Midterm Exam Questions

Low (i.e. acidic) pH is part of the answer. The other part is related to the type of the colloids, since not all soil colloids will change it charge with change in pH of the soil solution. Only organic matter and Fe/Al oxides/hydroxides change their pH with a change in pH of soil solution. Elaboration of how that change occurs is also needed as part of the answer for this question (pls see lecture notes from Feb 12)