Helping People Help the Land

Natural Resources 

Conservation Service

Farm Service Agency

April 2014

Hand-inHand

for
Page 2

Hand-in-Hand for Soil Health

Where does soil come from?

Soil is the upper layer of earth in which plants grow. Soil is needed to grow food for animals and humans. 

But where does soil come from? How is it made?

Soil formation begins with large rock, minerals and humus. Humus is decayed plants and animals. After 

thousands of years, wind, water and organic material break down the surface rock into smaller pieces or 

particles. These small particles form a thin layer of soil. 

As soil particles lay on top of each other, they begin to form layers. These layers are called horizons. You 

can see the various horizons when you dig a hole.

The O horizon is the top layer. 

It is made up of plants that have 

fallen onto the ground (called litter) 

and keeps the soil very healthy. The 

plant litter breaks down or 

decomposes into nutrients that 

make the soil healthier and form the 

next layer.

The A horizon is the living 

layer. This layer is also called the 

topsoil and is where the roots of 

plants grow best. It is also where 

bacteria and fungi live that make the 

soil able to grow plants and hold 

water. 

The B horizon is a tough layer. 

This layer is also called subsoil; 

plants and animals have a hard time 

getting through the B horizon. This 

layer has a lighter color and is made 

from clay minerals and other 

compounds that seep down from 

above.

The C horizon can be very 

deep. It has less living stuff in it than 

any of the layers above. The C layer 

is made by parent material that is 

created from weathered rock.

The D horizon is the bedrock 

that lies beneath the soil. In some 

places this can be quite near the 

surface and in others it is very, very 

deep. 

Soil horizons Next to each horizon, put the letter that matches 

from the description. 

Color the horizons.
Hand-in-Hand for Soil Health

Page 3

clay

loam

sand silt

silt sand

clay

Soil textures

Silt feels silky 

smooth when wet.

Sand particles are much

larger than clay particles.

Sand feels coarse 

and gritty.

Clay feels 

sticky when 

wet.

Loam is a combination of sand, silt and clay.

The texture of the soil particles is classified 

as sand, silt or clay. Sand feels gritty and 

is the larger of the particles. Silt is 

smaller than sand in size and has a 

smooth feel. Clay is smaller and 

feels sticky. 

Materials Needed

1. 2 earthworms (collect from dark-colored moist soils)

2. One or two dishpans or deep containers

3. Soil to fill the containers

4. Dry plant material.

Make your own earthworm farm

Steps

1. Fill one or two dishpans or deep containers with soil. Do not use peat and do not use soil with 

much sand—it’s rough on the worms’ skin. The soil should be kept moist, but not soggy. 

Moisten the soil slowly if needed. It’s a good idea to punch a drain hole in the dishpan to make 

sure no water stays at the bottom of the pan.

2. Add earthworms. Put the earthworms on the surface of the soil in one pan. The other pan can 

be used to see what happens to the soil without earthworms. Be sure the worms get plenty of 

darkness every day so they can work at the surface. If the container has clear sides, keep it 

covered most of the time to prevent algae growth. The sides can be uncovered briefly each 

day or for a whole day every once in while. Caution: A sick worm can infect and kill the whole 

bunch. Avoid this by removing dead worms quickly (if possible), and by starting with healthy 

worms. They should be plump, quick-moving and show no physical damage.

3. Sprinkle dry plant material on the surface. Use dry leaves, grass clippings or plant material 

from your yard or a nearby field. Make a single thin layer, leaving some soil visible. If you use 

two pans, be sure both have the same type and amount of material.

4. Watch what happens. Once a day, for at least a week, take a look in the pan to see if anything 

changes. Look for burrow openings, worm poop, and the disappearance of plant material. The 

worms will bury the plant material in the soil and also mix the soil. 
Page 4

Hand-in-Hand for Soil Health

Arthropods have no backbone, 

however, they do have jointed legs. 

Soil arthropods include ants, termites, 

spiders, mites, centipedes, millipedes 

and many other critters. You would 

probably call them bugs. They stir up 

the soil so that it gets more air. 

They chew up dead plants into 

tiny pieces so fungi and 

bacteria can rot them. They 

are also a food source for 

larger soil animals.

Arthropods

Nematodes are 

tiny roundworms that 

are common in grassland 

soils. They help provide 

nutrients for plants and also 

help mix up the soil.

Nematodes

Protozoa are tiny animals 

that mainly feed on 

bacteria. When they eat 

bacteria, they release 

nitrogen (a chemical that has 

no color or smell) and other 

nutrients (plant food) to use.

Protozoa

Bacteria are tiny, 

one-celled critters that 

aren’t plants or animals. 

They are so small that you 

need a powerful 

microscope to see them, 

but the soil contains huge 

numbers of them.

Bacteria

Fungi are simple plants that 

don’t have chlorophyll (the 

green stuff) that allows 

other plants to make their 

food from the sun. Fungi have 

many filaments or threadlike fibers 

found on plant structures in the soil 

such as roots.

Fungi

Burrowing animals like prairie dogs, ground squirrels 

and badgers like to dig holes in the soil. 

