. ¼ of land on earth is covered with forests. 3. 55% in developing countries; 45% in developed countries.
F. What is Deforestation? 1. Deforestation is the clearing of forests for agriculture, grazing, development, or logging. 2. Amount of forested land in the world decreased by 0.24% (94,000 km2) each year between 1990 and 2000. a. Most of this deforestation has occurred in tropical climates.
G. Why the Concerns about Deforestation? 1. Tropical rain forests contain diverse populations of plants and animals that don’t live in other places. 2. Many of these plants might be important for developing new medicines. 3. Some worry that removing too much of these forests could lead to the extinction of some animals. 4. Cutting too many trees down could have a regional affect on climate. a. Water from tree leaves evaporates into the atmosphere where it can condense to form rain. b. If too many trees are cut down, less water enters the atmosphere and the region receives less rainfall.
H. How Does Development of Land Change Our World? 1. From 1990 to 2000 the amount of urban roadways in the United States increased by more than 13% 2. Paving land prevents water from soaking into the soil. a. Instead it runs off into sewers or streams. b. This increases the STREAMS DISCHARGE. 3. Stream Discharge is the volume of water flowing past a point per unit of time. 4. During heavy rainstorms in paved areas, rainwater flows directly into streams, increasing stream discharge and the risk of flooding.
H. How Does Development of Land Change Our World? 5. Many communities use underground water supplies for drinking. 6. Covering land with roads, sidewalks, and parking lots reduces the amount of rainwater that soaks into the ground to refill underground water supplies. a. This increases the chance and rate of flooding.
H. How Does Development of Land Change Our World? 6. Some businesses, communities, and private groups now preserve areas rather than pave them. a. Preserving space beautifies the environment, increases area into which water can soak, and provides space for recreation and other outdoor activities. b. See Figure 8
I. Sanitary Landfills 1. A waste-disposal area that is excavated and lined with plastic, concrete, or clay; and filled with layers of waste and dirt. a. Because of this design, the landfill is able to prevent liquid wastes from draining into ground water below. 2. About 60% of our garbage goes into Sanitary Landfills 3. Since many materials do not decompose in landfills, or they decompose slowly, landfills fill with garbage and new ones must be built. a. Type of soil, depth of groundwater, and neighborhood concerns must be considered when choosing an acceptable location for a landfill.
A. Hazardous Wastes 1. Wastes that are poisonous, cause cancer, or that can catch fire. 2. Previously, everyone-Industries and individuals-put hazardous wastes into landfills along with household garbage. a. EPA passed laws banning hazardous wastes into sanitary landfills.
B. How are some Household Wastes Hazardous? 1. Unlike Industries, individuals discard hazardous wastes in the trash. a. Insect Sprays, batteries, drain cleaners, bleaches, medicines etc. b. This garbage remains unchanged for many years and pollutes the land and water. 2. Hazardous wastes can also cause cancer and other disorders. a. Affects humans and animals that interact with the land.
C. What is Phytoremediation? 1. Hazardous substances can contaminate the soil. a. These contaminants may come from nearby industries or leaking landfills, b. Water filters into the ground and leaves toxic substances in the soil. 2. Some plants can help fix this problem in a method called PHYTO-REMEDIATION. a. Phyto- means plant b. Remediation- means to fix or remedy a problem.
C. What is Phytoremediation? 3. During phytoremediation, roots of certain plants such as alfalfa, grasses, and pine trees can absorb metals, including copper, lead and zinc from contaminated soil just as they absorb other nutrients.
C. What is Phytoremediation? 4. What happens to these plants after they absorb metals? a. If livestock were to eat the contaminated alfalfa, the harmful metals could end up in your milk or meat. b. Contaminated plants must be harvested and either composted to recycle the metals or burned. c. If the plants are destroyed by burning, the ash residue contains the hazardous waste that was in the plant tissue and must be disposed of at a hazardous waste site.
D. How are organic pollutants broken down? 1. Living things also can clean up pollutants other than metal. a. Substances that contain carbon and other elements like hydrogen, oxygen, and nitrogen are called organic compounds. i. Examples include gasoline, oil, and solvents.
D. How are organic pollutants broken down?. 2. Organic pollutants can be broken down into simpler, harmless substances, some of which plants use for growth. a. Some plants release enzymes into the soil. i. Enzymes are substances that make chemical reactions go faster. b. Enzymes from plant roots increase the rate at which organic pollutants are broken down into simpler substances used by plants for growth.
E. Natural Preserves 1. Not all land is used to produce materials or for storing wastes. 2. Some land remains mostly uninhabited by people. 3. National Forestlands, Grasslands, and National Parks in the United States are protected from many problems stated in this chapter. a. Many other countries also have Nature Preserves.