Soil Texture in 14 minutes

Summary

In this educational video, Sir Roger, the Dean, delves into the concept of soil texture, a fundamental and unchanging soil property. He explains that soil texture is determined by the relative proportions of sand, silt, and clay, which together form the soil's matrix. The lecture covers various methods for soil texture classification, including the USDA and ISSS systems, and discusses the technical aspects of determining soil texture through field and mechanical analysis. Sir Roger also touches on the significance of particle size, the hydrometer method, and the international pipette method. The video is designed to aid students in understanding soil texture for competitive exams, with a call to action for viewers to engage with the content by subscribing and asking questions.

Takeaways

• 🌱 Soil texture refers to the relative proportion of sand, silt, and clay in the soil.
• 🔍 Soil texture is a basic and permanent property of soil, which does not change with management practices.
• 📏 The size of soil particles (sand, silt, and clay) is crucial for determining soil texture.
• 🏆 The USDA classification and the International Society of Soil Science (ISSS) classification are major methods for classifying soil texture.
• 📊 The USDA classifies soil into seven categories, while ISSS uses four categories, highlighting the distribution of soil separates.
• 🧪 Soil texture can be determined by field methods and mechanical analysis, including hydrometer and pipette methods.
• 🌡 The hydrometer method, developed by Boyd in 1927, is a relatively rapid technique compared to the pipette method.
• 🔬 The pipette method, introduced by GW Robinson in 1922 and modified by HM Anderson in 1928, is considered more accurate for soil texture analysis.
• ⚖️ Specific surface area is the ratio of the total surface area of soil particles to their mass or volume, with clay particles having a much higher specific area than sand.
• 📈 The soil textural triangle is a useful tool for visually determining soil texture classes based on the proportions of sand, silt, and clay.

Q & A

What is soil texture?

Soil texture refers to the relative proportion or percentage of three soil separates: sand, silt, and clay.

Why is soil texture considered a basic and permanent property of soil?

Soil texture is considered a basic and permanent property because it does not change with soil management practices and is a fundamental characteristic that influences other physical properties.

What are the three soil separates and their roles in soil structure?

Sand and silt form the skeleton of the soil, providing structure and support, while clay is referred to as the flesh of the soil, influencing water retention and nutrient availability.

What are the major classifications of soil texture?

Major classifications include the USDA classification, the International Society of Soil Science (ISSS) classification, and the Pipette method classification.

How many categories does the USDA classification have for soil texture?

The USDA classification has seven categories for soil texture.

What are the two methods used to determine soil texture?

Soil texture can be determined by field methods and mechanical analysis, which includes particle size analysis.

What is the hydrometer method and who developed it?

The hydrometer method is a relatively rapid method for soil texture determination developed by Boyd in 1927.

What is the international pipette method and who modified it?

The international pipette method is a preferred method for soil texture determination, originally given by GW Robinson in 1922 and later modified by HM Anderson in 1928.

What is the significance of the specific surface area of soil particles?

Specific surface area is the ratio of the total surface area of the material to its mass or volume, indicating the amount of surface area available for interaction with water and nutrients.

What are the assumptions and limitations of the hydrometer method?

The hydrometer method assumes that soil particles are spherical, rigid, and smooth, and that there is no Brownian movement. Limitations include the requirement for uniform particle density, constant temperature, and still suspension during analysis.

How can one determine the soil texture class using the USDA soil textural triangle?

By observing the proportions of sand, silt, and clay, one can plot these on the USDA soil textural triangle to determine the soil's textural class at the point of intersection of the plotted lines.

Outlines

00:00

🌱 Introduction to Soil Texture

This paragraph introduces the topic of soil texture, emphasizing its importance as a fundamental and permanent property of soil. Sir Roger, Dean explains that soil texture refers to the relative proportion of sand, silt, and clay in the soil. These components form the matrix of the soil, with sand and silt constituting the 'skeleton' and clay being the 'flesh'. The paragraph also discusses the criteria for classifying soil as sand, silt, or clay based on their respective percentages. Additionally, it touches on the major classifications of soil texture, including the USDA classification and the International Society of Soil Science classification, highlighting the seven categories recognized by the USDA and the four by the I Triple S.

