Soil

1
Soil
Much more than "dirt"
2
Why is soil important?
Soil is the growing medium for our food Without
it we could not survive Soil purifies our
waste Soil is home to plants and animals It may
take up to 100 years to form one inch of
topsoil We are losing so much soil to erosion
each year that the lost soil if loaded into dump
trucks parked back to back would extend to the
moon and back. An earthworm can work a ton of
soil a year
3

• Soil is made up of mineral grains.
• Water is held between the grains in the pore
  spaces.
• 25 of the soil is air. Oxygen is essential
• Organic matter is both coarse and fine.
• Bacteria- A thimble of soil can contain 2 billion
  bacteria, 30 million fungi fragments and 100,000
  single cell plants and animals.

What makes up soil?
4
Animals making burrows in the soil help bring air
and water into the soil
5
Inner and Outer Coastal Plain

• Generally, Inner Coastal Plain soils are
  fertile(they can support hearty natural growth of
  a wide variety of plants)
• The upper layers of the Inner Coastal Plain soils
  are brownish and remain moist between rains
• Outer Coastal Plain soils are very sandy,
  infertile, and chemically acidic.
• OCP soils capture water well, but it quickly
  percolates into the lower layers.
• OCP soils have a light color
• Blueberries and cranberries are well suited to
  growing in infertile soil of the OCP.

6
Humus gives the topsoil a rich brown color
Leaching takes minerals carried by water to the
subsoil
Topsoil
Subsoil
Weathered Bedrock
D
Bedrock
7
In a mature soil profile, there are three
distinct layers(horizons) of the soil. The
undisturbed rock below the soil is called the
bedrock. The Ao-horizon consists of the highly
decayed organic material referred to as the peat
and humus. Humus gives soil horizon A a rich
brown color.We see no such brown layer in the
Pine Barrens.
8
In the A horizon, water percolates downward and
carries minerals as it goes. This is called
leaching. Leaching carries minerals down into
the lower soil horizons.
9
The B-Horizon is called the subsoil. This horizon
is where the leached minerals from horizon A end
up. These leached minerals may color the subsoil.
For example, the presence of iron my color the
subsoil red.
Horizon B-Zone of Accumulation of leached minerals
10
The C-horizon is called the zone of weathered
bedrock. When you have a residual soil, one
formed over the original bedrock, the C-horizon
resembles the bedrock, but it is weathered. In a
residual soil, the bedrock is below the
C-horizon. Remember that the Coastal Plain does
not have bedrock under the soil profile, but it
has layers of sand, clay and gravel. That is
because of the sea level changes over time and
the rivers that flowed over it.
11
Soil texture refers to grain size
Sandy particles are the only particles which may
be large enough to be seen with the naked eye.
Predominantly sandy soil has a gritty feel
(coarse-textured) when rubbed between the
fingers. Silt particles are smaller than sand
particles. Predominantly silty soils feel powdery
(like flour) and do not hold together well when
wet, though they are more cohesive than sandy
soils. Clayey soil has the smallest soil
particles, and many small pore spaces. Soils with
a high number of clay particles have a very high
water holding capacity and are very
fine-textured, making them feel smooth and sticky
(like soap) when wet.
Loam is the best soil texture for growing things.
It is a mixture that has useful amounts of clay
and silt in a base of sand.
12
Soil Fractions
13
Soil texture graph
14
Soil Fractions
The top sieve is gravel- set aside The second and
third sieves are sand The fourth sieve is
silt The bottom pan is clay
15
Coarse-textured soils have a high sand content.
They consist of large particles with uneven
surfaces and because of this, have large pore
spaces These traits make such soils loose and
easy to work however, the large spaces do not
retain water or nutrients. Water infiltrates
sandy soil and percolates (moves through it)
quickly and easily. As a result, sandy soils are
generally dry and infertile. The dryness of
sandy soil contributes to a shortage of nutrients
because of less vegetative growth and, therefore,
less organic matter is produced.
16
Medium-textured soils known as loams, have
properties in between those of coarse and fine
texture. Silty loams to sandy-clay loams have a
good capacity to retain water without becoming
waterlogged. They are easy to work and form good
clumping mixtures during cultivation. Loams
contain a good supply of nutrients, necessary for
the organisms living in the soil. Loam or silty
soils have a texture which is most suitable for
the greatest variety of living organisms.
17
Fine-textured soils range from silty clay to
heavy clay. Heavy clays are like soft plastic
when wet and are hard when dry. This makes them
difficult to work. Clays are often waterlogged
and poorly aerated, as well as being cool. Clay
soils absorb and release water (to plants) very
slowly. Air movement within the soil is also very
slow. These conditions mean that clay soils take
longer to warm than coarser soils. A lot of
water in the spaces can mean little air is
available for living organisms to carry out
cellular respiration and certain biochemical
actions.
18
Fertile soil contains nutrients. There are major
nutrients and micro nutrients. Major nutrients
make up the bulk of the nutrients in your soil.
The most important major nutrients are Nitrogen,
Potassium and Phosphorus. Other major nutrients
are Calcium, Magnesium and Sulfur. Micronutrients
are Manganese, Iron, Copper, Zinc, and Boron.
Nutrients need to be balanced and available to
the plant's roots. Organic matter is key to
helping maintain this balance.  
Fertile soil contains nutrients
19
Ion exchange in soil
20
Application of lime helps to neutralize acidic
soil. The calcium and magnesium ions in lime
will bump some of the hydrogen ions off the clay
particles. The hydrogen is then leached downward
by water and the soil becomes less acidic.
21
Acid Loving Plants
22
(No Transcript)
23
(No Transcript)
24
Soil Testing Kits