ABSTRACT A study was undertaken to optimize the parameters for particle size analysis through laser diffraction techniques. Fifty soil samples with varying soil texture, organic matter, sesquioxide content and calcareousness were collected and analyzed for soil texture by conventional (International Pipette Method-IPm) and Instrumental (Particle Size Analyser-PSA) methods. The study reveals that PSA is more accurate and preferable compared to IPm in determining the soil particle sizes. The clay content of the different samples estimated by International Pipette method and by Particle size analyzer varied from 0.9 to 48.4% and 0.35 to 41.2 %, respectively. PSA showed a good agreement (72% samples) for silt size fractions, and a slight shift in the upper limit of clay from conventional size of 2 µm could help in analysis of soil texture by PSA

Jena

R Jagadeeswaran

R Sivasamy

Roomesh Kumar

CiteSeerX

Original aticle December 2013    Volume 26    Issue 2 78  
Indian Journal of Hill Farming 
Indian Journal of Hill Farming 26(2):78-83                                                                      Available online at www.kiran.nic.in 
 
 
Analogy of Soil Parameters in Particle Size Analysis through 
Laser Diffraction Techniques 
 
 
ROOMESH  KUMAR  JENA1*, R. JAGADEESWARAN2,  R. SIVASAMY2 
 
 
Received November 11, 2013; Revised November 30, 2013; Accepted December 2, 2013 
 
 
ABSTRACT 
 
A study was undertaken to optimize the parameters for particle size analysis through laser diffraction 
techniques. Fifty soil samples with varying soil texture, organic matter, sesquioxide content and 
calcareousness were collected and analyzed for soil texture by conventional (International Pipette 
Method-IPm) and Instrumental (Particle Size Analyser-PSA) methods. The study reveals that PSA is 
more accurate and preferable compared to IPm in determining the soil particle sizes. The clay content 
of the different samples estimated by International Pipette method and by Particle size analyzer varied 
from 0.9 to 48.4% and 0.35 to 41.2 %, respectively. PSA showed a good agreement (72% samples) 
for silt size fractions, and a slight shift in the upper limit of clay from conventional size of 2 µm could 
help in analysis of soil texture by PSA. 
 
Keywords: Soil texture, international pipette method, particle size analyser 
 
 
 
INTRODUCTION 
 
Soil texture is a qualitative classification tool 
used in both field and laboratory to determine 
classes for agricultural soils. The classes are 
distinguished in the field by the ‘textural feel’ which 
can be further clarified by separating the relative 
proportions of sand, silt and clay using grading 
sieves. The class is then used to determine crop 
suitability and to approximate the soil’s responses 
to irrigation and management practices. Traditional 
particle size determination techniques include 
sieves for the larger size ranges, usually above 
63µm (230 mesh size). Sieves are limited in 
resolution (number of sieves = number of data 
channels), they are slow and operator intensive, and 
has limitation for determining the smaller size 
classes. Pipette or sedimentation method is 
generally used for the finer fractions; however, this 
technique is slow and is affected by particle shape. 
Modern automated analytical techniques are 
used for sizing sediments which includes laser 
diffraction and digital image processing. They are 
fast, easy, operator independent, have a much 
broader range and higher resolution with many 
more data channels. In these techniques, particles 
are to be independently suspended in the flow-cell 
and the desirable condition is achieved by agitation 
and ultrasonification whereas the chemical means 
of removing cementation is not followed. Laser 
Diffraction techniques are occasionally applied to 
soil material (Cooper et al. 1984). Laser Diffraction 
Technique measures light scattered from the 
particles suspended in the measurement cell. The 
angle of scatter is related to the size of the particles. 
The measurement is essentially instantaneous, 
although total analysis times are in the order of 30 
seconds for most samples. The instrument is 
popular for this application because of its wide size 
range (0.02-2000 µm), speed, stability and ease of 
use. With this background, the present investigation 
was attempted  to study the  variability  and 
relationship between the international pipette 
method and laser diffraction technique for varying 
soil properties. 
 
