LaMotte 1067 User Manual

Soil

Texture
Studies

CODE 1604

TEACHER UNIT

CODE 5688

QUANTITY CONTENTS CODE

1 *Texture Dispersing Reagent, 60 mL *5644WT-

H

2 Soil Separation Tubes, 10-40 mL,

w/plastic caps
1 Plastic Ruler 0170
2 Soil Sample Bags 0615
2 Soil Texture Studies Instruction

Manuals

TEACHER UNIT REFILL PACKAGE

CODE R-5688

1 *Texture Dispersing Reagent, 60 mL *5644WT-

0763

1604

H

STUDENT UNIT

CODE 5689

5 *Texture Dispersing Reagent, 60 mL *5644WT-

H

15 Soil Separation Tubes, 10-40 mL,

w/plastic caps
15 Plastic Rulers 0170
30 Soil Sample Bags 0615
15 Soil Texture Studies Instruction

Manuals

0763

1604

STUDENT UNIT REFILL PACKAGE

R-5689

5 *Texture Dispersing Reagent, 60 mL *5644WT-

H

*WARNING: Reagents marked with a * are considered hazardous substances.
Material Safety Data Sheets (MSDS) are supplied for these reagents. For your
safety read label and accompanying MSDS before using.

To order individual reagents or test kit components, use the specified code
number.

2

WHAT IS SOIL?

Figure 1.
Adding Dispersing Reagent

40 mL

10 mL

Soil is an important natural substance. Not only does it make up the
natural covering of the earth, it also supports most plant life. Think
what the world would be like without soil or the plants that grow in
soil. There would be no trees, flowers, fruits or vegetables.

Soil is formed over a long period of time from natural forces acting on
rocks and vegetation, a process called weathering. Weathering results in
different size particles that create the texture of soil. You can tell
whether soil is mostly sand, silt or clay by touch. An abundance of sand
gives the soil a gritty feel when rolled between the fingers. Soil with a
high silt content feels silky to the touch like talcum powder. Moist clay
makes soil feel sticky. The soil scientist can distinguish these various
types of particles according to their size; clay particles are the smallest,
silt particles are medium sized and sand particles are the largest. Soil
particles can also be determined by their different settling rates in a
solution.

Soil is composed of a mixture of mineral matter, organic matter and
humus. These materials help to improve the texture and saturation level
of the soil so air, water and nutrients are more easily available for the
plants. Plants absorb nutrients from these materials through small root
hairs and then use the nutrients to create new plant tissue and for
reproduction.

PLANTS AND SOIL

Plants require nutrients to survive and grow. Nitrogen, phosphorous and
potassium are critical to the plants, as are smaller amounts of sulfur,
iron, manganese, calcium, boron, copper and zinc.

It is not only critical that the nutrients are in the soil, but that they are
available to the plants. The availability of nutrients is highly dependent
on the pH of the soil; if the pH is not in the proper range the plants
will not be able to pull the necessary nutrients from the soil. Proper pH
ranges vary from plant to plant.

If soil lacks one or more nutrients, the plants develop mineral
deficiencies, which are signified by spots on the leaves, dead areas along
the leaf margin or stunting of the plant.

Man-made chemicals that are used to control weeds, insects and disease
should be handled with care. Their effect on other living things should
be carefully studied to make sure that they don’t interfere with the
natural process.

3

SAMPLING TIPS

Figure 3.

Measuring the

height of soil

fractions

40 mL

10 mL

Figure 2.

Shaking the tube

4

0

m

L

1

0

m

L

1. When sampling a lawn, take sample from the upper 2 or 3 inches of

soil. When sampling a garden or farm crops, take sample from the
upper 6 or 8 inches of soil.

2. When sampling a lawn or other specific area, take samples from

several different areas and mix them together. The resulting samples
will provide an average value representative of the entire area.

3. A clean trowel, spoon or knife should be used to collect the samples.

4. Do not touch the soil unless necessary.

COLLECTING SAMPLES

1. Clean area of leaves and plants.

2. Use trowel or other tool to collect 4 or 5 heaping teaspoons of soil.

3. Spread soil thinly on piece of clean paper or plastic to dry. Leave for

several hours or overnight.

NOTE: Do not bake soil to dry.

4. Remove leaves, stones, roots and other foreign matter.

5. Crush lumps until they are less than g“ in diameter.

6. Place soil samples into soil sample bags (0615).

PROCEDURE

1. Fill Soil Separation Tube (0763) to 10 mL

line with soil sample. Gently tap the tube
after each portion is added to pack the soil
down and eliminate air spaces. Place the
plastic ruler (0170) next to the tube.
Measure the total height of the soil. This is
Reading A.

