Land Use
DQ: 10/23 Name and Describe three ways that humans use land.
How We Use Land Land Use is measured by: Maps Aerial Photos Field Surveys Computerized mapping system
Land Use Measurements taken in California showed that in 8 years (1984-1992) nearly 210,000 acres of farmland, rangeland and woodland had been converted into suburbs and cities. Issue: How will we feed the exponential growing population?
Land Us in the United States 357 million acres of cropland 406 million acre of forestland 19 million acres of pastureland 409 million acres of rangeland
Major Concerns Major land use natural resource concerns include: erosion by wind and water maintaining and enhancing soil quality water quality and quantity plant condition and health wildlife habitat
Land Use and Land Cover Urban area: Rural area: Covered by mainly buildings and roads and defined as an area that contains 2,500 or more people. Rural area: Those areas that have relatively less people and more open space.
Agriculture: How to Feed a Growing Population Clearing land for increased agriculture Food and Agriculture Organization of the United Nations reported that the number of undernourished people in LDCs increased to over 826 million 357 million acres of cropland is threatened by urban development. North Carolina Twin Cities
Cropland Threatened Since its creation: In 1996, the U.S. government established the Farmland Protection Program: Helps protect farmland in danger of being paved over or otherwise developed. Gives financial assistances to help keep land in agriculture Since its creation: 885 million Purchased 3,993 farms
Types of Agriculture Conventional, or unsustainable agriculture Agroecology, or sustainable agriculture With a partner fill in the table:
Susceptible to soil erosion Type Conventional Sustainable Altering Land Number of crops/field Harvest After Harvest Susceptible to soil erosion Herbicide Use Pesticide Use Fertilizer Use Altering Land: Do they change the land? If so, how? (till, irrigate) Crops/field: How many different crops per field? Harvest: How often? At the same time? After Harvest: What happens to the land after harvest? (Bare or not bare)
Conventional agriculture disrupts natural ecology of the field Land get stripped for planting displacing herbivores without natural vegetation. Chemical fertilizers, herbicides and pesticides leach into the solid and groundwater Phosphates stimulate algal blooms in local streams and water sources. Single crops tend to deplete the soil of vital nutrients. Bare fields after harvesting are susceptible to soil erosion by wind and rain. Use of seeds, fertilizer, herbicides and pesticides are expensive.
Green Revolution Began in the 1940s as a way to help farmers in India and Mexico increase their productivity and relieve hunger. Developed by a plant scientist: Norman Borlaug Produced high-yield varieties of wheat that were more resistant to pests and disease. In the 1960s they developed new high-yield versions of rice, corn and beans Process called genetic engineering
Green Revolution Farmers could plant and harvest crops more quickly Helped relieve famine in Latin America and Asia However, not successful in all areas because of climate and irrigation techniques not available. Sub-Saharan Africa
Irrigation One major factor in the Green Revolution Uses about 60 percent of the world’s freshwater supplies. Different techniques: Flood or Furrow Irrigation Drip Irrigation Spray Irrigation
Rangeland Areas of land that supply forage or vegetation for grazing and browsing animals but are not managed. Land includes: Prairies Desert scrub Grasslands Chaparral (shrublands) Arctic tundra/desert Open woodlands
Rangeland Worldwide 40% devoted to livestock About 25% of the US is rangelands Areas of low to moderate rainfall (arid, semi-arid)
Environmental Problem Overgrazing: Occurs when too many animals graze for too long on a given area, exceeding the carrying capacity of the rangeland Removes vegetation and compacts soil so it not longer holds water Increased soil erosion and loss of biodiversity