Unit 4 Land & Water Use

TOPICS INCLUDE: • Earth Science • Atmosphere • Soil UNIT 4: LAND & WATER USE E. F. G. Mining (Mineral formation; extraction; global reserves; relevant laws and treaties) Fishing (Fishing techniques; overfishing; aquaculture; relevant laws and treaties) Global Economics (Globalization; World Bank; Tragedy of the Commons; relevant laws and treaties) people must consume 2,200 calories of food per day to live an active healthy life  area of food production unevenly distributed among population  3 main crops   wheat, rice, corn  Use of grain (corn) as energy source has contributed to rising $$ (leads to hunger due to poverty)     Industrialized agriculture  provides most of world’s food  use of heavy equipment (fossil fuel usage)  fertilizers, pesticides  high-yield monocultures Plantation agriculture  used in developing countries  grow cash crops (coffee, sugar cane, bananas, and cacao  require large input of fertilizers & pesticides  often located on cleared land (tropical forests) Traditional or subsistence agriculture  provide for ONLY 1 family’s food needs w/enough to trade or sell remaining yield for additional necessities  relies on hard work of humans & draft animals Slash-and-burn agriculture  Cutting down & burning tropical forests to clear land for planting crops & raising cattle  Farming in nutrient-poor tropical soils leads to slash-burn other section of forests   Habitat Destruction  Displaced herbivores feed off crops Eutrophication  chemicals leach into soil & groundwater  rains wash them into streams & rivers  nutrients (phosphate)stimulate algal bloom  algae prevent oxygen from reaching water beneath  aquatic organisms die  Nutrient Depletion  single crops deplete soil of vital nutrients  must replace nutrients artificially  field must be allowed to regain nutrients  Erosion  Bare  field susceptible to wind and rain Excess Costs  commercial expensive seeds, fertilizer, herbicides, pesticides are   technologically advanced agricultural practices that increased crop yield after WWII Advancements:  development of high-yielding monoculture crops  heavy use of pesticides  large inputs of inorganic fertilizer  intensive irrigation  growing multiple crops on the same plot of land during the year   Genetic Engineering: isolation of a gene from one source (plant, bacteria) for a desired trait (insect resistance), make copies of gene, then place those genes in another plant EXAMPLE: Tomatoes  ethylene production (gas produced which makes them ripen quickly)  grocers spray fruit with ethylene to start ripening process  STRATEGY: isolate gene responsible for ethylene  GE tomato (Endless Summer) does not ripen as fast longer shelf-life  GE Crops  Insect  resistance  Herbicide resistance  Virus resistance  Delayed fruit ripening  Altered oil content  Pollen control GE Crops Drawbacks  Pests & weeds could evolve resistance to GE genes (reduce effectiveness of the GE crops)  Genes can contain allergens that can be transferred  trees are cut down and/or burned  mostly occurs for agricultural reasons  in tropical LDCs slash and burn technique   soil nutrients lie within biomass of trees NOT the soil  land becomes infertile quickly Negative Consequences  tropical rainforests take up CO2; removal of trees causes CO2 to stay in atmosphere  reduces evapotranspiration; disrupts water cycle  eliminates the tropical rainforest ecosystem and species that live there (loss of biodiversity)    Brings water to agricultural crops uses about 60% of the world’s freshwater supplies Techniques  Flood    water pumped into trenches that are dug in the field & flows along the ground to the crops Simple & cheap over 50% of water does NOT reach crop  Drip     Irrigation water flows through pipes with holes in them pipes laid alongside the crops allows water to sustain them Improves efficiency by delivering smaller amounts of water more directly to crop roots for absorption More expensive  Spray   or Furrow Irrigation Irrigation Long hoses w/spray attachments are placed in field Machinery for pumping & spraying  No clear-cutting to maintain natural biodiversity  Planting many crops in the same field with different harvest times  Planting diverse crops helps build or retain disease resistance  Use of natural fertilizers  Self-sustaining farm requires less energy from farmers  Use of natural components (seeds, fertilizer, pest & weed control) reducing operating cost of farm herbicide: controls weeds  fungicide: controls fungus  rodenticide: controls rodents  insecticide: controls insects  Broad-Spectrum Narrow-Spectrum Kills many different species Selected to kill only the target •Can kill good species (bees, spiders, ladybugs) •Chlorinated hydrocarbons (DDT) •Organophosphates (malathion & parathion  occurs within specific insect populations in response to the application of a pesticide  random genetic mutation might allow a few individuals to be resistant to a pesticide   does not favor (nor harm) these species until that pesticide is widely applied  after pesticide application, this small subgroup of the population is better equipped to survive and reproduce, therefore future generations will likely contain greater percentages of members that are resistant to the pesticide. Because insect generations are relatively short, the pesticide might be rendered ineffective within a few growing seasons due to heightened genetic resistance.  