The following data were collected in measuring cation-exchange capacity (CEC) for two Illinois soils by the rapid diffusion method described in class. In this method, 0.5 gram of NH4+ saturated soil is diffused with magnesium oxide (MgO) to liberate gaseous NH3, which is collected in boric acid-indicator solution and determined by titration with standard H2SO4. Soil Milliliters of 0.008 M H2SO4 A : 8.78 B : 3.92

1. For each soil, calculate the milligrams of NH4+ liberated by diffusion. 2. Using your values from question 1, calculate the CEC of each soil. Express your answers in meq/100 g.

3. For both soils, the exchange composition is 75% Ca, 12% Mg, and 2% K. Use your CEC values from question 2 to calculate the pounds per acre of these nutrients in the plow layer of each soil, assuming the usual weight of 2 million pounds to a depth of 6 inches.

4. Suppose that you have an opportunity to purchase 100 acres on either soil for crop production, at a price of $8,000 per acre. Considering the difference in CEC, which would be the better buy and why?