05:00

🔬 Methods for Determining Soil Texture

The second paragraph delves into the methods for determining soil texture, which include field methods and mechanical analysis. The mechanical analysis is further divided into the hydrometer method and the international pipette method. The hydrometer method, introduced by Boyd in 1927, is a relatively rapid technique that involves using a Calgon solution to disperse soil particles before measuring them. On the other hand, the international pipette method, introduced by GW Robinson in 1922 and later modified by HM Anderson in 1928, is considered more accurate. The paragraph also mentions the need for removing organic matter and rocky constituents before analysis, and it briefly introduces Stokes law, which is relevant to the mechanical analysis of soil particles.

10:01

📊 Soil Texture Analysis and Specific Surface Area

The final paragraph discusses the assumptions and limitations of the textural analysis method, such as the requirement for soil particles to be spherical, rigid, and smooth, and the need for a uniform temperature and still suspension during analysis. It also introduces the concept of specific surface area, which is the ratio of the total surface area of the material to its mass or volume. The paragraph provides examples of specific surface area for different soil types and mentions the highest specific surface area found in vermiculite. It concludes with a brief explanation of how to determine soil texture using the soil textural pyramid or triangle, where the proportions of sand, silt, and clay are plotted to identify the soil's textural class.

Keywords

💡Soil Texture

Soil texture refers to the relative proportion of different soil particles, specifically sand, silt, and clay. It is a fundamental property of soil that influences its physical properties and management practices. In the video, the lecturer emphasizes that soil texture is a permanent characteristic and is crucial for understanding soil behavior. The script mentions that soil texture can be determined by the relative proportions of sand, silt, and clay, and it is a key factor in soil classification.

💡Sand

Sand is one of the three primary soil separates, characterized by its larger particle size compared to silt and clay. In the context of the video, sand forms the 'skeleton' of the soil, providing structure and drainage. The script specifies that a soil is considered sandy if it contains more than 70% sand and less than 15% clay.

💡Silt

Silt is a soil separate with particle sizes finer than sand but coarser than clay. It contributes to the soil's capacity to hold water and nutrients. The video script indicates that silt, along with sand, forms the soil's 'skeleton,' and a soil is classified as silty if it contains at least 80% silt and less than 12% clay.

💡Clay

Clay is the finest of the soil separates, known for its ability to retain water and nutrients due to its small particle size. In the video, clay is referred to as the 'flesh' of the soil, implying its role in binding soil particles together. A soil is classified as clayey if it contains at least 40% clay.

💡USDA Classification

The United States Department of Agriculture (USDA) classification is a system used to categorize soils based on their texture. The video script mentions that there are seven categories in the USDA system, which helps in identifying soil types and their characteristics. This classification is important for agricultural planning and soil management.

💡Hydrated Soil

Hydrated soil refers to soil that has absorbed water, which is essential for the soil's physical and chemical processes. The video discusses the importance of water in soil texture analysis, particularly in methods like the hydrometer method, where soil particles are dispersed in water to determine their size and distribution.

💡Hydrometer Method

The hydrometer method is a technique used to determine soil texture by measuring the rate at which soil particles settle in a liquid. The video script describes this method as relatively rapid compared to others, and it involves the use of a Calgon solution to disperse soil particles. This method is crucial for understanding soil particle size distribution.

💡International Pipette Method

The international pipette method is another technique for soil texture analysis, mentioned in the video as a more accurate but slower method compared to the hydrometer method. It involves the use of a pipette to measure the settling of soil particles in a graduated cylinder, providing a detailed analysis of soil texture.

