REN R314 Lecture Notes - Lecture 21: Soil Fertility, Lignin, Soil Ph

• School: University of Alberta
• Department: Renewable Resources
• Course: REN R314
• Professor: Scott Chang

Document Summary

Lime requirement is determined by: change required in ph or exchangeable al saturation, buffer capacity of the soil, chemical composition of the liming material, fineness of the liming material example: Loam soil, initial ph 5 (50% base saturation), cec 10cmol/kg. To raise ph to 6. 8 (90% bs) in the 0-15cm: how much dolomitic limestone with caco3 equivalent of 90. Mg/m3: limestone is not pure (contains mg), but for calculation purposes just caco3. The key is to bring the bs to the level needed- to replace acidic cations with base cations ca, in this case. 10 cmol/kg x (90/100-50/100) = 4cmol ca/kg soil. 4 cmol/kg x (40g/2 ca/mol) x (1 mol/100 cmol) = 0. 8g ca/kg soil. 0. 8g ca/kg soil x (100 (caco3)/40 (ca)) = 2g caco3/kg soil. Purity conversion 3. 9 x 100/90 = 4. 3 ton caco3/ha. 2g caco3/kg x (10 000m2/ha x 1. 3 mg/m3 / 1000kg/mg) x 0. 15m = 3. 9 ton: 2g/kg same as 2kg/mg.