AP Environmental Science Unit 6

what connections (water quality) are there to soil?

soil erosion can increase water turbidity and salinity

where would understanding soil formation be extremely important? think san francisco and colorado river.

we have to look at soil to determine if we can build a dam or building there

if you were building a filtration system, would you only use one type of soil? explain.

no, you would need multiple types of soil because each type helps clean the water

how do pesticides actually affect insects? do they eliminate them? what could pesticides by doing to the nitrogen cycle?

pesticides can cause pesticide resistant organisms to reproduce and the pesticide can kill the bacteria in the nitrogen cycle

what is the biggest problem farms face?

increased salinity, insects eating crops, lack of water, plowing topsoil goes into atmosphere (loss of topsoil)

why did my old backyard have better soil in sacramento than my friend’s backyard in grass valley (up the mountains)?

soil went downhill from the mountain (more fertile soil in sacramento)

what is the most abundant element in the crust?

oxygen

this is a type of boundary where new lithosphere is formed

divergent

this is a type of boundary where volcanoes are formed

convergent

this is a type of boundary where earthquakes occur

transform

why is humus important for soil?

supplies some micronutrients to plants and creates crumbly soil allowing for water absorption and drainage

what can determine the pH of the soil? (FRQ)

temperature, amount of water, amount of organic matter

what is an ideal soil for agriculture?

loam - 40% sand, 40% silt, 20% clay

list the following in order from smallest to largest? gravel, silt, clay, sand

clay, silt, sand, gravel

what is leaching? why is it important?

definition: process of water washing soluble substances, like nutrients or pollutants, through soil and rock
importance: supplies nutrients to roots

would you put a natural septic tank (not plastic tank) over a clay type soil?

no, the water would back flow back up

what type of soil do you think exists where there are signs that say “warning flash flood”?

clay soil

what is a soil profile?

series of horizontal layers of different chemical compositions, physical properties, particle size, and amount of organic matter

what layers do the majority of living organisms reside?

O horizon and A horizon

what limits the leaching in grassland soils?

low rainfall

what factors make erosion worse?

deforestation, overgrazing, salinization, soil compaction, loss of biodiversity

approximately 20% of land in the US is suitable for agriculture (arable). what is happening to this important 20%?

we are putting houses on it

why should we implement important soil conversion practices? (FRQ)

we are losing soil faster than it is being made

describe one soil conservation practice (FRQ - talk about 2 ways)

crop rotation - rotate crops with plants that have nitrogen fixing bacteria

what is chemical weathering?

occurs as a result of chemical interactions between water and other atmospheric gases

define lithosphere

outermost layer of the earth that includes the solid upper mantle and crust

what type of plate boundary causes plates to move apart?

divergent

think about genetic variation from biology. what is wrong with humans relying on 4 species of crops?

crop variation decreases which people can starve if one disappears

what is happening to the nutritional quality of our food when we only rely on feeding crops macronutrients?

the nutritional quality decreases

what role do trees play in the enviornment?

they do windbreaking, hold soil in place, act as a habitat, perform photosynthesis/cellular respiration

seals have been dying along the wadden sea from PCBs. explain how.

PCBs are weakening their immune system

what are three benefits of conventional tillage?

weeds and weed seeds are buried/destroyed, leached nutrients are brought close to surface, cooler and darker soil brought to top and warmed

what was a benefit of the 1st green revolution? a consequence?

benefit: larger crop yield
consequence: pesticides/fertilizers cause runoff

what are the benefits of DDT?

kills mosquitos that carry malaria and kills pests like grasshoppers

what is the name of a pesticide/chemical that lasts a long time in the enviornment?

persistent organic pollutant (POP)

what is another name for pesticides?

biocide

what are two important soil conservation measures/practices? (FRQ)

covercrop and polyculture

what are the chemicals in 24-12-7. state them in order.

nitrogen, phosphorus, potassium

why is a natural A zone with humus broken down better than just receiving synthetic fertilizers? (FRQ)

synthetic fertilizers have no water holding ability like humus and natural A zone has macro/micronutrients (like boron)

why are organophosphates used today instead of hydrocarbons?

organophosphates are short-lived compounds that don’t persist in the enviornment

what pesticide is hurting bees? what is it doing to them?

neonicotinoids - their immune system is weakened

what are some (two) benefits of pesticide use?

larger crop yields, kills pests that harm crops, kills disease-carrying insects like mosquitos that carry malaria

explain the pesticide treadmill

the use of more pesticides due to insects becoming resistant to them and accidentally killing natural predators of pests

what does BT stand for?

bacillus thuringiensis

how do sex pheromones work on insects?

they attract insects to false mates so they don’t produce offspring

is using lady bugs both organic and IPM?

yes

why will you or your wife pass on DDT to your child?

bioaccumulates in your body which passes on to the baby while it is in the womb and through breastfeeding

explain how planting crop cover could benefit a farm after growing corn?

it covers the soil which protects it from water loss and wind loss

crust

extremely thin, less-dense

mantle

makes up majority of the earth (surrounds core of iron)

core

outer portion capable of flow (inner portion is solid due to intense pressure)

plate tectonics

large plates of crust and outer mantle (lithosphere) slowly moving over liquid surface of mantle (asthenosphere)

what causes the plates to move?

