Please have a look at this link and PDF attachments.

https://www.researchgate.net/post/How_to_determine_Cation_Exchange_Capacity

Have a look at this researchgate link also.

https://www.researchgate.net/post/Hi_for_all_I_have_question_in_the_determination_of_soil_exchangeable_Calcium_and_Magnesium_extracted_by_Ammonium_acetate/1

You may use Bower et al. (1952) method , which we find in our laboratory is good. In this method, soil is treated with 1N sodium acetate ( pH 8.2)  to saturate the exchange sites with Na ions. Soluble  sodium is then removed by washing with 95% ethanol. Thereafter, exchangeable Na is extracted with 1N ammonium acetate (pH 7.0). The Na extracted by ammonium acetate is determined by flame photometer.

Arsha , this is the best procedure of determining CEC of  the soil , so conventionally followed  , as narrated by Dr Tarafdar. 

You can use also atomic mass spectrometry, or Testing the Soil with a Test Kit.

In CEC case,  because of the negative charges in their chemical structure, most clay minerals and soil organic matter have the ability to attract or retain positively charged ions (cations) of calcium (Ca++), magnesium (Mg++), potassium (K+), aluminum (Al+++), hydrogen (H+), and others. Attraction between the clay minerals and these ions is weak enough that an exchange between ions can occur; those ions most strongly attracted or occurring at higher concentrations in the soil solution may displace other ions from exchange "sites" on the clays.

The capacity of a soil to retain cations under specific conditions is called the "cation exchange capacity" (CEC). This property affects the availability of potassium, calcium, and magnesium to plants. The term used to report CEC is milliequivalents/100 grams (me/100g) of soil.

A recent addition to the Kentucky soil test results reports a "calculated CEC" that uses results from the current extractant in the Kentucky Soil Test Lab (Mehlich III). This extractant is different from most standardized research procedures used to measure CEC. The information on the soil test report is strictly an "estimate" of potentially exchangeable ions based on the amount of potassium, calcium, and magnesium extracted by the Mehlich III extractant, and an "estimate" of hydrogen from the buffer pH reading. Therefore, the CEC reported as part of the soil test results is usually higher and should not be directly compared to results conducted by the research method.

Fortunately, most agricultural soils are rather uniform in their CEC due to the vast majority having a silt loam texture. The few high-clay soils occurring in certain areas have much higher CEC's, and the rare sandy loams have much lower CEC's. Because these variations are localized, county Extension agents can use their personal knowledge of the local soils to make any adjustment in fertilizer rates for those occasional soils with unusually low or high CEC's.

May be traced back to the parent material and soil type to the soil sample.

 Thank you so much, Dr.Arvind Singh, Dr.Tarafdar, Dr.Anoop Kumar Srivastava, Dr.Iuliana Florentina Gheorghe and Dr.Nurdin, it was very helpful.

Hi Arsha

I think that the best method for CEC determination is a 0.1 M BaCl2 extraction (Hendershot and Duquette 1986).

For this method, you need around 1 gr of dry soil sample weight in a 50 ml centrifuege tubes. Then, you add 30 ml of 0.1 BaCl2 and you shake during 2 hours. Centrifuge (10 minutes at 3000-5000 rpm) and finally you filtered your extraction.

Measure the extracts by ICP or AAS, and you can obtain your data. Finally, you need to conver these data to cmol(+)/kg soil.

It's a very fast, robust and it'swidely reccomended for a wide range of soils.

Exchangeable cations (Ca2+, K+, Mg2+, Na+, and Al3+) were extracted with 0.1 M BaCl2 (Hendershot and Duquette 1986). The single BaCl2 extraction method recommended by the Expert Panel on Soil (2003) also uses the "sum of cations" approach to obtain the effective cation exchange capacity (ECEC), and includes H+ in the calculation, which is determined from the same extract by base titration (Schwertfeger and Hendershot 2009).

