APES - Unit 5 - Earth, Soil, Food & Agriculture

Core

innermost layer of earth, hot dense mass of nickel + iron

Mantle

layer above the core, contains molten rock (magma) that slowly circulates by convection

Asthenosphere

layer of the mantle, composed of semi-molten flexible rock

Lithosphere

earths crust and the outermost layer of the mantle - contains the tectonic plates

Hot Spots

area where molten material from the mantle rises to the surface (lithosphere) NOT at a tectonic plate boundary - creates chains of volcanic islands - mantle convection currents

Plate Tectonics

theory that earths lithosphere is divided into large plates in constant slow motion

Seafloor Spreading

process where magma pushes up and out creating new oceanic crust - forms mid ocean ridges - expands the ocean floor - brings up copper, lead and silver

Subduction

process where one tectonic plate slides beneath another and is destroyed - denser oceanic crust sinks beneath less dense continental crust

Divergent Plate Boundary

plate boundary where plates move apart - creates rift valleys (continental plates separate) and mid ocean range (oceanic plates)

Convergent Plate Boundary

plate boundary where plates collide - creates subduction zone - trenches form at intersection - volcanoes form on other side from heat and pressure of melting plates

Transform Fault Boundary

plate boundary where plates slide past each other horizontally with great friction - causes earthquakes - rocks resist motion util pressure too high then they slip quickly

Soil

relatively thin layer of earths crust - need it to

1. grow food

2. decompose

3. filter/absorb water

4. give habitat to organisms

Soil formation

formed by many factors including parent material, weather, temperature, geography, age, and the organisms that live in it - consumers in soil react with water to make carbonic acid

Soil Horizons

O - organic matter - living things and detritus

A - topsoil - dark & nutrient rich - essential/ bad if eroded

B - subsoil - materials that leach through A (iron/clay rich) - supports roots

C - parent material - partially weathered - now vacant

Soil texture

categorized by 3 particle types (from big to small) - sand - silt - clay — affects amount of water, air, mineral nutrients, pollutants and root abundance

sandy soil

soil drains quickly and dries out easily - easy for root penetrations bc of loose pack but nutrients lost through leaaching

clay soil

soil packs together tightly - limited space - water and root cannot move or get in easily

Essential Mineral Nutrients

(N)itrogen, (P)hosphorus & (K)Potassium

Cation Exchange Capacity

Nutrient holding capacity - ability of a soil to attract (absorb ions) - how many negatively charges sites are available in a soil to attract positively charges minerals (NPK)

Soil pH

Typically acidic soils have low nutrient holding capacity - more basic means more nutrients available for plants - 6-7pH is ideal

Ideal Soil Type

Loam - 40 sand, 40 silt, 20 clay - large particles allow air and structure - small particles allow minerals and water

Soil degradation

loss of some or all of the ability of a soil to support plant growth - from agricultural overuse, forestry and soil erosion

Minerals

solid chemical substances with uniform structures, formed under specific temps/pressures - many are metals (copper, iron, aluminum, gold, lead) - some nonmetal (gravel, granite, clay, quartz, sand, salt)

Ore

concentrated accumulations of minerals from which economically valuable materials can be extracted (small amounts in crustal rock - bauxite of aluminum)

Reserves

known quantity of a resource that can be economically recovered - not yet extracted

Most Common Elements in Earth’s Crust

oxygen, silicon, aluminum, and iron

Sub Surface Mining

mining - vertical shafts, elevators, and tunnels underground - majority for coal (electricity), diamonds & gold

Problems:

1. Acid Mine Drainage (acidic water pumped out pollutes)

2. Unstable and known to collapse

3. Respiratory Diseases (black lung, lung cancer)

4. significant fossil fuel usage for equipment

5. contamination by tailings

Types of Surface Mining

• Strip Mining

• Open Pit Mining

• Mountain Top Removal

• Placer Mining

Problems of Surface Mining

1. air pollution from equipment creating dust

2. contamination of water thru tailings

3. lacking reclamation - soil erosion

4. habitat alteration/fragmentation/destruction

Mine Reclamation

SMCRA: Surface Mining Control and Reclamation Act - coal mining regs, mandated land be returned to a minimally disturbed state - fill in with non contaminated material and shape and replant to fit original topography - return topsoil