💡Specific Surface Area

Specific surface area is the ratio of the total surface area of soil particles to their mass or volume. The video script explains that clay particles have a much higher specific surface area than larger soil particles, which influences their water retention and nutrient exchange capabilities. This concept is important for understanding soil's physical properties and its interaction with water and nutrients.

💡Soil Textural Triangle

The soil textural triangle is a graphical tool used to classify soil texture based on the proportions of sand, silt, and clay. The video script describes how this triangle is used to plot the characteristics of a soil sample and determine its textural class. This tool is essential for soil scientists and agronomists to quickly identify and classify soil types.

Highlights

Soil texture refers to the relative proportion of sand, silt, and clay.

Soil texture is a basic and permanent property of soil.

Sand and silt form the soil's skeleton, while clay is considered its flesh.

Soil texture is determined by the percentage of sand, silt, and clay present.

USDA classification categorizes soil into seven textural classes.

International Society of Soil Science (ISSS) classifies soil into four textural classes.

Soil particles are categorized based on their diameter.

Clay is defined as soil containing at least 40% clay particles.

Silt must contain at least 80% silt particles and less than 12% clay.

Sand is defined as soil with more than 70% sand and less than 15% clay.

Soil texture can be determined by field methods or mechanical analysis.

Hydrometer method and international pipette method are used for mechanical analysis.

Hydrometer method is a rapid technique developed by Boyd in 1927.

International pipette method is a preferred technique for clay soils, modified by HM Anderson in 1928.

Soil texture analysis involves removing organic matter and rocky constituents.

Stokes law is fundamental to understanding soil particle sedimentation.

Assumptions of the pipette method include spherical, rigid, and smooth particles.

Specific surface area is the ratio of total surface area to mass or volume.

Clay particles have a significantly higher specific surface area compared to other soil particles.

The USDA soil textural triangle is a tool for identifying soil textural classes.

