Unit 5 - Land and Water Use Flashcards
tragedy of the commons
- when individuals use shared/public resources in their own self interests degrading them
- must be a public resource (not privately owned)
examples of tragedy of the commons
overgrazing, overfishing, water and air pollution, overuse of groundwater
why does tragedy of commons occur
- when no one owns the resource, no one directly suffers
- people assume others will overuse it if they dont
- no penalty for overusing
externalities
negative costs associated with human actions that aren’t accounted for in the price (unintended side-effects)
overfishing
can lead to fishery collapse (population crash), loss of income and starvation
pesticide runoff
from farms contaminates drinking water
how to solve TOC
- private land ownership
- fees or taxes for use
- taxes, fines, criminal charges for pollution of shared soil, air, water resources
clearcutting
practice in which most or all trees in an area are uniformly cut down
direct effects of clear cutting
- soil erosion
- increased soil and stream temp
- flooding an landslides
what replaces clear-cuts
tree plantations
effects of tree plantations
- lowers biodiversity
- all the same age (lowers biodiversity more)
slash and burn
method of clearing land for agriculture by cutting trees and burning them releases CO2, N2O, and water vapor into the atm.
- return nutrients in plants to soil
green revolution when and where
- 1950s to late 1960s
- where: worldwide but major impact on developing countries like Mexico and India
what was the green revolution
a shift in agriculture away from small family operated farms to large industrial scale agribusiness
- increase in productivity due to higher yield crops that were pest and disease resistant
- increased use of mechanization, GMOS, irrigation, fertilizers,
- short term profitability
consequences of green revolution
soil erosion, loss of biodiversity, ground surface water contamination, requires massive input of water
mechanization
introduction of machinery
mechanization: pros
increased use of tractors for plowing and tilling fields = increased yield and profits
mechanization: cons
- increased reliance in fossil fuels
- emits GHGs
- heavy machines compact soil. decrease water holding capacity
high yield variety crops
- hybrid or genetically modified crops that produce a higher yield (amt of crop produced per unit of area)
GMOs
genetically modified crops that have genes for drought tolerance, pest resistance, faster growth, larger
GMOs: pros
increases profitability with fewer plants lost to drought, disease, or pests; larger plant size
GMOs: cons
crops are genetically identical so genetic diversity is decreased and susceptibility to diseases or pest is increased
synthetic fertilizer
shift from organic fertilizer (like manure and compost) to man made NH4, nitrate, phosphate
synthetic fertilizer: pros
increased yields and profits with more key nutrients
irrigation
drawing water from the ground or nearby surface waters and distributing it on fields to increase plant growth
irrigation: pros
make ag. possible for parts of the world that are naturally too dry (dont receive enough rain)
irrigation: cons
- can deplete groundwater sources, esp. aquifiers
- overwatering can drown roots and cause soil salinization
example of pesticides harming nontarget species
- DOT thinned shells of bird eggs, especially eagles
- atrazine turns amphibians and fish intersex
monocropping
growing one single species (corn, wheat, soy) of crop
monocropping is highly efficient for
harvest, pesticide, and fertilizer application
negatives of monocropping
- greatly decreases biodiversity
- increases soil erosion (crops harvested all at once and soil left bare)
- decreases habitat diversity for species living in an area
tilling
mixing and breaking up soil to make planting easier; loosen soil for roots
negatives of tilling
- increases erosion by loosening topsoil, breaking up leftover root structure from harvest
- loss of organic matter and topsoil nutrients over time
- increases PM in air
furrow irrigation
- trench dug along crops and filled with water
- easy and inexpensive, water seeps into soil slowly
- 66% efficient, 33% lost to runoff and evaporation
drip irrigation
- most efficient
- MOST COSTLY
- holes in hoses allow water to slowly drip out
- avoids water logging and conserves waters
flood irrigation
- flood enters field; easier but more disruptive to plants
- can waterlog the soil and drown plants
- 80% efficient, 20% runoff and evaporation
spray irrigation
- ground/surface water pumped into spray nozzles
waterlogging
- overwatering can saturate the soil, filling all soil pore space with water, depriving roots of oxygen
solution to waterlogging
drip irrigation or soil aeration- poking holes in soil to allow air in and water to drain out
largest human use of freshwater
is for irrigation (70%)
soil salinization
- process of salt building up in a soil over time
solution to soil salinization
- drip irrigation
- soil aeration
- flushing with fresh water
- switch to freshwater source
global human water use
- Agriculture: 70% (water for livestock, irrigation)
- Industrial: 19% (power plants, metal/plastic manufacturing)
- Municipal: 11% (households, toilets, shower)
groundwater
h2o stored in pore space of permeable rock and sediment layers
aquifer
- layer of permeable rock which can contain or transmit groundwater
- replenished by groundwater recharge (rain percolating down through soil into aquifer)
