U5: Land and Water Resources

• Tragedy of the Commons

  Theory suggesting that individuals will use shared resources in their own self-interest rather than in keeping with the common good, depleting the resources.
• Regulate the use of commons by...

  • Hunting/fishing licenses
  • Land use permits
  • Country quotas (You can get this many _ per year)
  • Selective cutting of trees
• Replenish after using the commons by...

  • Replanting trees
  • Throwing back fish that are pregnant
  • Rotate which grasslands used for grazing
• Help sustain the commons:

  • Ensure compliance of treaties and laws through fines and incentives
  • Privatize the commons to incentivize care of it (does not work under all situations)
• Forest Ecosystem and Ecological Services

  • Trees help to moderate local climate
  • Part of water cycle; Help to reduce runoff
  • Part of carbon cycle
• Timber - after you cut a tree down
• Lumber - wood once it's been shaped into anything
• Forest economic benefits

  • Logging (makes furniture)
  • Ecotourism
  • Grazing for livestock
  • Aesthetics for real estate
  • Source of potential medicine
• Clearcutting - when all trees are cut down in a forest/area
• Losses from clearcutting in terrestrial environments

  • Habitat
  • Biodiversity
  • Economic opportunities
  • Food sources
  • Aesthetic Value
• Clearcutting in terrestrial environments increases...

  • Albedo
  • Soil erosion/desertification
  • Water evaporation from soil
  • Air pollution/climate change/carbon in atmosphere
• Albedo - The degree to which a surface reflects light.
• Clearcutting in terrestrial environments decrease...

  • Infiltration
  • Soil formation
  • Transpiration
• Losses from clearcutting on aquatic environments

  • Habitat
  • Biodiversity
• Clearcutting increases this in aquatic environments...

  • water temperature
  • nutrient load
• Clearcutting increases this in aquatic environments...

  • Albedo
  • Primary productivity
• Tilling - preparing land for raising crops by digging holes and removing weeds, turning over soil
• Slash-and-burn agriculture - a type of farming that involves clearing land of vegetation and burning it to use ashes for fertilizer. Usually a developing country technique.
• Impacts of tilling

  • Uncovered soil leads to soil erosion and eutrophication
  • Makes a need for fertilizer
  • Turned soil impacts soil structure negatively
  • Turned soil releases carbon as carbon dioxide into atmosphere
  • The mechanized farming equipment used releases carbon emissions, uses fossil fuels, and hurts soil structure
• Impacts of slash-and-burn practices

  • Unsustainable practice
  • Desertification
  • Soil erosion
  • Decreased albedo
  • Decreased water infiltration
• Intensive agriculture - farming that uses large amounts of fertilisers and pesticides.
• Intensive agriculture decreases genetic variety, increase pollution, and can leda to the overuses of natural limited resources.
• Haber Bosch Process - takes atmospheric nitrogen and converts it into nitrogen ammonia (used for plant growth)|

  3H2 + N2 -> 2NH3
• Synthetic fertilizer contains nitrogen, phosphorus, and potassium.
• Organic fertilizer is made up of animal manure.
• Synthetic fertilizer

  • Pros: Easy to transport and use, timed release, customizable
  • Cons: Water-soluble (can cause runoff), often overused, does nothing to improve soil structure
• Organic fertilizer

  • Pros: Can be worked into soil, contains partially-digestation vegetation (improves soil structure)
  • Cons: Must be gathered, nutrient levels unknown, harder to use
• Pesticides do NOT cause/add to eutrophication.
• • Flood Irrigation -  
  • Pros: Easy, inexpensive, mechanization not required 
  • Cons: Requires water nearby, not for all plant types, land must be graded, levees needed, 20% water lost to evaporation, water logging/salinitization 
• • Furrow Irrigation – Flowing water through small trenches that flows in between rows of crops 
  • Pros: Low investment, high-sediment water can be used, allows for some precision of application 
  • Cons: not efficient on sandy soil, soil erosion, difficult to apply in small amounts, 33% of water lost to evaporation 
• estuary - a river that flows into the sea, or a river that flows into a lake
• • Spray Irrigation – Pumping groundwater into spray nozzles across a field 
  • More efficient than flood/furrow methods, with only ¼ of water lost to evaporation 
  • More expensive and requires more energy than flood/furrow methods 
  • Pros: Precise application, supplements can be introduced into the water, can be programmed to run at certain times of day 
  • Cons: Nozzles can clog, pivot systems can wear ruts in soil can include machinery w/ fossil fuel use 
• • Drip Irrigation – Using perforated hoses to release small amounts of water into plant roots 
  • Most expensive irrigation method, but most effective w/only 5% of water lost to evaporation and runoff 
  • Pros: reduces nutrient leaching, no land grading needed 
  • Cons: clogs easily, placement makes any other processes difficult 
• • Waterlogging occurs when too much water is left to sit in the soil, which raises the water table of groundwater and inhibits plants' ability to absorb oxygen through their roots 
  • Remediate by allowing to dry out, amending soil by adding in sand 
  • Prevent w/more efficient irrigation methods 
• • Salinization occurs when salts in groundwater remain in the soil after the water evaporates. Can cause soils to become toxic over time for plants.  
  • Remediate by flushing soil with tons of fresh water 
  • Prevent w/more efficient irrigation methods 
• • Aquifers – areas of groundwater which is recharged by infiltration from rain/runoff, usually found in big porous rocks 
  • Tragedy in the aquifers - many individual farmers are taking from the an aquifer faster than the aquifer can replenish 
• • Pesticide Pros – Easy to use, increased yield and profits 
  • Pesticide Cons – Pesticide treadmills, artificial selection of resistant pests, persistence in the environment, harm/kill nontargeted species 
• Eutrophication - excessive nutrients in water, leading to excessive growth of algae.
• • GMO Pros – can be tailored to the agricultural environment and can reduce pesticide use 
  • GMO Cons – can drive selection of pesticide-resistant insects 
  • Loss of biodiversity 
  • Loss of ancestral strains of crop plants 
• 1. Two main methods of meat production: 
  2. Free-range grazing 
  3. Concentrated animal feeding operations (CAFOs)/feedlots 
  4. Demand for meat/over consumption is an issue for the developed world