1 NBSS&LUP, Regional Centre, Jorhat, Assam 
2 Department of Remote Sensing and GIS, Tamil Nadu Agricultural University, Coimbatore-641003 
* Corresponding author’s Email : roomeshjena@gmail.com 
Indian Journal of Hill Farming 
December 2013    Volume 26    Issue 2 79 
 
 
r 
i 
r 
 
 
MATERIALS AND METHODS 
 
Fifty numbers of surface soil samples were 
collected from different parts of Western Agro- 
climatic Zone of Tamil Nadu representing various 
soil textures and having a wide range of organic 
matter content, sesquioxide content and 
calcareousness. The samples were analyzed for 
texture both by International pipette method (Piper 
1966) as well as by Laser diffraction technique in 
Microtrac S3500 particle size analyzer. The samples 
were also analyzed for organic carbon content 
(Walkley and Black 1934), sesquioxide content 
from HCl extract (Hesse 1973) and free calcium 
carbonate by Rapid titration method (Piper 1966). 
The methodologies followed for particle size 
determination are detailed below. 
 
International Pipette Method 
Twenty grams of soil sample was treated with 
60 ml of 6% hydrogen peroxide and kept over water 
bath for 30 minutes to oxidize the organic matter. 
To this 200ml of N/5 hydrochloric acid was added 
and kept overnight to destroy all the carbonates 
present in the samples. The contents were filtered 
through Whatman No.50 filter paper and washed 
with water till the filtrate ran free of chloride. The 
contents were transferred from filter paper to 
another beaker and 400 ml water was added.  To 
this 8 ml of 1N sodium hydroxide was added to 
deflocculate the finer particles present in the 
samples. The entire sample was stirred through 
mechanical stirrer for 10 minutes to disperse all 
the soil separates. The volume was made up to 1.0 
litre using distilled water in a measuring cylinder 
without spout. The cylinder was tightly closed with 
a rubber stopper and the content was mixed 
thoroughly by repeated inversions holding the 
rubber stopper tightly so as to avoid spilling of the 
soil water suspension. The clay fraction, silt fraction 
and the sand fraction were determined using the 
pipette method as described by Piper (1966). 
 
Laser Diffraction method 
Microtrac S3500 particle size analyzer with a 
780 nm wavelength laser beam was used for 
studying particle size distribution (PSD) of soil 
samples.  Microtrac FLEX software was used for 
calculation of the particle size distribution. The 
analysis was carried out in the laboratory of 
Metrohm India limited, Chennai. The instrument 
measures particle size over the range of 21 nm-2800 
µm in wide angle range of nearly 160 degree. 
Microtrac employs three lasers to emit laser light 
into particles from the best angle. While many other 
particle size analyzers are designed to detect 
particles at a point, the Microtrac detection 
mechanism is designed to detect all the scattered 
light on an entire surface. 
Before analyzing samples in the instrument, the 
sample parameters viz., size and refractive index 
were set up. Since the soil separates are irregular 
in shape, the particle parameters were set 
accordingly. Another important particle parameter 
was Refractive Index (RI), which is a complex 
number comprised of (i) a real part (n ) which 
represents the change in the velocity of light in 
vacuum; and (ii) an imaginary term (n ) which 
represents the transparency and absorptivity of that 
material. The values of the minerals commonly 
found in soil falls between 1.48 and 1.71, but for 
minerals like hematite, the RI may reach values 
from 2.9 to 3.2. Yet, for most minerals an n value 
of approximately 1.52 was suitable. Thus, the RI 
value input was set at 1.52 for the soil samples. 
Two grams of soil sample was taken in a 100ml 
beaker. To this 50 ml of water and 1-2 drops of 
Triton X 100 dispersing agent was added. The 
sample was subjected to ultrasonification and fed 
into particle size analyzer. Before feeding the 
sample to the instrument, samples were drained and 
filled twice followed by the flow of water. Samples 
were analyzed by setting the instrument parameter 
viz., the rate of ultra-sonification at 0.5 cycles with 
40% frequency for 5 minutes. A subset of randomly 
selected samples, ten in number, was subjected to 
different durations of sample cycling in the flow 
cell. The soil textural classes for the above samples 
were identified using soil textural triangle of 
International Society of Soil Science (ISSS scheme 
1929). 
Graphical examination of the data was 
performed using Microsoft Excel spreadsheet 
program. Calculating the percent deviation or 
relative difference between IPm and PSA method 
for clay, silt and sand were done as per the following 
equation: 
 
