GEI Exam 4 Flashcards
Lectures 13-17
When did agricultural revolution begin?
10,000 years ago
humans select crop varieties and domesticate animals
artificial selection
What foods do we eat?
dozen types of grass (mostly rice, wheat, corn, and oats)
3 root crops (potatoes, sweet potatoes, cassava)
20 or so fruits and vegetables
6 mammals (cow, pig, goat, sheep, deer, rabbit)
3 domestic fowl (duck, chicken, turkey)
few fish species
What crops are grown the most in the U.S. and for what?
corn and soybeans (mostly livestock feed)
How have yields changed in the last 100 years?
increased (ex. corn in 1900: 25 bushels/acre vs corn today: 200)
How yields were increased in past years
chem. fertilizers, plant breeding, pesticides, irrigation, mechanization, large-scale farms, gov. subsidies, and high density livestock
types of pesticides
insecticides, herbicides, fungicides, and rodenticide
most common herbicide in U.S.
Glyphosate (Roundup)
crops genetically modified to resist glyphosate
Roundup-ready
negative impacts of roundup-ready crops
water pollution, bioaccumulation, pesticide resistance, impacts on beneficial insects, human health risks, food residues
major inorganic nutrients in fertilizers
nitrogen, phosphorus, potassium
uses about 70% of all freshwater in U.S.
irrigation
methods of irrigation
center-pivot, drip, flood
negatives of irrigation
erosion, water scarcity, evaporation loss, fuel use
negatives of mechanization
soil erosion, fossil fuel use
erosion
movement of soil particles by wind or water
forms channels and ravines in farmland
gully erosion
livestock trample vegetation as they drink from streams
streambank erosion
removes soil where plant cover is gone due to drought or overgrazing
wind erosion
fed government provides payments for farmers to produce certain goods (low-price crops)
government subsidies
animals confined in high densities and fed high calorie diets
high-density livestock
prevents illness from overcrowding in HD livestock
antibiotics
areas in the U.S. with limited access to nutritious, affordable food
food desert
promoting biodiversity, soil health, and water conversation (reduce pesticides and synthetic fertilizers)
sustainable ag
alternative to chem pesticides
growing 2 crops at the same time in alternating rows
intercropping
seasonally alternating crops
crop rotation
use of natural enemies to control pest populations
biological control
pro: reduce soil erosion, protect soil organisms, reduce evaporation, slows organic decomp.
con: requires more herbicides
pros and cons of no-till
lines of trees or shrubs that acts as windbreaks
shelterbelts
plowing across a hill rather than up and down
contour plowing
e.g. native grasses or legumes
protect soil from water and wind erosion
cover crops
legumes that convert atmospheric N to usable through root nodules with bacteria
nitrogen-fixing crops
e.g. “3 sisters” (corn, beans, squash)
companion planting
plants, animals, or microbes that have had their DNA modified to produce a certain trait (aka biotech or genetic engineering)
GMOS
DNA comes from unrelated organism to produce desired trait
transgenic
higher yields, drought resistance, enhanced nutrition, resistance to pathogens, longer shelf-life, livestock grow faster or produce more
benefits of GMO
bacteria used to give plants ability to produce insecticide
Bacillus thuringiensis
health risks from GMOS are
negligible
biggest biotech company in the world (patents)
Monsanto (Bayer owned)
coal, oil, natural gas, nuclear
non-renewable energy
solar, wind, hydroelectric, and biomass
renewable energy
4 major sectors that consume energy
industrial, transportation, residential, commercial
amount of energy that comes from fossil fuels in the U.S. (2015)
80%
