quiz 2 lecture vocab Flashcards
soil formation due to… (2)
- break-up/weathering of rocks -> minerals
- decay of organic matter
the earth is alive w/ detritivores and microbes
98% of human food comes from land
land distribution percentages
- crop cultivation: 12%
- livestock grazing: 24%
- forest: 31%
- desert/mtns/tundra/unsuitable: remaining 33%
natural soil cycle (3)
- degredation: solution and leaching of nutrients by water
- erosion: removal of topsoil by wind/water
- balance: degredation + erosion = soil formation
anthropogenic soil problems
- human activities
- agriculture
- impervious surfaces
- landscape -> wind pattern & hydrologic alterations
- consequences
- 2.5x erosion & degredation
- declining crop & livestock yields
probs w/ industrialized agriculture
- expansion of land ended in 1950s -> intensive ag:
- high productivity
- monocultures
- high energy & chemical inputs
- cultivation of marginal & hilly lands
- little to no crop rotation or fallowing (allowing soil to reform)
- overgrazing
- 1/3rd of soil lost by 1996
- declining yields despite chem applications
dustbowl of 1930s led to the…
- Conservation Reserves Program, which was sort of started in 1956 but not truly implemented until the 1985 farm bill
- encouraged conversion of erodible lands to grass/woodlands
- penalties for non-participant farmers
- reduced soil loss by 65%
top soil is lost 16x faster than it forms and Great Plains States have lost 50% of their top soils since ag began because…
People! All the science and technology won’t help if people’s behavior doesn’t change
social norms influence behavior more than environment (recall the hotel room and the re-use message: “people who stay in this room re-use their towels”)
practices that reduce soil losses (5), which increase nutrient recycling and soil formation
- Terracing
- Contour planting
- Multiple cropping
- conservation / low tillage
- organic fertilizers / composting
- (ex: Shanghai self-sufficient in veg since ’80s)
small vs. big farming
smaller, privately owned farms:
- more labor instensive, but also more productive
- small scale farmers more likely to care for land than large corporations
large scale mgmt:
- encourages application of technology
- price reforms encourage profitability
- changes in land tenure / ownership rules
- increased food prices: political dynamite
human uses for water (7)
- drinking / cooking / cleaning
- habitat
- recreation
- transportation
- industry
- source of energy
- agriculture (~70%)
- 1.1M Gal to grow 2.4 acres of corn
problems w/ human uses of water (5)
- uneven distribution
- source of political conflict
- slow recharge rate (~1%)
- Up to 80% of irrigation lost to evap. and seepage
- withdrawals > recharge
- depleting aquifers -> cone of depression
- water pollution
water probs: climate change might…
shift the playing field and re-orient conflict
- San Joaquin Valley, CA (salad bowl)
- L.A. & San Diego draw water from Colorado river -> Cadillac desert
- Nile River Basin: Sudan & Ethiopia vs. Egypt
- Kasmir River Basin: India (dam) vs. Pakistan
- Ganges River Basin: India (dam) vs. Bangladesh
addressing water problems means improving efficiency and conservation. Current water tech could… but…
save up to 50% of ag use, 90% of industrial use
- ex: drip irrigation: targeted (less weeds), & slow (less evap.)
- raise water prices certain uses (water parks, maybe?)
… but isn’t being used because of culture
4 dimensions of social systems
- culture
- community
- economics
- politics
diverse ecosystems…
- are more Productive: due to complementary resource use
- are more Sustainable: they conserve & more effectively use water & nutrients
- fill more Functional Roles: seed dispersal, pollination, etc.
- are more Adaptive to change/stress
- Provide a variety of food, medicine, & other commercially important materials
- Pacific Yew Tree bark -> taxol