Midterm 2 Flashcards
(122 cards)
How is the majority of land on earth used?
Cropland and rangeland.
Cropland
20% of all surface land is needed for agriculture to feed. Equal to the size of Africa.
Rangeland
Grazing livestock, meat and dairy.
Land use extensification
When natural ecosystems are converted into areas for human use
Land use intensification
Increasing the intensity of human land use
Issues with land use intensification
More fertilizers- more pollution
More resistant plants
Urbanization
Increase in proportion of people living in urban areas.
- overall population increasing
- rural population decreasing
Issues with urbanization
Waste, pollution, urban sprawl, transportation
Reforestation
Complicated: rows of the same trees (monoculture), costly to recreate an entire ecosystem, selective harvesting
Deforestation causes
Wood products, fuel, cropland, rangeland.
Ex) Brazil and Australia
Reforestation
Replanting trees
Aforestation
Planting trees where there were none previously
Impacts of deforestation
- carbon released by burning and decomposition of trees and other plants
- loss of ability to absorb carbon
- carbon from fossil fuels burned in process of deforestation
Issues with cropland
- loss to urban sprawl
- soil degradation: erosion, salinization, water logging
Rangelands
- quickly cause irreversible erosion, especially in semi-arid places. ex) Australia
- overgrazing
- rotational grazing
Desertification
Land degradation in arid location, eventually becomes desert
Future of land use
Cities: high density, mass transit, less energy use.
-eat lower on the food chain. Requires less resources.
4 challenges for increased agriculture production?
Irrigation, soil, tillage, fertilizer
Irrigation
Increasing complexity and demand for water.
- salination of soils (inadequate drainage and evaporation)
- leads to desertification (loss of vegetation)
- decline in freshwater bodies (ex. Aral Sea)
Soils
Soil erosion.
Techniques to prevent soil erosion
- manuring
- fallowing and crop rotation
- terracing sloped fields
- maintaining vegetation cover
- importance of understanding soil types
Types of tillage
Strip/zone tillage, minimum tillage, zero tillage
3 functions of tillage
- provides a seed bed
- controls weeds
- incorporates organic matter
Fertilizer
NITORGEN.
-naturally from the atmosphere, but not enough.
-in farmed soils it reduces over time.
Ways to increase nitrogen is by using manures and planting legumes