Transcripts

hello dear students this is Sir Roger

Dean again with the second video and the

first lecture video the Pala video app

Sabini daily hoagie just like a man hope

Corral and in the first video we have

discussed about avi you know check your

competitive status to obser be up no

competitive status I actually John shook

a hangi kaypea hey so let us start with

the lecture video so today's topic is

soil texture so starting with the soil

texture definition we are very much

aware that soil texture refers to the

relative proportion or percentage of

three soil separates and which are sand

silt and clay so job ehim sand silt and

click a relative proportion Quora

forgotten that is designated as soil

texture the second Joe point at ahead

that soil texture is the basic and

permanent property of soil a basic you

kagayaki basic or permanent property of

soil here those horizon hey hey KJ Joe

property has oil key which comes under

physical properties Jacob he V

management practices Skiba JC Jana you

get all 10 aug 2013 14 million cubby

aapke soil texture change who sat there

otherwise yeh soil texture cubby changed

nahi hota as such

next Johan textual determination Curtin

to juvy soil particles are k - mm sasada

hangi diameter may they will not be

considered in the soil textural

determination minded dear then now out

of three soil separates your sand and

silt they form the skeleton of the soil

your clay is referred as the flesh of

the soil and all three of them all

together form the matrix of the soil now

AB Kia prerequisites Hank is disco harm

you no money or hunka hunka clay hunk of

clay cassock there so clay will only be

called as clay

when it must contain at least 40% of the

clay then silt must contain at least 80%

of the silk and 12 all less than 12% of

the clay and in case of sand if it

contains more than 70% of the sand but

with that it should you know contain

less than 15% of the clay so it now cook

clear Hojo Koga let us move on to the

next topic now let us talk about the

major classifications of the soil

texture there are a number of

classifications but comes if major

classifications by the ending icky most

of the question sub k in Edo

classification say pooja garden the

first classification is USDA

classification that means United States

Department of Agriculture or do rajo

classification and that was given by I

Triple S that means International

Society of soil science or easy

classification go home at a Burks

classification genome say be in John

Thain those subset Bella question aapke

is Samantha a key according to USDA

kidney categories soil separates could

agree so as you can see that according

to USDA there are seven categories but I

Triple S key agura but can item

oppressive four categories highlight

hood the distribution has a Jobin

Tehelka then quotient bantha up cocky

according to USDA Kiptyn e

categories miss and Cody white Kyogre so

according to SDA as you can see there

are five categories which have been

given to the sin but in case of I Triple

S only two categories have been

designated to the sin then or Kalakaua

question is urban sector kick click a

size kitna hota hai so you can easily

see that it is less than point zero zero

two mmm so in synthetic a say of course

sorry K sorry Jo diameter say yup Co

Yadkin a RP hopper apne video pause

querque in cone note down correct there

and then memorize them then acre barking

apples you Artyom mostly you see

that this silt

diameter in case of USDA ranges from

0.0 0.0 5mm by

you see cojo sighs hey i triple-s May

that ranges from point zero zero to two

point zero 2 mm to a half per point zero

five her USD MA or aapke Issa I triple s

my point zero two mmm then

yato bath hui Hammadi teen soil separate

ski but but in say oh but a

separate so then they have been

categorized to a guru round shape ke hum

yes uh Brown shaped Yong a so other

point to say 0.5 centimeter and key

diameter at Oh fine gravel smudging he

see tariqa say 0.5 say point 2

centimeter while a medium gravel me are

saying it and as I move on caretaker

they objects acting core Belkis I say

7.62 25 centimeter here is stone cop car

25 to 60 centimeter hair or bald Erica

it is more than 60 centimeter lake in a

guru up cacio soil separate her both

flat hair soju channa here

so channel Casa Hogar point to say Lake

a 15 centimeter then flagstone Kara I

engage open Drusilla K 38 centimeter

thick range carbon or stone 38 silicate

head up a 60 centimeter or boulders same

ragas sak acapella valley man more than

60 centimeter now let us talk about the

determination of soil texture so this

soil texture can be determined by two

methods one is field method and the

another one is mechanical analysis so

basically two question Arthur have a

mechanical analysis parts Arthur disco

hum particle size analysis can arm say

be John thing so under this category as

you can see that there are two methods

one is hydrometer method and the another

one is international pipette method the

direct question BIA sakta hai ki console

method out of these soil texture

determination Gilly use over to Aqua do

Newnham pathani sahih a Kogi aapke

hydrometer method and another one is

international pipette method a binky

Panama coach highlight some pilot gives

you hydrometer method that was given by

Boyd quest in the 19th in the year of

1927

then agar is a compare can a relatively

rapid method as compared to

international people method but it's my

kia cadenza from dispersion

carvanha hooter hammock Oh soil

particles car those colleges Felician

user there that is named as Calgon

solution originally question puja

bachata through Calgon solution Akiho

takea hey this is the five or ten

percent of sodium hexametaphosphate so

is comb Calgon solution cane am so

hunting or jovem hydrometer ki baat

