Relationship between Cadmium Fractions Obtained by Sequential Extraction of Soil and the Soil Properties in Contaminated and Uncontaminated Paddy Soils
Table 3
Correlation between proportions of Cd chemical forms and soil propertiesa.
Soil properties
Uncontaminated soils
Contaminated soils
Exchangeable
Inorganically bound
Organically bound
Oxide occluded
Residue
Exchangeable
Inorganically bound
Organically bound
Oxide occluded
Residue
pH(H2O)
(−)
pH(KCl)
(−)
(+)
(−)
(+)
T-C
(−)
(+)
T-N
(−)
(+)
CEC
(−)
(+)
(+)
Ex-Ca
(−)
(+)
(+)
Ex-Mg
(−)
(+)
Ex-K
Base saturation
(−)
(+)
Available phosphate
(−)
(+)
(−)
(+)
PAC
(−)
(+)
(+)
Free iron oxide
Sand
(+)
(−)
(−)
Silt
(+)
(+)
Clay
(+)
Alo + 1/2 Feob
(−)
(+)
(+)
(+): positive correlation, (−): negative correlation, (), (), and (). bExtracted with acid oxalate.