Unit 3 Flashcards
What is polyculture
Different crop types planted all year
What type of agriculture does slash and burn
Traditional agriculture
What are subsidies
Tax to farmers
What type of agriculture is monocultural
Plantation agriculture
Organic agriculture uses:
No pesticides or fertilizers
Animals eat organic
What is a CAFO
Contained animal feeding operation
Green Revolution def
A time when farming practices switched in order to produce more food for an increasing population
Soil def
Mix of geologic and organic components
Humus def
Decomposed organic material
Has lots of nutrients
What are the layers of soil
O
A
B
C
What is the O soil layer
All organic material
Decomposed leaves/plants
What is the A soil layer
Topsoil
Minerals from below with organic material
Where roots are
What is the B soil layer
Subsoil
High in minerals but low in organic material
Clay
What is the C soil layer
Weathered bedrock
What differentiates soil texture
Particle sizes
Soils with the biggest particles to smallest particles
Sand- biggest
Silt
Clay- smallest
Smaller particles = ______ porosity
Higher
Smaller particles = ______ permeability
Lower
Photosynthesis reactants
CO2, H2O, and sun energy
Photosynthesis products
O2 and glucose
Cellular respiration reactants
O2 and glucose
Cellular respiration products
CO2, H20, energy- ATP
Where is most of the carbon on earth
Ocean
Where is most of the nitrogen on earth
Atmosphere
What gas in the atmosphere has triple bonds and can’t be used by living organisms
N2
What is the formula for nitrate
NO3
What is the formula for nitrite
NO2
What is the formula for ammonia
NH3
What is the formula for ammonium
NH4
What can soil bacteria turn excess nitrates into
N2O, nitrous oxide
What is fixation in the nitrogen cycle
Nitrogen gas from the atmosphere is turned into nitrates from lightning/fires and ammonia from nitrogen-fixing bacteria
N2 —> NO3 or NH3
What is assimilation in the nitrogen cycle
An organism takes in a nutrient, like a plant taking in ammonia
What is nitrification in the nitrogen cycle
Bacteria oxidize NH4 adding oxygens to it. First forming nitrite and finally forming nitrate
What is ammonification in the nitrogen cycle
Decomposers make ammonia
Organic forms of nitrogen into ammonia
What is denitrification in the nitrogen cycle
Nitrates lose their oxygen atoms and are converted back into N2 in the atmosphere
Why is phosphorus cycle unique
Doesnt go into the atmosphere or a gas
What cycle is the slowest
Phosphorus
What is the largest reservoir for phosphorus
Sedimentary rock
What is no-till farming
Old plants are cut but their roots are left in the soil. Then new plants are planted on top
What is agroforestry
Incorporates trees so plants can grow in the shade
Coffee
What is cover crop
Planting crops over other crops
What are windbreaks
Rows of trees and plants infront of crops
What is contour farming
Follows the slope of land to prevent erosion
What is green manure
Growing specific crops that are then plowed back into the soil
What is a pest
Any species that interers with human welfare
What are chemical pesticides
Compounds used to intentionally reduce pest populations
What are first generation pesticides
Highly toxic for wide range of organisms.
Before 1940
Naturally occurring
What are inorganic compounds
Dont break down in soil or water (persistence)
What are organic compounds
Plant-derived compounds
What are second generation pesticides
Synthetic chemicals produced in a lab
After 1940
What are broad spectrum pesticides
Toxic to a wide range of species.
Eliminates natural predators that keep the population in check
What are narrow spectrum pesticides
Designed to control a select group of pests. With hormones or physical characteristics
What is bioaccumulation
Increase in chemical concentration within one organism over time
What is biomagnification
Increase in chemical concentration as its passed through food chains
What is a pesticide treadmill
Forced to use larger amount and more toxic chemicals as the pests evolve resistance
What is the clean water act
Laws designed to fight water pollution.
Only surface water
Permit system
What is the safe drinking water act
Laws setting national standards for safe drinking water
EPA establishes maximum contaminant levels
Groundwater applies
What is biological pest control
Biological, ecological, or cultivation tools to reduce pest populations
What is integrated pest management
Program evaluating each crop and pest as part of an ecosystem. Reduce crop damage with minimum pesticide use
What is selective breeding
A form of artificial selection that has been used for millennia to produce crops and livestock with preferred traits.
What are GMOs?
Organisms that have had their DNA altered by genetic engineering
What percentage of annual water consumption is agriculture responsible for
70
What is flood irrigation
Let water flow and disperse over a field surface
Need a slope
What is furrow irrigation
Let water flow and disperse through trenches
Extreme evaporation loss
What is spray irrigation
Pump groundwater into sprinklers to distribute water from central location.
Nozzles clog
Machinery
What is drip irrigation
Delivers water directly to plant through small pores in pipes
What is an aqueduct
A cement base trail for water to flow in
What is a dam
Controls flow of water
Produces hydroelectric power
Deprives downstream river of water
Flooding upstream
What is a LD50
Dosage that is lethal to 50% of test subjects
What is a LC50
Concentration of solution that is lethal to 50% of test subjects
What is a threshold dose
Dosage at which the effect is first observed
