what is a soil test

7/27/2019 What is a Soil Test

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OBJECTIVES

1. Determine what is a soil analysis.

2. Identify and describe the various tests required for the analysis of soils

and the metología to use .

3. Determine how soil analysis helps in different branches of engineering.



What is a Soil Test?

A soil test is a process by which elements (phosphorus, potassium, calcium,

magnesium, sodium, sulfur, manganese, copper and zinc) are chemicallyremoved from the soil and measured for their "plant available" content

within the sample. The quantity of available nutrients in the sample

determines the amount of fertilizer that is recommended. A soil test also

measures soil pH, humic matter and exchangeable acidity. These analyses

indicate whether lime is needed and, if so, how much to apply.

Why Do You Need A Soil Test?

Encourage plant growth by providing the best lime and fertilizer

recommendations.

When growers guess about the need for lime or fertilizers, too little or too

much is likely to be applied. By using a soil test report, the grower does not

need to guess.

Diagnoses whether there is too little or too much of a nutrient.

Promotes environmental quality.

When gardeners apply only as much fertilizer as is necessary, nutrient runoff

into surface or ground water is minimized and natural resources are

conserved.



Taking a Good Sample

A soil sample must be taken at the right time and in the right way. The toolsused, the area sampled, the depth and the correct mix of the sample, the

information provided, and packaging all influence quality of the sample.

Time it right.

Take a soil sample a few months before starting any new landscaping-whether your laying sod, starting a vegetable garden, putting in a flower bed,

or planting perennials. If the soil test report recommends lime, you will have

enough time to apply it and have it adjust the soil pH before you plant.

Sample established areas-lawns, trees, shrubbery, and other perennials-once

every three or four years. You can sample at any time of year; however, mid-

August through mid-September is an ideal time to take samples for cool-

season grasses, such as fescue, bluegrass, and ryegrass. By sampling at thistime, you can be ready to apply lime in the fall.

For areas recently limed or fertilized, delay sampling at least six to eight

weeks.



Use clean sampling equipment.

Use a soil probe, spade, hand garden trowel, or shovel to collect samples. Do

not use brass, bronze, or galvanized tools because they will contaminatesamples with copper and/or zinc.

Mix samples in a clean, plastic bucket. If the bucket has been used to hold

fertilizer or other chemicals, wash it thoroughly before using it for soil

samples.

Sample each unique area separately.

Each sample should represent only one soil type or area-for example, a lawn,

vegetable garden or perennial landscaped area (Figure 1). For each unique

area, take at least six to eight subsamples and combine them to make one

sample. If one area of your yard seems healthy and another has bare or

yellow areas, sample healthy and unhealthy areas separately even if both are

lawn grasses or flower gardens, etc.



Soil Tests

The Squeeze Test

One of the most basic characteristics of soil is its composition. In general,

soils are classified as clay soils, sandy soils, or loamy soils. Clay is nutrient

rich, but slow draining. Sand is quick draining, but has trouble retaining

nutrients and moisture. Loam is generally considered to be ideal soil because

it retains moisture and nutrients but doesn’t stay soggy.

To determine your soil type, take a handful of moist (but not wet) soil from

your garden, and give it a firm squeeze. Then, open your hand. One of three

things will happen:

It will hold its shape, and when you give it a light poke, it crumbles.

Lucky you—this means you have luxurious loam!

It will hold its shape, and, when poked, sits stubbornly in your hand.

This means you have clay soil. It will fall apart as soon as you open your hand. This means you have

sandy soil.

Now that you know what type of soil you have, you can work on improving it.



The Percolation Test

It is also important to determine whether you have drainage problems or

not. Some plants, such as certain culinary herbs, will eventually die if theirroots stay too wet. To test your soil’s drainage:

Dig a hole about six inches wide and one foot deep.

Fill the hole with water and let it drain completely.

Fill it with water again.

Keep track of how long it takes for the water to drain.

If the water takes more than four hours to drain, you have poor drainage.

The Worm Test

Worms are great indicators of the overall health of your soil, especially in

terms of biological activity. If you have earthworms, chances are that you

also have all of the beneficial microbes and bacteria that make for healthy

soil and strong plants. To do the worm test:

Be sure the soil has warmed to at least 55 degrees, and that it is at

least somewhat moist, but not soaking wet.

Dig a hole one foot across and one foot deep. Place the soil on a tarp

or piece of cardboard.

Sift through the soil with your hands as you place it back into the hole,

counting the earthworms as you go.

If you find at least ten worms, your soil is in pretty good shape. Less than that

indicates that there may not be enough organic matter in your soil to support

a healthy worm population, or that your soil is too acidic or alkaline.



Ph Test

The Ph (acidity level) of your soil has a large part to do with how well your

plants grow. Ph is tested on a scale of zero to fourteen, with zero being veryacidic and fourteen being very alkaline. Most plants grow best in soil with a

fairly neutral Ph, between six and seven. When the Ph level is lower than five

or higher than eight, plants just won’t grow as well as they should.

Every home and garden center carries Ph test kits. These kits are fairly

accurate, but you must make sure you follow the testing instructions

precisely. Once you know whether your soil Ph is a problem or not, you can

begin working to correct the problem.

If you find that you’ve done all of these tests, and amended the soil as

needed to correct the issues, and your plants are still struggling along, the

next step is to contact your local cooperative extension service. They will tell

you how to go about collecting a soil sample and sending it into their lab for

analysis. They will return a report that will alert you to any mineral

deficiencies in your soil, as well as steps to correct the issues.

These tests are simple, inexpensive ways to ensure that your garden has the

best foundation possible.

CBR

CBRstands for Californian Bearing Ratio which is used to determine the

compressive strength of a soil usually for the purpose of determining the"Box Depth" of a road pavement. CBRs can be tested wet (soaked) or dry,

although wet is the industry standard as it allows a road to be designed to

better cope with stresses placed on the subgrade after it has been subject to

significant amounts of moisture.



Soaked CBRs must remain under water for 4 days before being measured for

shrinkage or swell and then tested as to there bearing capacity in that state.

(The test usually takes 7 to 10 days in total).

EMERSON CLASS

Soil cohesion is vital for structures such as road embankments and the like.

Civil Engineers often need to know if a soil will hold together satisfactorily on

its own or whether it may need to be supported or even replaced. One group

of soil tests used to determine cohesion properties of soils is called the

Emerson Class.



GRADINGS

Particle Size Distribution test results (or Gradings) are used for many reasons

such as determining the compliance of manufactured gravels with required

standards and specifications in the earthwork and concrete stages of

construction works.

This Soil test is also part of the process used to classify a soil sample in

conjunction with Atterburg Limits testing.

FIELD DENSITIES

In soil testing for civil construction, Field Density testing would be amongst

the most common. Its purpose is to determine the Field Dry Density (in t/m3)

and Moisture Content (as a %) of the material being tested.



The Field Dry Density is usually compared with a laboratory compaction test

of the same soil type, to produce a ratio between field and laboratory

compaction.



Conclusions

1. A soil analysis is a methodology used to see nutrient deficiencies,

density and plasticity of it.

2. The evidence in a soil analysis is small town of Squeeze, percolation,

worm and Ph.

3. Soil analyzes can be used in different branches of engineering such as

civil engineering helps determine the soil moisture and density that is

vital in the construction and chemical engineering to formulate specific

fertilizer for that soil type.



BIBLIOGRAPHY

1. LOPEZ RITAS , J. and MELIDA LOPEZ , J. 1990. Diagnosis of soils and

plants . Field and laboratory methods . Ed University Press 363 p

4th Ed

2. LOTTI , G. and Galoppini , C. 1986. Agricultural Chemical Analysis . Ed

Alhambra. 440 p .

3. MARAÑÉS , A; SANCHEZ JA, DE HARO , S. , Sánchez , ST and LOZANO ,

F.J 1994. Soil Analysis . Department of Soil Science and

Agricultural Chemistry . University of Almería . Almería . 130 pp .

4. VILLALBI , I. and VIDAL, M. 1988. Soil and leaf analysis : interpretation

and fertilization. Monographs of the agricultural work of the

Foundation Pension Fund. 201 p . Barcelona

5. (Anónimo) disponible en: es.Wikipedia.org/wiki/soil test. date of

consultation: 10/12/2013

what is a soil test

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