force farmers to spend more money on increased amounts of the pesticide or on a different pesticide altogether  commonly referred to as the pesticide treadmill In the worst-case scenario, increased resistance, increased cost for more or different pesticides, further increased resistance, further cost ?, continues indefinitely (hence the term treadmill).  GOAL: reduce the number of pests to a economically tolerable level EXAMPLES IPM STRATEGIES  Natural enemies of pests  Crop rotation  Use of pheromones or sterile males into population to interfere with reproduction  Limited use of narrow-spectrum or natural pesticides RACHEL CARSON “Silent Spring”  1962 book “Silent Spring  Raised public awareness of the environmental consequences of DDT use  Played key role in environmental issues at the beginning of the modern environmental movement in the US FEDERAL INSECTICIDE, FUNGICIDE, RODENTICIDE ACT  Regulates the effectiveness of pesticides FOOD QUALITY PROTECTION ACT  Sets pesticide limits in food, and all active & inactive ingredients must be screened for estrogenic/endocrine effects PERSISTENT ORGANIC POLLUTANTS (POPS TREATY)  International treaty (not ratified by US in 2009) to phase out 12 organic persistent pollutants known as the “dirty dozen” such as DDT and PCBs    land where at least 10% has been or is currently covered by trees and is not build up or used for agriculture cover 1/3 of US include both commercial & non-commercial forests commercial (timber for construction, fuel & paper)  non-commercial (parks, wildlife refuges & wilderness areas  old-growth forest  Has NOT been modified by human activities or natural disasters in 200 years or more  secondary-growth forest  Formed from secondary succession   provide habitat for 2/3 of earth’s terrestrial species  tropical rainforest are home to more than 50% of world’s species  high area of biodiversity  provide crucial ecosystem services   releasing oxygen  storing CO2  reducing soil erosion  promoting nutrient recycling  influencing regional & local climate Economic Benefits  recreational activities (ecotourism)  medicines  fuelwood  jobs in lumber & paper industries  Surface fires Burn only in forests’ underbrush  Little damage to mature trees  Protect the forest from more harmful fires by removing underbrush & dead materials   Crown fires May start on ground or in canopies of forests that have not experienced surface fires  Spread quickly  High temperatures are huge threat to wildlife, human life & property   Ground fires Smoldering fires that take place in swamps or bogs  Can burn underground for days or weeks  Originated from surface fires & are difficult to detect & extinguish  Reduce Hazardous Fuels  Site Preparation  Improve Wildlife Habitat  Manage Competing Vegetation  Control Disease  Improve Forage for Grazing  Enhance Appearance  Improve Access  Perpetuate Fire Adapted/Dependent Species  Manage Endangered Species   areas of land that supply forage or vegetation for grazing and browsing animals but are NOT managed  Examples: prairies, desert scrub, grasslands, chaparral, open woodlands, riparian areas, tundras (areas with low to moderate rainfall - arid or semi-arid)  40% worldwide devoted to livestock  25% USA (mostly privately-owned)  major environmental problem is overgrazing  human population increase in industrialized , MDCs and LDCs, people tend to migrate toward cities and urban areas  environmental costs of urbanization consumption & waste production lack of vegetation microclimates water runoff solid waste & pollution noise land conversion  federal highway system increased access to many areas in US; roads traverse diverse ecosystems  construction degrades the environment  leads to urbanization  increase in pollution  National Park System  National Wildlife Refuge System  National Forest System  National Resource Lands  preservation  prevent the land from being used  methods for preserving land      remediation    purchasing legal agreements donations debt for nature swaps removal of pollutants from the disturbed land; including sediments in waterways mitigation  describe projects or programs intended to offset known impacts to an existing historic or natural resource such as a stream, wetland, endangered species, archeological site or historic structure.  to "mitigate" means to make less harsh or hostile restoration  land that has been altered is returned to pre-disturbance conditions  Minerals: nonliving natural substances  Extraction Method Open   miners dig large pit & remove exposed ore used to extract copper, iron, sand stone, gravel, limestone, granite & marble Area     Pit Surface Mining Strip Mining used on flat or rolling hill terrains dig series of parallel trenches to expose the ore after 1st trench dug & ore is extracted, used to store debris & overburden from 2nd trench at end land may be reclaimed or just left as a series of mounds of debris than then erode Contour Strip Mining Deep Mining  Worldwide & shellfish people get 20% protein from fish