(a - b) 
Per cent Deviation = ———     X 100 
b 
Indian Journal of Hill Farming 
December 2013    Volume 26    Issue 2 80 
 
 
 
 
Where, 
a = per cent of clay / silt / sand determined 
through International Pipette method. 
b = per cent of clay / silt / sand determined 
through Particle Size Analyzer. 
 
 
 
RESULTS AND DISCUSSION 
 
The clay content of different soil samples 
analyzed by IPm varied from 0.9 to 48.4 per cent. 
The higher percentage of clay (48.4%) was 
observed in two samples (Sample No. 3 and 6) out 
of the 50 samples subjected for particle size 
analysis. The lowest percent of clay was observed 
(0.9%) in the Sample No.16. The silt content of the 
samples varied from 2.5 to 20 per cent and the sand 
content varied from 32.2 to 90.7 per cent. The 
higher percent of silt (20%) was found in Sample 
No. 14 and 24. The lowest silt content (2.5%) was 
observed in the Sample Nos.11, 12, 33, 37, 38, 40 
and 49.  The higher percent of sand (coarse and 
fine fractions) was observed in Sample No.13. The 
lower percent of sand fraction was observed in 
Sample No.3. Eshel et al. (2004) obtained a good 
agreement between measured and calculated laser 
diffraction values for one size class, accompanied 
by poor agreement between measured and 
calculated values for the other class. 
The clay content of different soil samples 
analyzed through Laser diffraction technique (PSA) 
varied from 0.4 to 41.2 per cent. The highest 
percentage of clay (41.2%) was observed in Sample 
No 21. The lowest per cent of clay (0.4%) was 
observed in the Sample No.19. The silt content of 
the soil samples varied from 5.8 to 33.5 per cent 
and the sand content varied from 31.2 to 92.6 per 
cent. The highest percent of silt (33.5%) was found 
in Sample No.3. The lowest per cent of silt (5.8%) 
was observed in the Sample No.10. The higher per 
cent of sand (92.6%) was observed in Sample 
No.10. The lowest per cent of sand (31.2%) was 
observed in the Sample No.3. (Table 1) 
The per se performance of the soil samples on 
pH showed good agreement (50%) between IPm 
and PSA methods of textural analysis. The chi- 
squared test  showed  that  these  groups  are 
significantly different (at 1% level) from each other 
in terms of showing agreement between the two 
methods of textural analysis (Table 2). Soil samples 
based on natural breaks in soil EC value was done 
to check if this soil property has any bearing on the 
choice of the method for textural analysis.  When 
compared to the IPm, PSA produced agreeing 
results (Fig. 1) in terms of soil textural class (38%) 
for soils with low EC (<0.1 dSm-1) in group I 
followed by 0.5-1.0 dSm-1 in group III and 0.1-0.5 
dSm-1  in group II. Loizeau et al. (1994) found that 
laser grain size analysis underestimates the 0-2 
micrometer fraction proportional to the clay content 
as determined by the pipette method. 
On the basis of soil organic matter, about 35 per 
cent samples had good agreement between IPm and 
PSA methods of textural analysis when the organic 
carbon content was below 1 per cent (Fig. 2). When 
the individual soil separates were considered, silt 
content was not comparing well between the two 
methods of analysis (Fig. 3). Grouping of soil 
samples based on calcium carbonate content was 
done to check whether this soil property has any 
bearing on the choice of the method for textural 
analysis. This was in agreement with the findings 
of Zobeck (2004), who obtained a better co-efficient 
of determination between the two methods for non- 
 
 
Fig 1: Effect of soil EC on textural analysis 
 
 
Fig. 2: Percent agreement of soil organic carbon 
content on textural analysis 
Indian Journal of Hill Farming 
December 2013    Volume 26    Issue 2 81 
 