2. Add tap water until the tube is filled to the

40 mL line.

3. Hold the bottle vertically and add 10 drops

of *Texture Dispersing Reagent (5644).
(Figure 1)

4

4. Cap and shake for 2 minutes. (Figure 2)

5. Allow the tube to stand undisturbed for

30 seconds.

6. Place plastic ruler next to tube. (Figure 3)

Measure the height of the particles that have
settled. This is the sand portion of the soil.
This is Reading B.

Percent Sand =

7. Allow tube to stand undisturbed for 30

minutes.

8. Use the ruler to measure the total height of

the particles that have settled. This is
Reading C.

9. Subtract the sand height (Reading B) from

total height of the soil that has settled
(Reading C). This represents the silt portion
of the soil.

Percent Silt =

10. Subtract the Percent Sand and the Percent

Silt from 100%. This is the Percent Clay.

Percent Clay = 100% - Percent Sand - Percent Silt

For example:

Initial amount of soil: Reading A = 1.35 cm
After 30 seconds: Reading B = 0.80 cm
After 30 minutes: Reading C = 1.30 cm

Percent Sand =

Reading B x 100

Reading A

(Reading C - Reading B) x 100

Reading A

0.80 cm x 100

1.35 cm

= 59%

Percent Silt =

Percent Clay = 100% - 59% - 37% = 4%

(1.30 cm - 0.80 cm) x 100

1.35 cm

5

= 37%

GLOSSARY OF TERMS

ABSORB - To take a substance into the physical structure of a liquid or
solid without chemical reaction.

AVAILABILITY - Nutrients in solution which are capable of being
used by the plant.

BACTERIA - Microscopic single-celled organisms which are helpful in
increasing soil fertility. They break down complex substances, fertilizer,
and vegetable matter in the soil by decay and convert these substances
to simpler forms which can be used by plants.

CLAY - The smallest particle size in soil; has the tendency to become
sticky or greasy to the touch when wet. When clay becomes dry it is
extremely hard and brick-like.

FUNGUS - A primitive group of plants characterized chiefly by the
absence of chlorophyll; includes mushrooms, molds, mildews, rusts and
smuts which live primarily on dead or living organic matter.

HUMUS - The well decomposed vegetable and animal material in the
soil which is capable of holding large amounts of plant nutrients and
moisture.

LEAF MARGIN - The border or edge on a leaf. A leaf margin may
take many shapes or forms such as smooth, saw-like, or tooth-like.

MINERAL DEFICIENCY DISEASE - A disease in plants which is
caused by the lack of one or more of the important plant nutrients.

MINERAL SOIL - A general term used for a soil composed chiefly of
inorganic matter, in contrast to an organic soil which is composed
chiefly of organic matter.

ORGANIC MATTER - The fraction of soils which result from the
decomposition of plant and animal matter through the action of
micro-organisms. Organic matter in soils can be increased by the
addition of manure, compost, and peat moss. Soils which are rich in
organic matter have a high water holding capacity and are usually well
aerated. (See humus)

pH - A measurement based on the number of hydrogen ions in a
substance. A pH scale is used to determine whether a substance is acid,
basic, or neutral. On a pH scale the midpoint is 7.0 indicating a neutral
substance; readings below 7.0 are acidic; readings above 7.0 are basic.

ROOT HAIRS - Very small roots of a plant which take in nutrients
from the soil solution.

SAND - Small rock fragments that make up the mineral portion of the
soil. Sands represent the largest particle size in textural classification
and are formed through erosion of native rock material.

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SETTLING RATE - The amount of time required for particles in a
solution to settle.

SILT - A type of soil that falls in size between sand and clay. It is
usually found in combination with one or the other of these soil
fractions.

SOLUTION - One or more substances dissolved in a liquid.
STUNTING - One of the plant symptoms observed as the lack of

growth and development of plant parts.
TEXTURE - The relative amounts of sand, silt, and clay in a soil

determine the structural components or texture of the soil.
TEXTURE DISPERSING REAGENT - A solution composed of

special chemicals which help the soil particles to become easily
separated.

WEATHERING - Worn, disintegrated, or changed by the action of the
elements; wind, rain, sleet, snow, freezing, thawing can all be responsible
for breaking up rocks to form smaller particles.

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LaMOTTE COMPANY

Helping People Solve Analytical Challenges

PO Box 329 • Chestertown • Maryland • 21620 • USA

800-344-3100 • 410-778-3100 (Outside U.S.A.) • Fax [phone]

Visit us on the web at www.lamotte.com

SM

1604 • 11/01