Bulk Density calculations Oven dry weight/ volume ( you need to know this) What is the bulk density of the following: 1. A soil sample with a volume of 100 cc weighs 150g. 2. A soil sample with a volume of 120cc weighs 155g. 3. A soil sample with a volume of 90 cc weighs 100g 4. You take a soil sample with a metal can. The diameter of the can is 8cm. and the height is 5 cm . What is the volume of the sample? If the dry weight of the sample is 250g what is the bulk density? 5. You take a soil sample with a container that is 6cm wide and 4cm high. The weight of your sample is 190 g. What is the bulk density? Is this root inhibiting? 6. The volume of soil taken is 200 ml and the weight is 370 g. What is the bulk density? CEC What is the ppm of the following ions? Calcium (Ca+2) atm weight 40.08 Magnesium (Mg+2) atm weight 24.31 Sodium (Na+1) atm weight 22.99 Potassium (K+1) atm weight 39.10 Formula % ion divided by 100 x TEC Answer x 10 x atm weight divided by valence (charge) 1. TEC = 22, Ca is 76% 2. TEC = 25, Mg is 12% 3. TEC = 26.3, Na is 5% 4. TEC = 20, K = 8% Answers: 1. 150 = 1.5 g/cm3 100 2. 155 = 1.29 g/cm3 120 3. 90 = .90 g/cm3 100 4a.pi r2 x height 3.14 x 42 x 5 = 3.14 x 16 x 5 = 251.20 b.250 = .995 g/cm3 251.2 5. pi r2 x height 3.14 x 32 x 4 = 3.14 x 9 x 4 = 113.04 190/113.04 = 1.68 yes 6. 370/ 200 = 1.85 g/cm3 ppm 1. 76/100 x 22 = .76 x 22 = 16.72 16.72 x 10 x 40.08/2 = 16.72 x 10 x 20.04 = 3350.69 ppm calcium 2. 12/100 x 25 = .12 x 25 = 3 3 x 10 x 24.31/2 = 30 x 12.16 = 364.80 ppm magnesium 3. 5/100 x 26.3 = .05 x 26.3 = 1.32 1.32 x 10 x 22.99/1 = 13.2 x 22.99 = 73.57 ppm sodium 4. 8/100 x 20 = .08 x 20 = 1.6 1.6 x 10 x 39.10/1 = 16.0 x 39.1 = 625.60 ppm potassium