 
 
 
Table 1: Comparison of soil particle sizes estimated by IPm and PSA 
 
 
Sl 
No 
 
International Pipette 
 
% Clay 
 
Method (IPm) 
 
% Silt 
 
 
 
% Sand 
 
LASER Diffr 
 
% Clay 
 
action Technique t 
 
% Silt 
 
hrough PSA 
 
% Sand 
1 18.4 7.5 70.6 10.5 23.5 65.9 
2 23.4 17.5 57.6 25.9 21.9 52.2 
3 48.4 17.5 32.2 35.3 33.5 31.2 
4 5.9 17.5 76.5 6.7 15.9 77.4 
5 35.9 15.0 44.9 25.8 25.5 48.7 
6 48.4 10.0 37.3 37.7 30.1 32.2 
7 23.4 7.5 65.1 10.4 15.6 74.0 
8 20.9 17.5 59.5 11.5 18.2 70.3 
9 20.9 10.0 63.9 9.9 14.3 75.8 
10 3.4 7.5 85.3 1.6 5.8 92.6 
11 25.9 2.5 70.6 11.1 23.3 65.6 
12 5.9 2.5 90.7 2.5 11.0 86.5 
13 5.9 5.0 85.8 1.8 9.8 88.5 
14 18.4 20.0 54.2 2.0 22.8 75.2 
15 23.4 10.0 62.0 10.0 27.1 62.9 
16 0.9 10.0 87.7 6.9 16.6 76.4 
17 10.9 5.0 82.6 6.8 16.6 76.6 
18 20.9 10.0 64.4 11.4 22.8 65.8 
19 5.9 5.0 88.2 0.4 8.3 91.3 
20 10.9 10.0 76.6 6.1 14.5 79.4 
21 35.9 15.0 43.3 41.2 21.7 37.1 
22 20.9 5.0 71.2 11.8 26.2 62.0 
23 20.9 5.0 70.4 15.7 25.3 59.0 
24 25.9 20.0 53.1 10.0 20.3 69.7 
25 43.4 10.0 46.0 9.2 29.0 61.8 
26 45.9 10.0 44.0 23.2 32.5 44.3 
27 10.9 10.0 72.7 8.7 22.3 69.0 
28 20.9 7.5 65.5 13.2 20.8 66.1 
29 15.9 5.0 78.6 6.6 16.3 77.1 
30 3.4 4.0 89.0 2.5 10.1 87.5 
31 28.4 10.0 57.1 20.5 26.6 53.0 
32 8.4 5.0 84.6 3.8 11.0 85.2 
33 10.9 2.5 82.4 6.3 13.3 80.5 
34 15.9 17.5 59.2 11.8 26.6 61.6 
35 5.9 2.5 89.0 6.5 14.8 78.7 
36 10.9 5.0 77.4 5.5 18.3 76.2 
37 20.9 2.5 73.2 9.4 16.3 74.3 
38 15.9 2.5 78.3 9.3 22.1 68.7 
39 10.9 7.5 78.3 7.7 20.3 72.0 
40 18.4 2.5 78.4 7.9 11.6 80.6 
41 15.9 15.0 65.6 21.1 23.5 55.5 
42 10.9 7.5 77.4 5.8 23.7 70.5 
43 23.4 10.0 64.6 14.3 20.2 65.5 
44 5.9 10.0 79.4 4.9 13.1 82.0 
45 20.9 15.0 63.5 8.3 16.7 75.0 
46 8.4 10.0 73.1 10.7 17.2 72.1 
47 13.4 17.5 64.7 13.7 23.5 62.8 
48 18.4 17.5 59.5 5.2 14.0 80.8 
49 13.4 2.5 83.6 2.2 9.7 88.1 
50 15.9 15.0 68.7 5.3 14.7 80.0 
Mean 18.3 9.5 68.9 11.1 19.2 69.7 
S.D. 11.5 5.4 14.4 9.1 6.5 14.3 
C.V. 130.5 28.6 202.3 80.6 41.0 200.1 
Indian Journal of Hill Farming 
December 2013    Volume 26    Issue 2 82 
 