karta nato is co calibrate k jata at 20

degree celsius

yeah fa 68 degrees celsius agar aapke

temperature about 20 degree celsius a

sixty degree Fahrenheit pending here

so then aku correction factor in our use

kinda bodega moving on again i'm

international piped method key bath

korean so that was given by GW robinson

in the year of 1922 like in so are some

present time international preferred

method for low curtain that was modified

by a HM Anderson in the year of 1928

so agar rapid method puja to hydrometer

of cancer hoga lake in most accurate

method pooja gotta high then

international payment method will be

your answer then couch cushions or

bantha hamper ki aapke Pataki soils my

different the rocky constituents pies

okay to aghanim textual analysis curtain

sep11 come a remove quite now with that

so again my organic matter go remove

kinda here then what is the way to deal

the hydrogen peroxide up you squaring a

six to thirty percent aqui range of U

square sector hang up then a good-sized

Q oxides have key so up sodium sulphide

and oxalic acid mixture you squaring it

and in case of carbonate or exchangeable

mid metal square the domination so Abu

say dilute hydrochloric acid say create

crying here then moving on you bought

the Rudy up a claw head that is the

Stokes law to sell a question how much

Abuja gotta aching mechanical analysis

ka khalsa lawful follow Jota here though

your answer is a Stokes low so the soil

texture analysis Kelly because low here

so this is Stokes law so Stokes loca

kehta hai ki jo aapke velocity have

falling particle ski would directly

proportional UT he was K square of

radius K so particle Caray D s of K

square K directly proportional Hootie

here not to its surface and moreover it

is inversely proportional to

viscosity of the liquid in which it is

traveling so up the exact thing the

pores cooking Harper no down curse

attack or of course if it na drachma v

is directly proportional to R square and

inversely proportional to Nita that

meter denotes the viscosity of water and

rest of the description is there in the

video so you can pause the video note

down this but safe it nanny Agatha the

beak abruptly assumptions Bipasha

limitations say be questions been there

so let us talk about some limitations

and office talk slow then first

assumption is that your particles must

be spherical rigid and smooth though up

to two particles have a spherical be

unity rigid beneath your smooth mmunity

the visa Caracas to explore so apply

hoga then Brownian movement in a human

acharya or generally they kageki Joe

particles is in casa is point zero zero

zero two MMC Nietzsche Jota they exhibit

this you know the Brownian movement or

who ski possesses a rate of falling have

aa very Curt ahead those talks Lama para

apply nano SATA or hoga be thoroughfare

error op geudaega then your particles

must be of uniform density on each

jianchi then your temperature should be

you know like constant throughout the

above is custom machine current and one

more thing that the suspension must be

still up was still rek ennopp cusco hill

on adoulin in a year or a me show you

the he up jump point 0 8 mm Cesare the

Joe but a particle so then they you know

settle very fast though wooden Kiva's is

a turbulence caused ho sakta a medium

may so these are the assumptions and the

limitations of this talk slow moving on

the another one is a specific surface

area it's a be a quotient a sec therapy

exams may so basically german is

specific surface area ki baat karta it

is the ratio of the total surface area

of the material divided by the mass of

it otherwise bulk volume so total

surface area per unit of mass or the

volume so easily juice key unit hand

that can be you know meter square per kg

meter square

per gram if it is like in terms of mass

then in terms of volume it can be meter

square per meter cube or generally per

meter then equation bought you know her

bark which I think a big about that clay

particles you know this clay particles

have 10,000 times more specific area

than the same talk we attract Nike cents

a clay particle catch a specific area

here surface area would thus hajar guna

hota

then here also you can pause the video

up put the kraaho became anecdote tables

there this may have course pacific area

their gags certain minerals car or

certain size fraction scar so RP has a

readout kar saktha and to just you know

dictate some of them you can see that

sand loam soil ranges 10 to 40 meter

square per gram loamy soils car fifty

two hundred meter squares per gram and

clay soil car 150 to 250 meter square

per gram then in case of clearly night

it ranges from 37 to 45 and so on and

vermiculite has got the highest with

specific area out of all the claim

endures that is 780 to 900 now in this

you can see that the there are twelve

textural classes of soils as per the

usda so up sub k they accept their nam

sandy soil low me sand sandy loam loam

cell phloem silt sandy clay loam clay

loam silty clay loam sandy clay silt

clay and clay so these are the textural

classes of the soils you can see then

agar aapko pata like an icky soil

texture aquakey ahead then observe

proportions nickel lynge then with the

help of this soil textual pyramid or

which is also known as soil textural

triangle up characteristic they're

plotting curse at them or chopper up

Cuttino point intersect korea that will

be royal textural classes so apne the

hug is your base a that is representing

sin then agar up apne right side the

king then it will be silt and then clay

so accordingly jitna be percentage outta

here you can draw the lines and where

these lines you know intersect that

point will be considered as the soil

textural plus this is all about soil

texture I hope it will be helpful for

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