Lab 4

for question 9, it is asking for the CEC of clay fraction and the soil fraction, isn't it the same??? or do we write the clay fraction as xxx montmorillonite and xxx kaolinite???

AnaisJanik (talk)‎

The question in question is no.10 (not no.9). CEC of clay fraction and CEC of soil are NOT the same. Think about which solid particles can carry negative charge (and consequently contribute to CEC). Hint - soil mentioned in question no.10 contains both organic matter and clay........

And to calculate CEC of clay fraction (as asked in 10a) you do need to take into account percentages of montmoriollinite & kaolinite (as specified in the question) and CEC values for these 2 clay minerals (as specified in table 3 in lab manual for lab #4)

MajaKrzic (talk)‎

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Question9

I double checked, it is question 9 not 10, and organic matter is only added to the soil in 9c, while 9a and 9b does not contain organic matter.

Under those circumstances, is 9a and 9b the same? Given that we dont account for the silt and sand fractions?

Thank you!

AnaisJanik (talk)‎

Yes, you are correct this is question no.9 (I was looking at an older version of the lab manual where this was listed as question no.10)

Question 9a and 9b do NOT ask for the same thing. Pls check how is the question stated (or worded) and what proportion of texture of this soil is comprised of clay

MajaKrzic (talk)‎