What soil is in your backyard?
Background:
There are 3 main types of soil
Clay- smallest grain size- less than 1/256 of a millimeter- a single grain cannot be seen by itself
without a microscope
Silt- medium grain size- from 1/256 to 1/32 of a millimeter
Sand- largest grain size- from 1/16-1 millimeter- it can be seen with just your eyes
Any pieces larger than sand are pebbles or even boulders
Soils are made of mixtures of different size grains
Experiment:
1. Put 25 grams of soil (about the weight of 10 pennies) in the palm of your hand. Add drops of
water and knead it until soil is moldable like a moist putty.
a. If the soil is too dry add more water
b. If the soil is too wet add more soil
c. If the soil will not remain in a ball when squeezed despite the combination of soil and
water, then it is ……………………………………………………………………………………………...SAND
2. Place the ball of soil between thumb and forefinger. Gently push the soil with thumb, squeezing
it upward into a ribbon of uniform thickness and width. Allow ribbon to emerge and extend over
forefinger, breaking from its own weight
a. If soil does not form any ribbon, then it is…………………………………..…..LOAMY
SAND
b. If it makes a weak ribbon less than 1 inch long before breaking follow steps below. If not
go to C.
i. Add more water and rub between forefingers to find texture
1. If soil feels very gritty………………………………………………SANDY
2.
LOAM
If soil feels very smooth……………………………………………….SILT LOAM
If soil feels neither gritty or smooth…………………….………………….LOAM
3.
c. If it makes a ribbon 1-2 inch long before breaking follow steps below. If not go to D.
i. Add more water and rub with fore fingers to find texture
1. If soil feels very gritty…………………………………SANDY
2.
CLAY LOAM
If soil feels very smooth………………………………….SILTY CLAY LOAM
If soil feels neither gritty or smooth…..…….………………….CLAY LOAM
3.
d. If it makes a strong ribbon over 2 inches long before breaking follow steps below
i. Add more water and rub with forefingers to find texture
1. If soil feels very gritty………………………………………………SANDY
2.
3.
CLAY
If soil feels very smooth……………………………………………….SILTY CLAY
If soil feels neither gritty or smooth…………………….…….…………….CLAY
What does this mean?
Each type of soil has good and bad qualities
Positive
Clay
Fertile
High in nutrients
Holds water for plants
Silt
Sand
Fertile
Holds water for plants
Good drainage
Not easily compacted
Warm up quickly in spring
Negative
Hot in summer and can bake
Cold in winter and can freeze
Drains slowly (can flood plants)
Easily compacted (no spaces for soil animals like worms)
Warm up slowly in spring
Easily compacted (no spaces for soil animals like worms)
Dry (does hold water well for plants)
Acidic
Loams are a good type of soil because they contain parts of all three soil types which means there is less
extreme conditions for each of them.