calculation questions

We were told we wouldn't have to do any calculations on the exam, so would calculating the CEC be included or removed? For example, a question like this:

7. A surface soil horizon of an uncultivated site has a loam texture with clay content of 20%. The clay-size fraction is dominated by montmorillonite clay mineral. Organic matter content of this horizon is 6%. 5 (a) Assuming that the CEC of montmorillonite is 100 cmolc/kg and organic matter has CEC of 200 cmolc/kg determine the net negative charge (cmolc/kg) of this soil. (b) The concentrations of exchangeable cations in this surface are: Ca2+ = 23.0 cmolc/kg Mg2+ = 4.4 cmolc/kg K+

= 0.5 cmolc/kg

Na+

= 0.1 cmolc/kg

Calculate the percentage base saturation (BS) of this soil horizon

SophiaChristou (talk)‎

Sophia, You do not require a calculator for the final exam. There are no calculation questions (like the one on the midterm). You should however understand the principal behind the example you give above - that CEC of clay (or organic matter) does not equate to the CEC of the soil. If you have a soil with high clay content (e.g. 40%) what are the implications for CEC (of the soil)? If you have a soil with 15% organic matter, what are the implications for CEC (of the soil)

SandraBrown (talk)‎