heat from earth’s core

convergent boundaries

moving towards each other (produces mountains, volcanoes, and oceanic trenches)

convergent boundaries (continental-continental)

neither plate will subduct because they are the same density (can produce mountains like the Alps and Himalayas)

convergent boundaries (oceanic-oceanic)

recycles crust back into earth, subduction zone (volcanoes and oceanic trenches), volcanic islands form as volcanoes emerge

subduction zone

forms oceanic volcanoes and ocean trenches (Mariana Trench)

convergent boundaries (oceanic-continental)

forms a subduction zone with an ocean trench, forms continental volcanoes (Andes and Cascades)

divergent boundaries

moving away (produces new earth), most exist along oceanic ridges, seafloor spreading occurs along the boundary

how does seafloor spreading occur?

divergent boundaries form fractures on the ridge crusts and the fractures fill with molten material from below (new lithosphere is made!)

transform boundaries

plates slide past one another (produces earthquakes)

what is another way that volcanoes are produced?

hot spots

hot spots

rising plumes of mantle material where volcanoes can form over them

mechanical weathering (physical)

any process that breaks rock down into smaller pieces without changing the chemistry of rock (usally wind and water)

chemical weathering

occurs as a result of chemical interactions between water and other atmospheric gases (also weathering that takes place as a result of living activities like lichen secreting waste to break down rock)

land

portion of world not covered by water

soil

mixture of 45% minerals, 25% air, 25% water, 5% organics (5% living organisms, 10% roots, 85% humus)

parent material

ancient layers of rock or more recent geologic deposits from lava flow or glacial activity

humus

decaying organic material, moves with the top layers of rock, supplies some micronutrients to plant, creates crumbly soil which allows water absorption and drainage (synthetic fertilizers don’t have this)

factors that influence soil formation

earthworms, burrowing animals, plant roots, bacteria and fungi (decomposers), position on slope, climate, time, rainfall, soil pH

porosity

amount of water soil can hold

permeability

rate at which water and air moves through the soil

soil profile

series of horizontal layers of different chemical composition, physical properties, particle size, and amount of organic matter

soil horizon

each recognizable layer of the profile

O horizon

leaf litter, un-decomposed or partially decomposed organic material

A horizon

topsoil, uppermost layer contains most of the soil nutrients and organic matter, dark topsoil is nitrogen rich and high in organic matter, contains humus

what two layers contain the most living organisms?

O and A horizon

B horizon

subsoil, underneath top soil, contains less organic matter and fewer organisms, accumulates nutrients leached from topsoil

where is topsoil poorly developed?

dry areas

C horizon

weathered parent material, very little organic material

what is most cultivated land classified as?

grassland or forest soil

grassland soils

have a deep A horizon, low rainfall limits topsoil leaching, A horizon supports most root growth

forest soils

topsoil layer is relatively thin but topsoil leachate forms a subsoil (B horizon) that supports substantial root growth

what are two factors of great influence in tropical rainforest soils?

high temperatures (rapid decomposition-little litter) and high rainfall (excessive leaching of nutrients, leaching leaves behind iron and aluminum and creates acidic soil)

erosion

wearing away and transportation of soil by wind, water, or ice

soil conversion practices (contour farming)

tiling at right angles to the slope of the land, each ridge acts as a small dam, this reduces water loss and erosion

soil conversion practices (conservation tillage)

reduces the number of times you plow your field (places seeds in silts and use herbicides)

soil conversion practices (windbreaks)

planting trees around farm

soil conversion practices (crop rotation)

rotate crops with plants that have nitrogen fixing bacteria

soil conversion practices (cover crop)

planting nitrogen fixing plants on the field during the offseason

soil conversion practices (polyculture)

planting a variety of crops

soil conversion practices (terracing)

level areas constructed at right angles to the slope to retain water 0 good for very steep land

soil conversion practices (strip farming)

alternating strips of different crops to slow water flow and cover all ground, this reduces use of pesticides and fertilizers as well as soil loss

soil conversion practices (alley cropping - agroforestry)

crops and trees are planted next to each other

green revolution (1952)

monoculture, synthetic fertilizers, and pesticides produced a larger crop yield (greatly increased worldwide food production)

green revolution II (1967)

cross breeding varieties of plants to grow dwarf varieties like rice and wheat that have more seeds

pros of conservation tillage (no till)

reduces erosion, saves fuel, more soil can hold more water, reduces compaction, allows several crops per season, does not reduce crop yields

cons of conservation tillage (no till)

plant residue may delay soil warming, accumulation of plant residue can harbor plant pests and diseases requiring more insecticides and fungicides, requires new expensive equipment

pros of conventional tillage (old school)

weeds and weed seeds are buried and destroyed, leached nutrients brought closer to surface, cooler and darker soil brought to top and warmed

cons of conventional tillage (old school)

when topsoil is lost - soil fertility is reduced or destroyed and fertilizers must be used to restore fertility, loss of soil organic matter, reduced ability to store water for use by crops, increased use of costly fertilizer to maintain soil fertility, increased water runoff, increased sediment runoff into waterways, decrease fish production due to increased sediment (turbidity)