Get ahead with a $300 test prep scholarship
| Enter to win by Tuesday 9/24
AP Environmental Science Soil
Terms in this set (87)
relatively thin surface layer of the Earth's crust consisting of mineral and organic matter that is affected by agents such as weather, wind, water, and organisms
What is the composition of soil? (4 Distinct Parts)
What % does mineral particles make up in soil?
What % does organic material make up in soil?
What % does water make up in soil?
What % does air make up in soil?
renewed, growth, purify
Soil is a slowly __________ resource that provides most of the nutrients needed for plant ______ and also helps ______ water.
Soil formation begins when bedrock is broken down by physical, chemical and biological processes called __________.
soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons
horizontal layers of soil
The rock that has slowly broken down into smaller particles by biological, chemical, and physical weathering.
wind, water, and temperature
3 common causes of erosion
sand, silt, and clay
3 textures of soil
If soil has a lot of sand, then it will feel ______.
If soil has a lot of clay, then it will feel ______.
If soil has a lot of silt, then it will feel ______.
How soil particles are organized and clumped together
How easily the soil can be crumbled.
A measure of the volume of soil and the average distances between the spaces.
The rate at which water and air moves from upper to lower soil layers.
4.0 to 8.0
The pH of most soils ranges from _._ to _._.
The soil of the Pygmy Forest in California is extremely ______.
The soil in Death Valley, California, is very _____.
Plants are affected by pH because of the _________ of nutrient minerals.
_____ slopes often have little or no soil on them because of gravity.
____ soil is rich with lots of organic matter.
______ soil (like sand) is not so rich with very little organic matter.
Organic Layer (O-horizon)
The uppermost layer; it is rich in organic material.
Second highest horizon; it is dark and rich in accumulated organic matter and humus.
The Topsoil (A-horizon) has a ________ texture and is somewhat nutrient-____ due to the loss of many nutrient minerals to deeper layers and by leaching.
The light-colored subsoil beneath the A-horizon; it is often a zone of illuviation where nutrient minerals have leached out of the topsoil and litter accumulate.
iron and aluminum
The Subsoil (B-horizon) is typically rich in ____ and ________ compounds and clay.
Parent Material (C-horizon)
This horizon contains weathered pieces of rock and borders the unweathered solid parent material. Most roots do not go down this deep and it is often saturated with groundwater.
the downward movement of water through soil.
dissolving of minerals and organic matter in upper layers carrying them to lower layers.
The ____ ____ determines the degree of infiltration and leaching.
Industrialized agriculture uses about __% of all commercial energy in the U.S.
Out of the 17% of U.S.'s energy usage that industrialized agriculture uses, what percentage is used for crops?
Out of the 17% of U.S.'s energy usage that industrialized agriculture uses, what percentage is used for livestock?
Out of the 17% of U.S.'s energy usage that industrialized agriculture uses, what percentage is used for food processing?
Out of the 17% of U.S.'s energy usage that industrialized agriculture uses, what percentage is used for food distribution and preparation?
planting several genetic varieties.
two or more different crops grown at the same time in a plot.
crops and trees are grown together.
different plants are planted together.
How many tons of soil are eroded in the U.S. every year?
the movement of soil components, especially surface litter and topsoil, from one place to another.
surface water or wind peel off thin layers of soil.
fast-flowing little rivulets of surface water make small channels.
fast-flowing water join together to cut wider and deeper ditches or gullies.
Soil erosion _________ through activities such as farming, logging, construction, overgrazing, and off-road vehicles.
water hits the soil at a severe angle (based on slope)
when surface water moves down a slope or across a field in a wide flow and peels off fairly uniform sheets of soil.
(like in California) where it is very wet and large amounts of soil slip away in large chunks (mud slides).
concentrated flow across the surface of soil. Leaves rivets (micro channels).
rivulets of fast-flowing water join together and, with each succeeding rain, cut the channels wider and deeper until they become ditches.
one particle hitting another and being blown across the surface of the soil.
mountains/sand dunes; surface creeping slowly across.
2. Natural Climate Change
6. Soil compaction
Causes of Desertification (6)
2. Economic losses
3. Environmental refugees
4. Lower living standards
5. Drought worsening
Consequences of Desertification (5)
can reduce wind erosion. Long rows of trees are planted to partially block the wind. They can also help retain soil moisture, supply some wood for fuel, and provide habitats for birds.
to disturb the soil as little as possible while planting crops.
1. Raises soil carbon content.
2. Increases crop yield.
3. Uses less tractor fuel.
4. Lowers water use.
5. Lowers pesticides.
Benefits of Conservation-tillage farming (5):
sloping your growing crops, etc.
(what you use for contour farming.) Dirt goes up to hold the dirt in place. Broad, nearly level terraces that run across the land contour. Helps to retain water for crops at each level and reduce soil erosion by controlling runoff.
Terracing, contour planting, strip cropping, alley cropping, and windbreaks can ______ soil erosion.
a row crop such as corn alternates in strips with another crop that completely covers the soil, reducing erosion.
cover cropping (alley cropping)
several crops are planted together in strips or alleys between trees and shrubs that can provide shade (which reduces water loss by evaporation) and helps to retain and slowly release soil moisture.
Conventional center-pivot irrigation
Irrigation technique that allows 80% of the water input to reach crops
Irrigation technique that uses valves that send water down irrigation ditches.
Irrigation technique that can raise water efficiency to 90-95% and reduce water use by 37-70%.
Irrigation technique that works by allowing the natural floods to irrigate the crops. Soils in flood zones tend to be nutrient rich and fertile.
Nutrients that are larger in atomic structure.
Nutrients that are smaller in atomic structure.
Selenium, Zinc, Iron
Examples of Micronutrients (3)
Nitrogen, Phosphorus, Potassium
Examples of Macronutrients (3)
animal manure, crop residues, bone meal, and compost
man-made fertilizer from chemical compounds
exact compositions are known; they are soluble & thus immediately available to the plant
Benefits of Inorganic Fertilizers
quickly leach away; this pollutes the water; doesn't help the water holding capacity of the soil like organic fertilizers do.
Costs of Inorganic Fertilizers
growing plants in fertilized water.
It is labor-intensive and expensive.
Costs of Hydroponics
You can control the environment & grow plants where there is no soil; NASA is looking into this.
Benefits of Hydroponics
1. Depletion of underground water supplies.
2. Inefficient irrigation methods.
3. Salt build-up.
4. Cost of irrigating crops.
Since 1978 the amount of irrigated land per person has declined due to (4 reasons):
Taking a species of plant or animal and improving it by making the better characteristics more prominent.
picking and choosing "good" traits from two or more different organisms to combine to make a new organism