ch 9, 10 broad overview

cropland covers ___ of earth’s surface

12%

rangeland covers ___ of earth’s surface

26%

soil degredation

loss of productive soil, resulted primarily from forest removal, agricultural practices, and overgrazing

subsistence agriculture

producing only enough food for the family farming the land

monoculture

large-scale, uniform planting of a single crop

green revolution

1950s, spread industrial agriculture techniques as practiced in developed nations to developing countries (mechanization), helped avoid mass starvation, but resulted in much soil degradation b/c monoculture, pesticides, and synthetic fertilizers

sustainable agriculture

characteristics that maintain healthy soil, clean water, pollinators and other resources needed for long-term crop and livestock production

soil by volume

50% mineral matter

5% organic matter, consists of microorganisms and decaying material

45% pore space taken up by air or water

parent material

base geological material, rock, or sediment of a particular location

soil formation

the slow physical, chemical, and biological weathering of parent material

soil horizons

O - litter layer, mostly organic matter

A - topsoil, some organic material and minerals

E - zone of leaching or eluviation, minerals and organic matter leave this horizon and move lower

B - subsoil, minerals and organic matter accumulate from above

C - largely weathered parent material

R - pure parent material

soil texture

determined by size of its particles from clay (smallest) to silt to sand (largest)

loam

even mixture of clay, silt, and sand

cation exchange capacity (CEC)

process by which plants’ roots donate hydrogen ions to the soil in exchange for cations of nutritional value like calcium, magnesium, and potassium. CEC also called nutrient holding capacity

clayey soil

waterlogged soil, roots deprived of oxygen

acidic, low pH soils have a ___ CEC

low

land degredation

the deterioration that diminishes land’s productivity and biodiversity

erosion

the removal or material from one place and its transport to another by wind or water. major causes include excessive tilling, overgrazing, and forest removal

desertification

more than 10% of land productivity is lost due to erosion, soil compaction, water depletion, salinization, etc.

contour farming

plowing sideways furrows across a hillside to reduce runoff

terracing

level platforms that are cut into hillsides to contain water, common with rice crops

salinization

salt contained in irrigation water becomes concentrated on soil surface due to high evaporation rates

Conservation Reserve Program

1985, pays farmers to stop cultivating highly erodible cropland and conserve it instead

energy subsidy

energy input per calorie of food produced

highest to lowest input for 1kg of product

beef

pork

eggs

chicken

milk

___ of global grain production goes to livestock

45%

colony collapse disorder

the phenomenon that occurs when the majority of worker bees in a colony disappear and leave behind a queen

neonicotinoids

a new class of chemical insecticides. become systemic in the plant, ending up in all parts of the plant. ultamitely make the plant toxc to insects, killing them if they try to feed off of or pollinate the plant

pestcide treadmill

pests evolve to be resistant to pesticides, so we have to make them more toxic, they evolve again, etc.

bacillus thuringiensis (Bt)

naturally occuring soil bacterium that produces a toxin that kills bugs. can be sprayed on crops to protext them from insects

integrated pest management (IPM)

multiple techniques including biocontrol, use of limited chemicals, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal

biocontol can go wrong when ____

the biocontrol agent becomes a pest itself or have unintended effects in an area where it’s not native and has no predators

organic agriculture

no chemicals! uses biological apporaches to pest contrl like biocontrol and composting

organic agriculture takes up less than __ of land worldwide

1%

crop yields of organic agriculture are about ___ of industrial

80%

GMOs

organisms that have been genetically engineered using recombinant DNA, which is DNA that has been spliced together from multiple organisms

transgenic organisms

contain DNA from another species. includes all GM species

in the US ___ of corn, soybeans, cotton, and canola consist of GM strains

90%

___ of processed foods in the US contain GM ingredients

70%

critics of GM crops (pg 111 prep book)

environmental, health, ethical concerns

supportors of GM crops (pg 112 prep book)

environmental and economic benefits

precautionary principle

one should not undertake a new action until the ramifications of that actions are fully understood

Organic Food Production Act

1990, established national standard for organic products in the US

logically grown agriculture

reduces fossil fuel consumption for transport

standards for organic agriculture

idk look it up