I don't even have a figure one in my lab manual so your guess is as good as mine.
1. Procedure a. Place in three test tubes respectively, I ml of (a) distilled water, (b) the water extract of the soil from part B.l.d. above; and (c) the KCI extract of the soil from part B.1.d. above. b. Test each solution for Ca by adding 5 drops of saturated ammonium oxalate. Shake and allow to stand for 3 minutes. A white cloudy precipitate of calcium oxalate indicates the presence of Ca 2. Results for calcium test. a. Why is more Ca" present in the KCI extract than in the water extract? b. Why is some Ca removed when leached with pure water? Suppose a very dilute solution of KCI were used. the calcium? cations. Would it have removed See text about relative strength of adsorption of the various c. d. Write a cation exchange equation which shows what occurred in respect to all of the cations involved when the soil under study was leached with KCL. Represent the clay particle as it is in Figure 1. V. CATION EXCHANGE CAPACITY A. Principles Soils differ in the quantity of adsorbed cations they contain per unit weight. The cmol, of adsorbed cations per Kg of soil (cmol/Kg) are the units used to describe cation exchange capacity. The higher the clay and humuÅ content of a soil, the greater the cation exchange capacity. Verify the relationship between eation exchange capacity and clay content as follows:
