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8/9/2019 Globe Protocol

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National Aeronautics and Space AdministrationGoddard Space Flight Center

Flight Projects | Sciences and Exploration

• Biospheric Sciences Research

Guide, Part 2: Horizon Properties

Soil Characterization Step-by-Step Guide, Part 2: Horizon Properties

Soil Structure

Soil structure is the shape that the soil takes ased on its ph!sical and chemical properties" Each indi#idual unit o$

soil structure is called a ped" %ake a sample o$ undistured soil in !our hand &either $rom the pit or $rom the sho#el

or auger'" (ook closel! at the soil in !our hand and examine its structure" Possile choices o$ soil structure are)

Granular: Resembles cookiecrumbs and is usually less than0.5 cm in diameter. Commonly

found in surface horizons whereroots have been growing.

Blocky: Irregular blocks thatare usually 1.5 5.0 cm indiameter.

Prismatic: !ertical columns ofsoil that might be a number of cmlong. "sually found in lower

horizons.

Search SE

http://www.nasa.gov/http://www.nasa.gov/goddard/http://fpd.gsfc.nasa.gov/http://science.gsfc.nasa.gov/600/sci/http://neptune.gsfc.nasa.gov/bsbhttp://www.nasa.gov/goddard/http://fpd.gsfc.nasa.gov/http://science.gsfc.nasa.gov/600/sci/http://neptune.gsfc.nasa.gov/bsbhttp://www.nasa.gov/


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Columnar: !ertical columns ofsoil that have a salt #ca$# at theto$. %ound in soils of aridclimates.

Platy: &hin' flat $lates of soilthat lie horizontally. "suallyfound in com$acted soil.

Single Grained: (oil is brokeninto individual $articles that donot stick together. )lwaysaccom$anies a loose consistence.Commonly found in sandy soils.

Massive: (oil has no visiblestructure' is hard to break a$artand a$$ears in very large clods.

+$ !ou ,ish do,nload the protocol ao#e so that !ou can use it in the $ield- here are pict $iles soil texture page ."

Belo, are some images o$ the di$$erent soil structures"

With Structure:

http://soil.gsfc.nasa.gov/stepbystep2/texture2.pcthttp://soil.gsfc.nasa.gov/stepbystep2/texture2.pcthttp://soil.gsfc.nasa.gov/stepbystep2/texture2.pct


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Structureless:

*ranular

+locky

,rismatic

Columnar

,laty

(ingle *rained

-assive


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Soil Color

/" %ake a ped o$ soil $rom each hori0on and note on the data sheet ,hether it is moist- dr! or ,et" +$ it is dr!-

moisten it slightl! ,ith ,ater $rom !our ,ater ottle"

." Break the ped


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%he 2unsell code elo, each color in the G(3BE color chart is a uni#ersal notation that descries the soils5 color"

Hue

The irst set o nu!ber and letter sy!bols represents the hue" 6ue

represents the position o$ the color on the color ,heel &787ello,-

R8Red- G8Green- B8Blue- 7R87ello, Red- R78Red 7ello,'"

Munsell Notation: #alue


#alue


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The nu!ber beore the slash is the #alue" 9alue indicates the lightness o$ a color" %he scale o$ #alue ranges

$rom : $or pure lack to /: $or pure ,hite"

Munsell Notation, continued: Chro!a


Chro!a

The nu!ber ater the slash is the Chro!a" Chroma descries ho, the ;intensit!; o$ a color" Colors o$ lo,

chroma #alues are sometimes called ,eak- ,hile those o$ high chroma are said to e highl! saturated- strong- or

#i#id" the scale starts at 0ero- $or neutral colors- ut there is no aritrar! end to the scale"

Soil Consistence

Ta$e a ped ro! the top soil horizon" % the soil is &ery dry, !oisten the ace o the proile usin' a (ater

bottle (ith a s)uirt top and then re!o&e a ped to deter!ine consistence"

&Repeat this procedure $or each hori0on in !our pro$ile"'

6olding it et,een !our thum and $ore$inger- gentl! s


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riable

%he ped reaks ,ith a small amount o$ pressure"

ir!

%he ped reaks ,hen !ou appl! a good amount o$ pressure and dents!our $ingers e$ore it

.tre!ely ir!

%he ped can5t e crushed ,ith !our $ingers

Soil Te.ture

%he ,a! a soil ;$eels; is called the soil texture"


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Soil texture depends on the amount o$ each si0e o$ particle in the soil"

Sand- silt- and clay are names that descrie the si0e o$ indi#idual particles in the soil"

Sand are the largest particles and the! $eel ;gritt!";

Silt are medium si0ed- and the! $eel so$t- silk!- or like $lour"

Clay are the smallest si0ed particles- and the! $eel ;stick!; and the! are hard to s


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o +s some,hat stick!

o +s some,hat hard to s


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Soil Te.ture is co!plete"

" Add the ,ord silt or silt! to the initial classi$ication"

Soil texture is &check one')

silt! cla!-

silt! cla! loam-

silt loam



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G" (ea#e the original classi$ication o$ &check one')

cla!-

cla! loam-

loam


+$ !ou ,ish do,nload the protocol ao#e so that !ou can use it in the $ield- here is a jpg $ile) soil texture step 1"

To 1eter!ine Soil Te.ture continued3

Step 4 &%est $or loam! sand or silt' +$ the soil)

• Forms a all

• Forms no rion

• And is

H" 9er! gritt!

Soil texture is)

loam! sand


Or

http://soil.gsfc.nasa.gov/stepbystep2/text4.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text4.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text4.jpg


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%" 9er! so$t and smooth ,ith no gritt! $eeling-

Soil texture is)

silt


Step 5 &%est $or sand' +$ the soil)

Forms no all and $alls apart in !our hand-

Soil texture is)

sand



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+$ !ou ,ish to do,nload the protocol ao#e so that !ou can use it in the $ield- here is a jpg $ile) soil texture steps

="

Presence o 4oots and 4oc$s

Presence o 4oots

3ser#e and record i$ there are none- e(- or !any roots in the hori0on"

Presence o 4oc$s

3ser#e and record i$ there are none- e(- or !anyrocks+ in the hori0on"

+ A rock is de$ined as eing larger than . mm in si0e"

http://soil.gsfc.nasa.gov/stepbystep2/text5.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text5.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text5.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text5.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text5.jpghttp://soil.gsfc.nasa.gov/stepbystep2/text5.jpg


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Test or ree Carbonates

Free caronates are compounds that coat soil particles" %he! $orm under certain conditions such as in dr! climates

,here the p6 is ao#e D" %he! are also $ound in some soil pro$iles that ha#e parent materials made o$ caronates

&such as limestone'"

%his test is per$ormed ! s


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Sli'ht) !ou oser#e a slight amount o$ uling &the soil is coated ,ith some caronates'"

Stron') !ou oser#e a strong reaction &man! ules' &the soil has man! caronate coatings present'"


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