L1 /
8
CH3041
MEASUREMENT OF CEC
1) 3 x 1.0M NH4Cl
• analyse metals
gives Ca2+, Mg2+..
gives Ca2+, Mg2+..
• 2)
1.0M NaCl
• analyse NH4+
gives the total CEC
The CEC is the cmol/kg
of NH4+ ie. millimol / 100g
gives the total CEC
The CEC is the cmol/kg
of NH4+ ie. millimol / 100g
• Smectite 120 cmol / kg
• Other soil
materials with
large CEC’s are:
large CEC’s are:
Allophane CEC 60
(in 3-5nm spheres)
(in 3-5nm spheres)
Organic matter CEC 350
(carboxyl groups)
(carboxyl groups)
