Soil Composition & Properties (College Board AP® Environmental Science): Flashcards
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Define soil water holding capacity.
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Cards in this collection (18)
Define soil water holding capacity.
Soil water holding capacity is the total amount of water that soil can retain and make available to plants.
Why do sandy soils have low water retention?
Sandy soils have low water retention because of their large particle size and high drainage.
From largest to smallest, the three soil particle types are sand, , and clay.
From largest to smallest, the three soil particle types are sand, silt, and clay.
Why do clay soils drain poorly?
Clay soils drain poorly because their small particles give low permeability and high water retention.
Define soil texture triangle.
A soil texture triangle is a diagram used to classify soil types based on their proportions of sand, silt, and clay.
soils have balanced water retention and drainage, making them ideal for agriculture.
Loamy soils have balanced water retention and drainage, making them ideal for agriculture.
How does organic matter affect a soil's water holding capacity?
Organic matter increases water holding capacity by improving soil structure, so humus-rich soils retain more water and nutrients.
True or False?
Clay soils hold nutrients poorly.
False.
Clay soils drain slowly but hold nutrients well.
How does soil compaction affect water holding capacity?
Compaction reduces pore space, which decreases water infiltration and retention, as seen on overgrazed land.
Where are silt-rich soils often found?
Silt-rich soils are often found in floodplains and river valleys, where they are highly fertile.
What does soil pH testing determine?
Soil pH testing determines soil acidity or alkalinity, which can affect nutrient availability.
Soil nutrient analysis measures levels of nitrogen, phosphorus, and .
Soil nutrient analysis measures levels of nitrogen, phosphorus, and potassium.
What does a bulk density test assess?
A bulk density test assesses soil compaction and porosity.
True or False?
A permeability test measures the salt concentration of a soil.
False.
A permeability test measures how quickly water drains through soil; salt concentration is found by salinity testing.
How does a soil texture test separate the soil particles?
Soil is shaken with water in a transparent container and left undisturbed so it settles into distinct layers, whose thicknesses show the proportions of sand, silt, and clay.
What do biological soil tests measure?
Biological soil tests measure microbial activity (the presence of beneficial microbes) and organic matter content.
How is a soil's class found on a soil texture triangle?
Follow the lines for the sand, silt, and clay percentages until they intersect; the intersection point gives the soil classification.
Why is soil testing useful for land managers?
Soil testing provides information for irrigation, fertilizer application, and land management.
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