 
 
 
Table 2: Comparative study of soil samples on pH 
basis analyzed by IPm and PSA 
 
pH No. of     No. of samples             Per cent 
based samples   showing agreement      agreement 
Groups  between IPm and PSA 
 
 
I 
 
12 
 
6 
 
50 
II 12 2 17 
III 19 7 37 
IV 7 2 29 
 
 
 
Fig. 3: Agreement between IPm and PSA for Soil 
separate estimation under different groups of soil 
based on Organic Carbon Content 
 
calcareous soils.   Compared to the IPm, PSA 
produced agreeing results (50%) in terms of 
textural class for soils (Fig. 4) with high calcium 
carbonate (15-20%) in group IV, followed by group 
II (5-10%), I (0-5%) and III (10-15%). Grouping 
based on sesquioxide content, about 37 per cent 
samples had good agreement between IPm and PSA 
methods of textural analysis when the sesquioxide 
content was more than 10%. When the individual 
soil separates were considered, silt content was not 
 
 
Fig. 4: Effect of Soil free Calcium Carbonate on 
Textural 
comparing well between the methods of analysis 
(Fig. 5), as also reported by Pieri et al. (2006). 
 
 
 
 
Fig 5: Agreement between IPm and PSA of soil based 
on Sesquioxide Content 
 
 
CONCLUSIONS 
 
Even though it is not explicitly established from 
the present study that what causes the difference 
between the two methods of analysis of soil 
separates, it is found that a relook into the definition 
of size of the soil separates could favour the use of 
laser diffraction-based soil particle size analysis. 
The present findings can be discussed in scientific 
forums and if agreed, the PSA can be recommended 
as one of the important equipment in the soil 
laboratories. 
 
 
 
ACKNOWLEDGEMENT 
 
The authors sincerely thank M/s Metrohm India 
Limited, Chennai for providing technical assistance 
and laboratory facilities to carry out the study. 
 
 
 
REFERENCES 
 
Cooper LR, Haverland RL, Vendricks DM, Knisel WG (1984). 
Microtac particle-size analyzer: An alternative particle- 
size determination method for sediment and soils. Soil 
Sci 138:138–146 
Eshel G, Levyb GJ, Mingelgrinb U, Singera MJ (2004). Critical 
evaluation of the use of laser diffraction for particle- 
size distribution analysis. Soil Sci Soc Am J 68(3): 
736-743 
Hesse PR (1971). A Text Book of Soil Chemical Analysis. 
John Murray Ltd 10–362 
ISSS (International Society of Soil Science) (1929). Minutes 
of the First Commission Meetings. International 
Congress  of  Soil  Science,  Washington  1927. 
Indian Journal of Hill Farming 
December 2013    Volume 26    Issue 2 83 
 
 
 
 
Proceedings of International Society of Soil Science 
4:215–220 
Loizeau JL, Arbouille D, Santiago S, Vernet JP (1994). 
Evaluation of a wide range laser diffraction grain-size 
analyser for use with sediments. Sedimentol 41: 353- 
361 
Pieri L, Bittelli M, Pisa PR (2006). Laser diffraction, 
transmission electron microscopy and image analysis 
to evaluate a bimodal Gaussian model for particle size 
distribution in soils. Geoderma 135: 118-132 
Piper CS (1966) Soil and Plant Analysis. Hans Publisher, 
Bombay 
Walkley AJ, Black CA (1934). An estimation of method for 
determining soil organic matter and proposed 
modification of the chromic acid titration method. Soil 
Sci 27:29–38 
Zobeck TM (2004). Rapid soil particle size analyses using laser 
diffraction. Appl Engin Agric 20(5): 633-639 


Analogy of Soil Parameters in Particle Size Analysis through Laser Diffraction Techniques

http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=D8968244EAD837A28A6A7A43D1DD478F?doi=10.1.1.1071.2579&rep=rep1&type=pdf

Analogy of Soil Parameters in Particle Size Analysis through Laser Diffraction Techniques

Abstract

Similar works

Full text

Available Versions

CiteSeerX