Soil and food production

Ring of Fire

volcanoes around Pacific plate

convergent boundaries

-plates pushed together by compressional force -ocean crust is underriding continental crust, subduction and collision

convergent ex:

sierra nevada mountains, african plate collide(not subduction), appalachian mountains(collide)

divergent boundaries

plates spread apart by tensional forces, can result in seafloor spreading, rift valleys, volcanoes and earthquakes

divergent ex

mid-atlantic ridge

seafloor spreading

processes associated with the formation of new areas of oceanic crust, occurs through upwelling of magma along mid-ocean ridges

rift valleys

depression with steep walls formed by downward displacement of block of the surface, pulling apart of continental crust

transform boundaries

sliding past each other, creating fault systems along plate margins

continental crust

thick part of the earth's crust that forms the large landmasses, older and more complex

oceanic crust

primarily composed of mafic rocks(rich in iron and magnesium) and more dense than rocks underlie continents, younger

transform ex

San Andreas Fault

what are mountains

actively forming and are dominated by rocks that have formed after the breakup of Pangea

island arcs

long chain of volcanoes formed along convergent boundaries

example of island arcs

japan, Aleutian islands in Alaska

what is a result of volcanoes

island arc

hotspots are \________ in the crust

thin spots

hotspot ex

Hawaiian hotspot, Yellowstone hotspot

hotspots

place in the upper mantle of the Earth at which extremely hot magma from lower mantle upwells to melt through crust

earthquake system

faults: crack

focus(hypocenter): movement

epicenter: right above the earthquake

\-p and s waves

earthquakes are..

friction along the subduction zone reveal that crust is slowly sinking back into the mantle

volcanoes are...

conical mountains having a crater/vent through which lava and rock fragments been erupted by earth's crust

soil is a mixture of...

eroded rock, mineral nutrients, decaying organic matter, water, air, living organisms (mostly decomposers)

faults are...

formed and remain active for long ages before becoming inactive, associated with volcanic regions

seismic waves

wave produced by an earthquake or large explosion

what is a tsunami

generated by subduction-zone-related earthquakes

metamorphic rocks

subjected to high heat pressure or fluids which change their form

igneous rocks

formed through cooling and solidification of magma or lava

sedimentary rocks

formed by accumulation or deposition of mineral by water or air

weathering

physical, chemical, or biological breakdown of rocks and minerals into smaller particles

erosion

mechanical process by which material is dissolved, loosened, or worn away from one part of the Earth's surface and deposited elsewhere by water, wind or glacial ice

weather produces \______ and erosion moves \____

sediments

physical weathering

involves all processes that collectively break rocks into smaller pieces

chemical weathering

involves the breakdown(decay, decomposition) of rock by chemical means

biological weathering

breakdown and movement of rock and soil caused by expanding tree roots, burrowing, feeding activity, etc.

mass wasting

rock and soil masses become detached to underlying material and move downhill under the influence of gravity

layers of soil

o layer, a layer(topsoil), e layer, b layer, c layer

O layer

the uppermost horizon of soil, primarily made up of organic material

humus: partially decomposed

A layer

topsoil, sand, silt, clay

organics leaching down

zone of leaching of soluble mineral components

E layer

light colored leaching, minerals

B layer

accumulation of clay/sand/silt, fine materials and mineral precipitates

C layer

partially altered parent material

what is the c layer in virginia

granite, in the mountains limestone

what biome doesn't have a rich o layer and why

tropical rainforest -doesn't have subsoil -plants take the nutrients and organic matter decomposes because of warm and wet environment

soils can be eroded by....

wind or water

protecting soils can protect...

water quality as soils affectively filter and clean water that moves through them

which biome has the deepest O layer?

coniferous forest, we have cold seasons

which biome has a deep A layer?

grasslands

texture

fine, medium and large -determine infiltration and porosity

infiltration

downward movement of water into soil

percolation

passage of water through spaces of a pore in soil leaching

leaching

dissolving of minerals and organic matter in upper layers carrying to lower layers, soil type determines degree of infiltration and leaching

grains make up \___ of world's food, wheat rice and corn

77%

\___ world survives off of developing vs developed

2/3

croplands make of \_____ of land area

11%

Rangeland makes up \_____ of total US land area

29%

meat makes up \______ of world's food

16%

seafood makes up \______ world's food(including agriculture)

7%

food

should support metabolic processes and give energy

1st Green Revolution

occurred in developed countries, US-1940s, elsewhere 1950s-1970

what did the 1st Green Revolution introduce?

