Soil: an ecosystem with abiota (rocks, water, etc.), biota (worms, bacteria, etc.) and detritus
    soils often stratified.  type of soil depends on climate, biota, original starting material...
       humus:  uppermost dark layer rich in organic material both alive and dead.  produces acids
       A horizon/topsoil:  porous layer, often leached by downward migrating acidic water
       B horizon/subsoil/regolith:  partly altered rock or sediment, rich in clay minerals (crystals)
            minerals (e.g. quartz) often grow and accumulate/precipitate in this zone
       C horizon/bedrock:  fresh solid rock or fresh sand, gravel, mud, etc.

Soil Formation and Destruction: soils form very slowly in most biomes or habitats
    Puget Sound soils built from young glacial deposits, <10,000 yrs old, soils 1-3 feet thick (1 m)
    Brazilian rainforest soils, much older, up to 100 m thick (very high leaching bc of high rainfall)
    devegetation or deforestation: has several negative impacts on soils
         --cut off supply of organic material, change soil chemistry and processes radically
        --expose loose soil to erosion by wind, rainsplash, sheet wash, gulleying, etc.
         --expose soil to drying: tropical soils turn to brick, difficult to revegetate

Soil and Agriculture:  natural ecosystems displaced by non-native food crops worldwide
     cultivation of soil with alien plants must have many impacts on soil as a complex system
     cultivation of soil also affects soil erosion (loss of soil) and soil exhaustion (loss of productivity)
        minimizing soil loss:  tillage, alley and strip cropping, windbreaks/shelterbelts
        minimizing soil exhaustion: natural fertilizers, intercropping, polyvarietals, polyculture

"Pest"icides and Agriculture: insecticides, herbicides, fungicides, etc.
    typically complex chemical compounds, both organic (carbon based) and inorganic
        ex:  Lindane = chlorinated hydrocarbon, broad spectrum (kills many), persistent insecticide
    biological amplification:  persistent pesticide passed on up the food chain/web
        ex:  DDT concentrated 10,000 times more in birds than zooplankton
    pros and cons\:  productivity, profit vs biota destruction, pollution, genetic hardening
    risk assessment of pesticides:  malnourishment from lack of food vs. cancer rate

Food Production and Distribution:  the food might be there, but not well distributed
    Industrialized Agriculture:  requires large amounts of energy, water, fertilizer, pesticides, etc.
       monocultures of producers (grains, e.g.) or large-bodied consumers (cows, etc.)
        requires enormous harvest, storage, process and transport network (economy of scale)
        extremely high productivity as a result of high energy and resource usage
        natural resources finite, Industrialized Agriculture is non-sustainable; also highly pollutant
    Plantation Agriculture:  monocultural value-added cash crops (coffee, fruits, drugs, etc.)
        mini version of Industrialized Agriculture also requires huge farm-to-market infrastructure
    Subsistence Agriculture: local/individual consumption only, mix of crops and livestock
    Gatherers/Foragers/Hunters:  non-agricultural approach to subsistence.  a tough way to live

Fisheries:  80% of commercial catch from nearshore oceans, 20% from lakes and rivers
    much of catch not eaten directly, converted to food for other consumers
    what levels of catches/harvests are sustainable in highly dynamic aquatic habitats?
    factory trawlers:  catch+process on site.  very high extraneous bycatch (often wasted)
    aquaculture: farming (isolated from nature), ranching (temporarily), manipulation
 

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