soil, agriculture, meat, and fish enviro study guide
Bedrock: solid rock composing the Earth’s crust
Leaching: removal of minerals by water (E horizon is the most leached)
Hydroponics: growing plants without soil
Weathering: processes that form soil
physical/mechanical: formed by wind and rain
Chemical: soil is chemically altered
Biological: organisms produce soil through physical or chemical means
contour plowing: plowing perpendicular to a slope so that when it rains, water gets trapped and can’t flow downhill.
Aquaponics: A food production system that combines aquaculture with hydroponics (ex. The fish that get minerals for the plants and the plants clean the fish tank)
Erosion: gradually wearing away/degradation of the soil
strip cropping: crops that let water through and some crops that do not let water through.
Eutrophication: The environment becomes enriched with nutrients, which increases the amount of plant and algae growth.
Humus: organic content in soil (insoluble residue from partially decomposed plants and animals)
Composting: The process of recycling organic matter into something that can be used to enrich soil.
Irrigation: Application of controlled amounts of water to land to help grow crops and etc
Salinization: Increased salinity due to irrigation
no-till agriculture: Farmers do not till their fields, which minimizes soil disturbance.
Terracing: Making a hill into literal steps so water cannot flow down.
Desertification: A loss of more than 10% productivity
crop rotation: Alternating crops with legumes so N and P are naturally replaced.
Loam: A soil mixture of clay, silt, and sand
Compaction: collapse of air spaces in the soil
Fisheries and Meat Production Terminology:
Purse seine:
Large wall of netting deployed around fish that is pursed around bottom
Used to catch schooling fish (ex. tuna)
Low rate of bycatch compared to other commercial fishing methods
High yields of fish
trawl (bottom or midwater):
Fishing practice involving a large net on the seafloor to catch fish
Up to 90% bycatch
Damages habitats
Catches range from fish to shrimp and crabs
Bycatch
Catch of fish unintentionally/ unwanted that are not the target fish.
Longline
Involves one main long line that can extend several miles with smaller hooks attached
23% of global catch
Risks bycatch and habitat damage
Target fish include tuna and swordfish
gill net / drift net
Gill net used in shallow water
Drift net - fish get caught when they swim into it (it like hovers i think idk)
Habitat damage - damages seafloor
Has a lot of bycatch - Discard rate of 55%
Aquaculture
Farming of aquatic organisms for food, recreation, and other purposes.
Net pens/ open ocean systems
Tilapia, salmon, etc
cage free
Indoor only, no cages
Densely packed
pasture raised
Animals that have spent a portion of their life on the pasture.
Skills and Concepts:
1. What is the distinction between weathering and erosion?
Weathering is the decomposition of soils and their minerals and rocks. Erosion is the displacement of solids.
2. How is a soil triangle used?
Used to determine type of soil based on sand, silt, and clay percentages.
3. How are sand, silt, and clay different?
They have different particle sizes
4. What are soil horizons? What does the profile of soil look like (O, A, E, B, C)
O layer - organic matter - Leaf litter, partially decomposed organisms
A layer - Topsoil - mineral particles mixed with organic material
E layer - (LEACHED) eluviation - depleted of soluble materials
B layer - (Subsoil) Often dense texture from accumulation of nutrients.
C layer - (Parent material) Weathered rock fragments with little organic material
5. Why is soil porosity important?
6. How can we reduce soil loss by erosion?
7. Why are crops rotated? What do legumes have to do with it?
Crops are rotated in order to give the soil a break. Legumes naturally replace the nitrogen and phosphorus in the soil when they are rotated in.
8. Which three crops produce the greatest proportion of the world’s calories?
Wheat, corn, and rice.
9. Why is modern “industrial” agriculture not sustainable? (several reasons)
Industrial agriculture is not sustainable. Reasons:
Overfarming (soil degradation and loss of farmland)
Bad for environment (agriculture wastes a lot of water) (methane from cows)
10. How is hydroponics different from conventional agriculture?
Hydroponics is different from conventional agriculture because it uses no soil. It also uses way less water than conventional agriculture and less land. It is more sustainable.
11. What is “aquaponics?” What is the principle behind aquaponics that makes it so efficient?
Aquaponics uses both hydroponics and aquaculture. Hydroponics
12. How is “grass fed” beef different? Why is it more expensive?
It is more expensive because
13. Is commercial fishing in general sustainable? Are there some types of seafood production that are currently sustainable?
No it is not sustainable because there is overconsumption of the fish and destruction of habitat.
Alaskan salmon is sustainable because everything is controlled and it is monitored by scientists to prevent overfishing. There is also barely any bycatch.