Food In/Security

access to sufficient, safe and nutritious food that meets dietary needs for a active/healthy life or lack thereof bc of socio-economic issues

Undernutrition/Malnutrition

not enough calories or not the necessary balance of carbs, proteins, vitamins, etc. (processed foods) - caused by war/conflict, poverty/accessibility, food waste and agricultural resources (grain being fed to livestock instead of people)

Anemia

iron deficiency - most widespread nutritional deficiency in the world

Energy Subsidy

energy input per 1 calorie of food - use way more energy than we get - higher in developed countries

Meat Consumption

40% of grain goes to feeding livestock - takes many more resources than vegetables or grains (10% rule) - increased wealth linked to higher consumption

US Food Footprint

higher than most countries - energy subsidy 10 (inefficient) - wealth and meat consumption linked - accustomed to accessing all types of food no matter the season (imports)

Green Revolution

agribusiness - mechanization and standardization of the production of food - use of fertilizers, pesticides, irrigation and monocropping and GMOs

Mechanization

using powered machinery to increase agr productivity and lower lost - contributes of Economies of Scale (more production means decreased price per unit - more profit)

problems: small farms out competed - growth of monocropping

Monocropping

planting only one crop to maximize efficiency and specialization - only need one type of machinery/pesticides/fertilizers

problems: can be wiped out (soil erosion/ nutrient depletion) - huge areas exposed at once → erosion of soil horizon - attracts only one pest bc of unlimited food supply → competition and predators nonexistent

Fertilizer

substances that add essential nutrients to soil/plants

• Synthetic: convenient, suited to crop - takes lots of energy to produce - leads to water pollution → eutrophication

• Organic: natural → less greenhouse gases - improves water holding capacity - slower and smellier - not specially suited nutrients

irrigation

artificial application of water to support crop growth - used to grow crops in arid locations - uses huge amounts of water

Problems: sinkholes, waterlogging (roots drown) and soil salinization (salt in groundwater accumulates then poisons)

Pesticides

substances used to kill / repel / control organisms like pests, insects, weeds or fungi - increase crop yield - include active ingredient (glyphosate) and inert that corps dont disclose - regulated under FIFRA (federal insect/fungi/rodenticide act)

Pesticide Problems

• possible carcinogen (exposure amount)

• pollutant in majority of groundwater

• links to antibiotic resistance, kidney disease, neurological disorders and hormone disruption

• manipulation of regulatory processes

• biodiversity loss (especially pollinators)

• persistent bioaccumulates

Pesticide Treadmill

when pests build up tolerance and resistance to the pesticide and grow in abundance → eventually pesticide is ineffective

GMOs

genetically modified organisms - gene copied into an organism that it then passes on

GMO Pros

• improved food security

• higher crop yields

• reduced pesticide use

• not manufactured - reduce greenhouse gases

• lower price - higher accessibility

• no proven health risk

GMO Cons

• gene outcrossing - copied gene dominates wildlife

• loss of biodiversity

• Herbicide health concerns

• unknown long term effects

• public transparency issues

• highly processed foods not always labeled

• Labeling rules could help corps conceal use

Shifting Agriculture

clearing land and using it for only a few years until the soil is depleted of nutrients - slash and burn to reest. fertility

Desertification

when usable land becomes unusable → turns into a desert - result of deforestation, overgrazing and/or erosion - dry areas prone

Nomadic Grazing

leading herds of animals to seasonal fields of crops → land fertilized by animal manure → vegetation regenerates - the only sustainable way to use low productivity soil

