Chapter 4 Flashcards
Why does agricultural diversity matter?
Cost-effective pest and disease management
Options to manage climate risks
Contributes to health and nutrition
Plays a role in sustaining soil health and habitats for important pollinators
How are people casual agents?
Population pressures
Poor management of agricultural land
When is land considered degradated?
When it’s productivity is diminished
What effects does degradation have on soil?
Soil erosion (serious)
Decreased soil fertility
Contamination (e.g. pesticides)
Salinization
What effects by does degradation have on land?
Overgrazing by livestock
Deforestation/Desertification
What happens when geological erosion occurs?
Geological erosion is a natural leveling process
New soil forms faster than old soil can be removed
What is accelerated erosion?
Erosion caused by water or wind
Which type of erosion is more destructive?
Accelerated erosion
10 to 100 times more destructive than geological erosion
What are some on-site effects of erosion?
Loss of topsoil
Washing away of seeds
What are some off-site effects of erosion?
Sediment damage to water
Windblown dust
What is the Universal soil loss equation?
A = Rainfall erosivity + Soil erodibility + Topographic Factor +Cover and management + erosion control practices A = RKLSCP
What are riparian buffer strips?
Natural or planted species along the bank of a stream or lake, reduces water velocity(erosion)
Name 3 Best Management Practices
Conservation Tillage
Riparian Buffer Strips
Cover crops and mulch
What are some soil conservation practices?
Contour farming
Contour buffer strips
Terrances
Contour stripping
Name 3 factors that affect wind erosion
Wind velocity and turbulence Soil surface conditions Roughness Moisture content Aggregate stability Texture Vegetation
What are some wind erosion control measures?
Soil moisture control
Conservation tillage
Barriers (windbreaks, grasses, fences)
How much of the Earth’s water is freshwater?
3%
Define eutrophication
Enrichment of water with nutrients
This happens when fertilizers end up in the water supply
Define anoxia
Absence of oxygen
What are the most important limiting nutrients for aquatic systems?
Nitrogen and Phosphorous
What is the cause of an ocean dead zone?
When the algae die their decay consumes a large amount of oxygen from the water and this leads to oxygen depletion or anoxia
What is a leading contributor to reduced water quality
soil erosion
What is the grasshopper effect?
Volatile substances move north by a series of ops
Multiple cycles of evaporation and condensation
What characteristics should the ideal pesticide have?
- Selective
- Biodegradable
- Non-persistent
- Non-mobile
Name 6 Greenhouse gasses.
Carbon dioxide Methane Nitrous Oxide Water Chlorofluocarbons Ozone
What do GHG’s do?
Absorb outgoing infrared radiation and warm the atmosphere
What are some positive impacts of climate change on agriculture?
Increased productivity
Possibility of growing new crops
Larger growing seasons
Decreased moisture stress
What are some negative impacts of climate change on agriculture?
Increased insect infections
Crop damage from extreme heat
Planning problems due to less reliable forecasts
Increased soil erosion
Decreased herbicide and pesticide efficiency
Increased moisture stress
Greenhouse gas emissions per kg of food are highest for:
Lamb
This gas is NOT a greenhouse gas but it negatively affects air quality and is particularly associated with agriculture:
NH3
More than half of the total emissions of this greenhouse gas come from the agricultural sector:
N20
Agricultural biodiversity is important because it can potentially provide farmers with a way to manage pests and diseases.
True
In the Universal Soil Loss Equation, C is related to:
Crop Type
In the Universal Soil Loss Equation, K is related to:
Soil organic matter
Riparian buffer strips can lead to increased eutrophication problems
False
The agricultural sector is the single largest contributor to total water USE in Canada.
False
The process(es) by which pesticides end up in the far north is related to:
a) Volatility of the pesticide
b) Selectivity of the pesticide
c) Mode of action of the pesticide
d) Persistence of the pesticide
e) Two of the above
E - two of the above
Greenhouse gases absorb incoming short wave radiation from the sun.
False
The earth would be _______________ without the presence of greenhouse gases in the atmosphere.
33oC colder
The following is NOT considered to be a potential climate change impact to Canadian agriculture.
a) Decreased productivity from enhanced CO2
b) Increased productivity from warmer temperatures
c) Increased insect infestations
d) Increased soil erosion
e) Increased droughts
A - decreased productivity from enhance CO2
Intraspecific biodiversity can help a crop withstand environmental pressures like drought or pests.
True
Which of the following animal products consumes the most water (on a per pound basis)?
Beef
This greenhouse gas is also responsible for destroying the ozone layer:
CFCs