1. scientifically bred/selected varieties of grain with large inputs of: pesticides, fertilizer, water

what were the results of the 1st green revolution

greatly increased crop yields, doubled crop production on the same amount of land -protecting vast areas of wilderness (more trees in VA more than 100 years ago)

2nd green revolution

occurred in developing countries; China, Japan Brazil in 1960s

what did the 2nd introduce?

1. Fast growing varieties of rice and wheat for sub/tropical climates
2. Allowed 2-3 crops per year

what were the results of 2nd?

312% increase in World Grain Production between 1950 and 2013 from 1st and 2nd, 37% per capita grain production increase between 1950-2014(18th ed.)

3rd Green Revolution

Gene Rev, expression of creativity

what did 3rd introduce?

genetically engineered crops and livestock, often involving gene species from other species, takes about half the time to create compared to traditional selective breeding(usually cost less, unlimited possibilities, US produced 70% of genetically modified crops, 2/3 of US food contains genetically ingredients)

how much gm crops does the US produce?

70%

\_____ of US food contains genetically modified ingredients

2/3

GM plants made resistant to...

heat

cold

herbicides

pesticides

parasites

pests

viral disease

drought

acidity

salinity

grow fast-orange tree that produces 1st instead of 6th year

Industrialized agriculture food production

use large amounts of... fossil fuels, water, commercial fertilizers, pesticides to produce monoculture and livestock

soils can be eroded by \_________

wind and water

Protecting soils can protect\_____

water quality and productivity

terracing

broad, nearly level shelves that run across contours of mountainous land

contour planting

plowing across the contour of gently sloping areas instead of plowing down the slope

wind breaks

line of trees that slow winds to help prevent soil erosion from wind

repeated irrigation can...

reduced crop yields by causing salt buildup in the soil and waterlogging of crop plants

salinization

*draws water out*


1. irrigation water contains small amounts of dissolved salts 2. Evaporation and transpiration leave salts behind 3. Salt buildup in soil

waterlogging

*can't carry out respiration*


1. Precipitation and irrigation water percolate downward 2. Water table rises 3. Occurs with flood/furrow irrigation

desertification

reduction in productivity to at least 10%

levels of desertification

desertification to 10%

moderate desertification to 25%

severe desertification to 50%

very severe desertification to 50%+

what would lead to desertification

losing soil, drought, disease

conventional tillage

turns the soil

how many farmers use conventional?

50%

conventional structure

soil structure: poor

erosion: high

water holding/infiltration: low

nutrient retention: low

conservation structure

soil structure: good

erosion: low

water holding/infiltration: high

nutrient retention: high

conservation tillage

reduces tillage intensity, improves soil structure by leaving crop(plant) residue(organic material) in place

advantages of conservation

creates O layer, help with infiltration-cover crop, reducing evaporation, release nutrients, reduce soil erosion, improve air quality by putting sediments in the air, improves soil, air, and water quality

special tiller open up the subsurface without\______

turning over topsoil (conservation)

seeds, fertilizer, and herbicides are injected into \_____

silts in the soil

strip cropping

alternating row crops such as corn and legumes(beans/clover, cover crop)

overgrazing

results when too many grazers feed too long in one area and exceed carrying capacity of grassland area

what does overgrazing cause?

1. reduced primary productivity desertification 2. reduced grass cover 3. increased erosion 4. soil compaction(decreases water holding ability-cow stand too long) 5. weed and shrub invasion

solution to overgrazing

rotational grazing- control number of animals grazing(move through paddocks)-limit duration of grazing

how to protect water quality(not soil)?

exclude cattle from natural streams with fencing and position water sources remotely -farms: non-point sources

largest human use of freshwater is for...

irrigation (70%)

different methods of irrigation

flood/furrow irrigation: 60-80% efficient, center pivot sprinklers: 80-95% efficient, drip irrigation: 90-95% efficient(prevent evaporation)

Ogallala Aquifer(geologic water-old water)

Largest aquifer in North America from Southern South Dakota to Texas, one of largest in the world

Dry land farming

stop farming water thirsty crops like corn in semiarid climates and plant wheat, grain sorghum, sunflower and genetically modified crops requiring less water -no irrigation

aral sea(ecological disaster resulting from irrigation)

world's largest irrigation canal, 800 miles, diverted water from 2 rivers Kazakhstan and Uzbekistan since 1960, provides water for: cotton, vegetables, fruit and rice

result of sea ecology from aral sea

salinity 3x, 20/24 native fish are extinct, 1/2 bird and mammal populations disappeared