Soil Resources Flashcards
study of different kinds of soils and their characteristics
Pedology
loose surface material that covers most land. It consists of rock fragments, mineral grains, organic debris, and presence of moisture
Soil
plays a vital role in soil formation
Weathering
An important product of weathering and a mixture of weathered rock fragments, organic materials, grains of minerals, and moisture
Soil
region of loose unconsolidated rock and dust that sits atop a layer of bedrock
Regolith
a biologically active medium and a key component in plant growth
Soil
slow process which is almost 3 cm per hundred of years
Soil formation
Soil formation is a slow process which is almost __ per __ of years
3cm, hundred
Major Layers of Soil
Topsoil
Subsoil
Bedrock
contains small rock particles and decayed matter called humus
Topsoil
small rock particles and decayed matter
humus
beneath the topsoil and made up mostly of pebbles
Subsoil
formed when solid rock breaks up and poorest material in soil
Bedrock
Layers of the Soil
O Horizon - Surface Litter
A Horizon - Topsoil
E Horizon - Zone on leaching
B Horizon - Subsoil
C Horizon - Parent material
Bedrock
topmost layer where leaves and organic matter decompose and forms the humus
O Horizon
where we plant our seeds because it is rich in minerals and humus. It is soft and porous so that plants can stretch their roots with ease
A Horizon - Topsoil
hard and compact so only the roots of big plants can reach this far down
rich in mineral deposits and clay
B Horizon - Subsoil
layer of weathered parent rock and has no organic matter
C Horizon - Regolith
hardest layer and consists of the unweathered parent rock which supports all layers above it
Bedrock
layer of soil bet. A and B Horizon
Eluviation layer - E Horizon
light-colored layer that contains little organic matter
water percolates downward through this horizon so finer particles are carried or washed away
water also dissolves soluble inorganic soil components and carries them to deeper zones called leaching
E Horizon
the deeper zone where water dissolves soluble inorganic soil components
Leaching
Seven Types of Soil
Sandy
Silty
Clay
Loamy
Peaty
Chalky
Alkaline
most porous soil and has bigger particles
allows water to drain easily
warms very fast during spring
Sandy
soil that is easier to cultivate because of the organic material, nutrients, and moisture
silty
smooth to touch and very fertile
retains water pretty well
can hold more moisture which makes it much easier to work with
Silty
have smallest or fine particles
greater water retaining capacity
rich in mineral content
becomes heavy when wet and difficult to cultivate
Clay
Combination of silt, sand, clay, and little humus
very good for gardening
retains water very easily
Loamy
Loamy soil is a combination of, __, __, __, and little __
silt, sand, clay, humus
dark brown soil
saturated with water and rich in organic material
great and very good for soil growing plants
contains fewer nutrients and prone to waterlogging
found mostly in swamps and muddy places where the climate is wet
Peaty
found over limestone beds and deep chalk deposits
needs more watering and fertilizers because it is prone to dryness
not good for plants because it blocks nutrients
Chalky
has a pH above 7 and relatively a concentration of hydrogen ions
found mostly in western soils
Alkaline
Factors that control soil formation
Parent material
Time
Climate
Plants and Animals
Slope
can be a bedrock or layer of unconsolidated deposits
nature of __ influences soils by its rate of weathering and its chemical make-up affects soil’s fertility (factors)
Parent Material
the longer the soil has been forming, the thicker it becomes and the less it resembles the parent material (factors)
Time
most influential control of soil formation, temperature, and precipitation exerts strongest impact (factors)
Climate
__, __ climate may produce a thick layer of chemically weathered soil in the same amount of time that a __, __, climate produces a thin layer of mechanically weathered debris
hot, wet :: cold, dry
amount of precipitation influences the degree to which various materials are removed (leached) from the soil affecting soil fertility
controls the type of plants and animals present in area (factors)
Climate
its function is to furnish organic matter to the soil
when organic matter decomposes, important nutrients are supplied to plants, as well as animal and microorganisms in the soil (factors)
Plants and Animals
plays an active role in the decay of plants and animal remains and some of them aid in soil fertility by fixing atmospheric nitrogen gas into nitrogen compounds
Microorganisms
earthworms and other burrowing animals act to mix the mineral and organic portions of a soil
burrows and holes also aid in the passage of water and air through the soil (factors)
Plants and Animals
has a significant impact on the amount of erosion and the water content of the soil
Slope of the Land
on __ slopes, soils are often poorly developed
little water can soak in so soil moisture may be insufficient for plant growth
Steep
poorly drained and water-logged soils in __ slopes are usually thick and dark because of organic matter that accumulates because saturated conditions retard the decay of vegetation
low
usually form in temperate areas that receive more than 63 cm of rain each year
Pedalfers
Humus and leached soil (quartz and clay minerals present)
Some iron and aluminum oxidesprecipitated; all soluble materials, such as carbonates, leached away
Pedalfers
this soil type is present in Eastern US, most often in forested areas
Pedalfers
In the B horizon, __ contains large amounts of iron oxides and aluminum-rich clays giving it a brown-red color
Pedalfers
found in the dryer western US in areas that have grasses and brush vegetation
Because chemical weather is slower in dry climates, __ generally contains less clay than pedalfers
Pedocal
contains abundant amounts of calcite/calcium carbonate and are typically a light grey-brown in color
Pedocal
Humus and leached soil
sandstone, shale, and limestone bedrock
Pedocal soil
form in hot, wet, tropical areas. Chemical weathering is intense
go deeper than soils that develop in other areas over the same amount of time
large amounts of water in these climates filters out the calcite and silica in these soils washing them out when it rains
distinctive red color because of iron oxide
contains almost no organic materials (thus, less nutrients
poorest soils for farming
Laterite
Soil Composition percentage
45% minerals
25% air
25% water
5% organic matter
good type of soil for plant growth requirements is __
consists of large amount of organic matter that enhances the soil composition
humus
maximum fertility of the soil has pH range of
6.0 pH - 7.2 pH
