People, Agriculture, and the Environment

Exploitation

Use of a renewable resource without regard to long term productivity

Conservation

Use of a renewable resource within biological limits (maximum sustainable yield)

Preservation

Setting aside land for non-use or non-consumptive use, Yellowstone model

What is the link between agriculture and ideas concerning exploitation, conservation and preservation?

Land-sparing argument (intensive exploitation in some areas to preserve other areas), ag matrix argument (more complex landscape, land bridges, biodiversity, full conservation)

Importance of biodiversity

Integrity of ecosystems (more biodiverse ecosystems are more resilient, redundancy/backups), medical uses (45% of pharmaceuticals have at least on natural ingredient), ecotourism, extractive resources (e.g., rubber tapping), intrinsic value, aesthetic value

Top causes of biodiversity loss

Habitat loss and fragmentation (particular problem for large carnivores that range), exotic species (most will perish in strong ecosystems), hunting

Brief history of environmentalism in US

First wave in 1900-1910 ("turn of the century movement") realized after Civil War (and "cowboy economics") that resources were finite and focused on "green issues", 2nd wave in 1930s in response to Dust Bowl recognized soil as an important resource (FDR set up Soil Conservation Service), 60s/70s focused on brown pollution (EPA created, "Silent Spring") and recognized downside of economic growth, 80s/90s focused on sustainable development, 2000s-present narrower focus on climate change and energy efficiency

Trophic level

You lose 90% of useable energy each level you go up, argument for vegetarianism

Crops and animals the global population relies on for most of its food supply

15 plants (rice, wheat, corn, potatoes, etc.) and 8 animals (cows, pigs, chickens, etc.) supply 90% of world food supply

1st agricultural revolution

Transition from hunting and gathering to crop farming, first happened in the Fertile Crescent 10k years ago (happened at different times), trash heap theory

2nd agricultural revolution

Transition from extensive to intensive organic agriculture in response to population pressure

3rd agricultural revolution

Fossil fuels, nitrogen fertilizer synthesizing, industrial agriculture, Green Revolution

Shifting cultivation

Also called swidden or slash and burn, rational with limited labor and abundance of land, returns nutrients to soil, fallow for 20-40 years afterwards

Intensive subsistence agriculture

Population increasing, fallow decreasing, applying fertilizer and compost, intercropping/polyculture, agroforestry, tillage

Pastoralism

Animal husbandry, moving with the rains, governments don't like them (discrimination, sedentarization efforts)

Systems of industrial/commercial agriculture

High external inputs (fossil fuels, water, hybrid and GMO seeds, inorganic fertilizers and pesticides), 25% of global farmland

Milk shed

Before refrigeration, you had to have dairy farms around every city

Von Thunen's model and the pattern of commercial agriculture around cities

Before refrigeration, there was a model that showed what perishable crops are grown where in circles around cities, higher transportation costs further outside the city

Green Revolution

Response to increasing hunger/famine in 50s/60s, brought industrial agriculture to the Global South, Norman Borlog, called Green Revolution because US was worried about social unrest and communism

Pros and cons of the Green Revolution

Increased food production by 75%, but didn't resolve hunger, increased wealth inequality, farmer suicides, caused environmental problems (pesticide resistance, dams), bypassed Africa

Natural enemy hypothesis

More carnivorous insects in polyculture makes it more manageable

Resource concentration hypothesis

Herbivores more likely to find and remain on hosts in monocultures

Plant competition vs. facilitation

Competition is when plants compete for resources, facilitation is when one benefits the other

Soil erosion and declining soil fertility

Reducing fallow periods as agriculture becomes more intensive, inadequate supply of organic fertilizers, increasing cash crop production, changing grazing patterns, loss of traditional soil conservation practices, hillside erosion

Why has pesticide use increased in the Global South?

Cheaper, labor shortages, switching from polyculture to monoculture, increasing production, progress narratives

What factors help us understand why women farmers use more herbicides than in the past?

Household level (women's limited control over labor), regional scale (labor siphoned by artisanal gold mining), international scale (rise of generic herbicide production in India and China has made it more affordable)

Broad spectrum pesticides

Not specific to one pest, kill various insects, including natural enemies

Chemical persistence

Chemicals that do not degrade easily are more likely to cause long-term effects

Bioaccumulation

Small amounts of chemicals accumulating in organisms

Biomagnification

Chemicals moving up the food chain and magnifying as predators eat prey

Pesticide resistance

A few insects surviving and breeding with resistant traits

Pesticide treadmill

As pesticide resistance increases, farmers have to use more to get the same results

Circle of poison

Chemicals banned in the US but exported to other countries, then imports come back with chemical residues

Groundwater contamination

Fertilizer runoff, pesticides, repeated exposure over time, tiling (plastic tubes used to drain water speeding up runoff)

Salinization

From flooding irrigation, water evaporates and leaves salt behind, destroying the soil, very expensive to reverse

Non-point source pollution

Widely dispersed, smaller amounts that cumulatively add up to a lot, eg. agricultural runoff

Wind erosion

If you don't have enough surface vegetation

Water erosion

Sheet erosion is sheets of water, rill erosion is what creates gullies on hilly topography

Pros of no-till, conservation tillage

Reduced erosion (wind and water), maintain organic soil matter

Cons of no-till, conservation tillage

Used with herbicides (because tilling is used to get rid of weeds), doesn't work as well in cooler climates (because tilling is used to warm up the soil), GMO stalks not breaking down

Crop rotation

To avoid disease buildup and not use up nutrients

Strip cropping

Kind of like polyculture, can be a form of crop rotation

Contour plowing

Creating ridges to prevent erosion

Drip irrigation

More efficient than pivot irrigation, useful in drier areas, increasing use in horticulture with perennials

Rock lines

To stop sheet erosion

Gully plugs

To stop rill erosion

Parkland agroforestry

Trees intermixed with crops, increased soil fertility, shade, can provide economic benefits

Alley cropping

Rows of trees or shrubs to create barrier, crops in between

Windbreaks

For wind erosion

Shelterbelts

Creating habitats for animals to then hunt them

Organic fertilizers

Animal manure, green manure (manure made out of plants, leaves, or cover crops that are ground up into the soil), compost

Integrated Pest Management (IPM)

Using multiple methods of pest control, biological (using carnivorous insects), mechanical (nets, fans, scarecrows, etc.), chemical

Conservation buffers

Vegetative barriers around bodies of water to slow down runoff

Energy efficiency of modern vs. traditional agriculture

Modern industrial agriculture more productive but less efficient

Pros of genetic engineering of agricultural crops

Virus-resistance, Bt crops (pesticides), herbicide-tolerance, biofortification (vitamins), flood-resistance, more efficient, climate adaptation

Cons of genetic engineering of agricultural crops

Too expensive for the poor (recurring expense), maximizing production rather than minimizing risk, commodity crops (connections to global markets), inequality, profit-driven, apolitical, knowledge-enclosure, gene escape

Measuring agricultural sustainability

Farm level scale (water quality, nutrient, loss of organic matter, erosion), ecosystem scale (carbon emissions, pollution)