Hendershot WH, Duquette M (1986) A simple barium chloride method for determining cation exchange capacity and exchangeable cations. Soil Sci Soc Am J 50:605–608. doi:10.2136/sssaj1986.03615995005000030013x

Expert Panel on Soil (2003) Manual on methods and criteria for harmonized sampling, assessment monitoring and analysis of the effects of air pollution on forests. Part IIIa, Sampling and analysis of soil. Int. co-operative programme on assessment and monitoring of air pollution effects on forests. Institute for Forestry and Game Management, Belgium

Schwertfeger DM, Hendershot WH (2009) Determination of effective cation exchange capacity and exchange acidity by a one-step BaCl2 method. Soil Sci Soc Am J 73(3):737–743. doi:10.2136/sssaj2008.0009

 Thank you so much, Dr.Andrés Rodríguez-Seijo for your valuable reply. 

The only circumstances I know of that are associated with such a low CEC are sand with little to no clay or organic material 

 Arena,as mentioned by Dr.Milham , your estimated CEC values are low . You may check the method and also calculation.If the soils are acidic you can use 0.1 M BaCl2 method.If they are in neutral to alkaline range you can use ammonium acetate or sodium acetate method.In calcareous soils , ammonium acetate  method may give higher values of exchangeable Ca.So effective CEC method of CEC calculation may not work.Methods details are already given by colleagues.You may have to use flame photometer for estimating Na  and K.For Ca and Mg estimation you can use EDTA method ,if you have difficulty in getting AAS.

The ion exchange capacity is denoted by T(cation exchange capacity) + D(anion exchange capacity) , and represents the total sum of cations + anions which can be adsorbed and desorbed by a soil; Is expressed in me / 100 g soil, varies according to pH oscillations.

Cation exchange capacity

- is marked with "T";

- represents the total amount of cations that can be adsorbed and

Desorbed by a soil (Lupascu et al., 1998);

- expressed in me / 100 g of soil,

- varies depending on pH oscillations.

The sum of the exchangeable bases is denoted as "S" or "SB", this is the sum of Ca, Mg, K and Na cations retained in exchangeable forms by the adsorbent complex of the soil and expressed in me / 100 g of soil.

Degree of saturation in bases

- is marked with "V";

- express the extent to which the soil is saturated with exchangeable bases

(Reversible retained bases);

- is expressed as a percentage;

- is determined using the formula: V=S/T*100

Iuliana

On the south coast sandplain soils in Western Australia I have measured Cation Exchange Capacities of less than 0.5 meq/100g using an ammonium chloride solution. The ratio of sand:silt:clay in these soils is 97:1:2%  and the organic carbon content is about 0.3%. Hence very high sand and very low organic carbon contents can give soil CECs 

Very interesting David..I dont think , her soils are as  sandy ...

Thank you, Dr David John Michael Hall for your valuable comment. 

My soil is sandy in nature and organic carbon content is varies from 0.22 to 1.22%.

In the procedure ID: 2720(Part-XXIV), 1967,  amount of

calcium present is estimated by titrating against standard Versene

solution by the addition of 10 ml pH 10.0 buffer and 10 drops EBT

indicator and 1 ml of NaCN.

Is there any error when we carry out the titration without NaCN? 

Arsha, looking at organic carbon  content , such extremely  low CEC seems unlikely..despite soils  are sandy in nature , however the  information on sand percentage would further reveal better interpretation....

Addition of Erichrome Black T as an indicator to estimate Ca plus Mg ( maintaining pH at around 10 is very critical) and ammonium purpureate for estimation Ca act quite effectively..  KCN is more frequently sued than NaCN...

Thank you, Dr.Paul Milham for your reply. You are correct because my soil is sandy in nature. Soil texture follows the order sand>clay>silt. Thank you so much.

Sir, 

The sand percentage is above 70%. clay percentage varies from 3 to 25% and silt is 4 to 15%.  

Arsha Krishnan kindly guide me if reading is 41 soil wt 1 g and extract volume was 24 what CEC will be