When the animals dig holes, it helps 

mix the soil and allows rainwater to 

enter the soil. This helps feed the 

plants and also helps prevent flooding.

Burrowing Animals

Color and name the soil 

“workers” in the picture below.

Want to journey into the soil? Let’s explore what’s underground.

Journey into the soil
Page 5

Hand-in-Hand for Soil Health

Start

Finish

Healthy Soil

Compacted Soil

water

air

How does water act in the soil?

Water and soil go together hand-in-hand. Water has a 

downward entry into the soil. This is called infiltration. 

Infiltration is an indicator of the soil’s ability to allow water 

to move into and through the soil. The soil temporarily 

stores water, making it available for roots to drink, plant 

growth and habitat for soil organisms. 

When water is supplied at a rate larger than the soil’s 

infiltration capacity, the extra water moves down across the 

land as runoff. When the soil is left bare or has very 

few plants growing in it, it can be washed away. 

That’s called erosion.

Healthy soil is soil that water can 

seep through or infiltrate. 

Infiltrate the soil below by 

finding your way 

through the maze.

Try to infiltrate the healthy soil. Use one 

color to draw water moving through the 

soil, and use a different color to draw air 

moving through the soil. Then try to 

infiltrate the compacted soil.

Over time, farming can cause a 

compaction layer to form in the soil. This 

is a layer that is packed tightly together 

by the weight of tractors driving over it, 

making it hard for water or plant roots to 

get through. Compaction can form soil 

crust, which are bumps on the soil 

surface. Soil crust is a sign of poor 

infiltration.

Compaction
Page 6

Hand-in-Hand for Soil Health

Keeping soil healthy

We benefit from the soil daily. In fact, farmers and ranchers spend their lives using soil to grow nutritious 

crops for food. There are many ways to keep soil healthy. NRCS encourages four practices to help 

improve soil health—no-till, crop rotation, cover crops and prescribed grazing. All of the practices help 

farmers and ranchers keep their soil healthy.

Crop Rotation. Crop 

rotation is growing different 

crops on the same piece of land 

in a planned sequence. Rotations increase 

organic matter and reduce soil erosion.

No-Till. In order to grow crops, farmers 

usually work the soil. They can do this by 

traditional plowing or using a system for 

planting crops without 

plowing up the soil. This 

method is called no-till. 

When farmers use 

no-till practices 

they plant their 

crops with 

machinery that 

hardly disturbs 

the soil.

Prescribed Grazing. 

Prescribed grazing is 

controlling when and 

how much animals 

graze to accomplish 

grass management goals.

Cover Crops. Cover crops are also used 

to increase soil health. Cover crops 

are legumes or grasses that are 

planted after harvesting another 

crop. Cover crops control 

erosion, hold 

phosphorous and 

other nutrients, 

and improve 

infiltration.

BADGER

CLAY

COMPACTION

EROSION

FUNGUS

HEALTHY

HORIZONS

INFILTRATION

MATTER

NUTRIENTS

ORGANIC

PLANTS

PLOWING

ROOTS

RUNOFF

SAND

SILT

STRUCTURE

TEXTURE

TILL

WATER

Soil Health 

Word Search

Circle all the words you can 

find. Hint: all are related to 

soil health.
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Hand-in-Hand for Soil Health

1

5 6

4

7

8

12 13

15

10 11

16

9 14

2 3

What do you know about soil health?

Soil Health Crossword Puzzle

Across

Down

2. tiny animals that mainly feed on bacteria

5. growing various crops on the same piece of land in a planned sequence

8. layers formed from soil

9. simple plants that don't have chlorophyll

11. forms bumps on the soil surface

15. tiny roundworms that are common in grassland soils

16. has smooth texture

1. infiltrates soil

3. tiny, one-celled critters that aren't plants or animals

4. upper layer of earth in which plants grow

6. plant food

7. have jointed legs, no backbone

10. decayed plants and animals

12. feels gritty

13. feels sticky

14. type of grazing that controls when and how much animals graze to 

accomplish vegetation management goals
Page 8

Hand-in-Hand for Soil Health

04/14 MT USDA is an equal opportunity provider and employer.

Connect the dots to see 

the historical Natural 

Resources Conservation 

Service symbol.

The Natural Resources Conservation Service 

(NRCS) provides private landowners with the most 

up-to-date information on how they can improve their 

soil health. In some cases, NRCS can even provide 

financial assistance to start a soil health program on 

their property. NRCS works to help people help the 

land and through them create productive lands and a 

healthy environment.

So what does NRCS have to do with soil health?

p.5 p. 4

p.8

p.7 p.6

p. 2

Answer

 Keys:

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19

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25 24 26

27

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18

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A O Z O T O R P

T

E

I T A O R

L

O

S

N O

U

T

T U R C

I

E

N

S

A

S D T M E N

D

C

L

A

Y

T

H

U

M

U

L I S

S

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S N O Z I R O H

T

H

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P

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P

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E

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R

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B

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I G N U F

A

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Start

Finish

arthropod

arthropod

fungi

bacteria

arthropod

nematodes

burrowing

animal

protozoa

A

O

B

C

D