ogallala aquifer
- central USA
- aquifer was severely depleted bc it was overused for agricultural irrigation
CAFO
concentrated animal feeding operation (to raise them asap)
- AKA feedlots
CAFO: pros
- maximizes land use and profit
- minimizes cost of meat for consumers
CAFO: cons
- given antibiotics and growth hormones to prevent disease outbreak and speed meat production
- animals produce large volume of waster which can contaminate nearby surface or groundwater
- produces large amounts of CO2, CH4, and N2O
manure lagoons
large, open storage pits for animal waste
- waste contains NH3, hormones, antibiotics, fecal coliform bacteria (e-coli)
- denitrification of NH3 in manure produces N2O (powerful GHG)
- antibiotics and growth hormones -> endocrine disruptors
free range grazing
animas (usually cows) graze on grass and grow at a natural rate without growth hormones
overgrazing
- too many animals feed on a particular area of land
overgrazing effects
- loss of vegetation
- soil erosion
- desertification
fisheries
population of fish used for commercial fishing
fishery collapse
- when overfishing causes 90% of population to decline in a fishery
- pop. may never recover due to decreased biodiversity, inability to find mates, inbreeding depression
bottom trawling
- harmful fishing method that involves dragging a large net along ocean floor
- mixes up sediment (turbidity) and destroys coral reef structure
ore
commercially valuable deposits of concentrated minerals that can be harvested and used as raw materials
metals
elements that conduct electricity, heat, and have structural properties for building (found in ores)
mining reserve
the known amount of a resource left that can be mined
- usually measured in years left of extraction
overburden
- soil, vegetation, and rocks that are removed to get to an ore deposit below
mining tailings and slag
- leftover waste materials separated from the valuable metal or mineral within ore
surface mining
- removal of overburden to access ore near surface
- diff types: open pit, mountaintop removal
- mtn. top removal is esp. damaging to landscape and habitats, stream nearby - removal of vegetation and soil
subsurface mining
- more expensive due to higher insurance and health care costs for worker
- risks: poor ventilation leading to toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos
- vertical shaft drilled down into ground; elevator to carry
- increasingly used as surface coal deposits are depleted
environmental impacts of mining
- rainwater carries sulfuric acid into nearby streams, or infiltrates groundwater
- lowers pH of water, making toxic metals like Hg and Al more soluble
- CH4 release
- PM release
mine reclamation
process of restoring land to original state after mining has finished
urban sprawl
population movement out of dense, urban centers to less dense suburban areas surrounding the city
ecological footprint
measure of how much a person or group consumes expressed in area of land
carbon footprint
all CO2 released from an individual or groups consumption and activities
- measured in tons of CO2 produced per year
maximum sustainable yield
the max amount of a renewable resources that can be harvested without reducing or depleting the resource for future use
IPM
using a variety of pest control methods that minimize environmental disruption and pesticide use
biocontrol
introducing a natural predator, parasite, or competitor to control the pest population
crop rotation
rotating crops can prevent pests from becoming established since it disrupts their preferred food source
intercropping
- push pull system
- push plants emit volatile chemicals that naturally repel pests away from crops
- pull plants emit chemicals that attract pest predators
contour plowing
- plowing parallel to natural slopes of the land instead of down slopes prevents water runoff and soil erosion
- forms mini terraces that catch water running off, conserving Soil and Water
terracing
- cutting flat platforms of soil into steep slope
- flatness of terraces catches water and prevents it from becoming runoff in eroding soil
perennial crops
- crops that live year round and are harvested numerous times
- longer, more established roots and prevention of bare soil between harvest
wind breaks
- using trees or other plants to block the force of the wind from eroding topsoil
- can be used as a source of firewood, fruit (income)
- can provide habitat for pollinators and other species
no till
- leaving leftover crop remains in soil instead of tilling under
- adds organic matter to soil (nutrients, soil cover, moisture)
- prevents erosion from loosened soil
strip cropping
- another name for intercropping
- alternating rows of dense crops (hay, wheat) with rows of less dense crops (corn, soy, cotton) to prevent runoff from eroding soil from less dense rows of crops
aquaculture
raising fish or other aquatic species in cages or enclosures underwater
why has aquaculture expanded
highly efficient, requires only small areas of water, requires little fuel
drawbacks of aquaculture
- can contaminate waste water
- fish that escape may compete or breed with wild fish
- density of fish can lead to increases in disease outbreaks and may transmit to wild fish
methods for mitigating deforestation
reforestation, using and buying wood harvested by ecologically sustainable forestry techniques, reusing wood
prescribed burn
method by which forest are set on fire under controlled condition in order to reduce the occurrence of natural fires