3 Major Farming Issues

1. soil erosion

2. mineral depletion

3. pest management

Reduced Tilling farming

leaving previous crop residue on the soil and leaving the soil undisturbed - helps soil erosion and mineral depletion also saves money bc dont need fertilizer - could require dif types of machinery/herbicides

Crop Rotation

give and take of variety by rotating crops every season/year - reduced fertilizer and pesticide use - dif size plant/roots could help prevent soil erosion

Agroforestry

shelterbelts - intercropping trees with crops

Pros: allows veg of dif heights (less soil erosion) and can provide shade, shelter for pest predators, and fruit that could add nutrients to soil

Cons: tree roots complicate irrigation, herbicides can harm trees, could take sun/water/nutrients from the crop

Contour Plowing

planting and plowing according to the lands topography - uses terracing to counter steep slopes - reduces water loss and soil erosion

Strip Cropping

intercropping - alternating strips of different crops - promote synergistic interaction - dif size plants helps reduce soil erosion - use dif minerals (less mineral depletion) and attract dif pests so predators come

Integrated Pest Management

IPM - using a variety of sustainable techniques that minimize pests and the need for pesticides - could require new equipment

Organic Farming

the minimal use of pesticides - no synthetic fertilizers - no animal antibiotics or growth hormones - no GMOs or genetic engineering in animals or feed - no confined animals - 70+% of ingredients organic

Organic Pros

• no synthetic fertilizer → less water pollution

• no pesticides → no loss of biodiversity or health risks

• No GMOs health risks

• Less E.coli and antibiotic resistance

• No bacteria or salmonella from CAFOs

Organic Cons

• GMOs could end up in crops

• potentially less nutritious (Golden Rice)

• expensive - more land - new equipment

• pass on price to consumer

• less efficient while population rapidly growing

CAFOs

Feedlots - concentrated animal feeding operations - less land → more efficient

Problems:

• enormous amount of manure → eutrophication

• Crop feed → high energy subsidy

• Corn → E.coli contamination from manure

• Antibiotic resistance in bacteria

• unethical conditions

Overfishing

catching fish faster than they can reproduce, leading to population collapse and ecosystem damage

maximum sustainable fishing yield

The largest amount of fish that can be harvested indefinitely from a population without reducing the population’s long-term size, usually occurring at about half the carrying capacity

Fishery Collapse

When a fish population declines so drastically (90+%) that it can no longer support commercial fishing, often due to overfishing, poor management, or habitat damage.

Bottom Trawling

Large weighted nets dragged along the ocean floor to catch ground-dwelling species.

Problems:

• Destroys seafloor habitats (coral reefs, benthic ecosystems)

• High bycatch

• Resuspends sediments, harming water quality

Long Line Fishing

Miles-long lines with thousands of baited hooks used to catch species like tuna and swordfish.

Problems:

• High bycatch of seabirds, sea turtles, and sharks

• Can severely reduce predator populations

Gill Net Fishing

Vertical panels of netting that trap fish by their gills.

Problems:

• Nonselective → high bycatch

• “Ghost fishing” when lost nets continue catching organisms

Purse Seines Fishing

Large nets encircle schools of fish and are drawn closed at the bottom.

Problems:

• Bycatch of juvenile fish, dolphins, and turtles

• Can deplete entire schools quickly

Bycatch

The unintentional capture of non-target species (e.g., dolphins, turtles, seabirds) during fishing, often resulting in injury or death.

Aquaculture

The farming of aquatic organisms (fish, shellfish, algae) in controlled environments.

Methods

• Fish ponds

• Ocean net pens

• Raceways

• Integrated multitrophic aquaculture (IMTA)

Aquaculture benefits

• Reduces pressure on wild fish populations

• Produces high yields of protein

• Can be more efficient than wild fishing

Aquaculture Problems

• Water pollution from waste and excess feed

• Spread of diseases and parasites to wild fish

• Use of antibiotics and chemicals

• Habitat destruction (e.g., mangrove loss)

• Farmed fish may escape and compete with wild species