Abstract:
Twenty acid soils of West Bengal, India, representing Alfisols, Entisols and
Inceptisols orders, were studied to characterize their acidity in relation to
physicochemical properties. Total potential acidity (TPA), pH-dependent
acidity (PDA), total acidity (TA), hydrolytic acidity (HA) and exchange acidity
(EA) ranged from 2.02–6.90, 1.75–6.05, 1.18–2.75, 0.98–1.90 and 0.06–
0.85 cmol(p+) kg−1, respectively. Relative order for all forms of acidity was:
Entisols>Alfisols>Inceptisols. Average contribution of EA to TPA and TA was
9.7% and 19.7%, respectively, and that of PDA to TPA was 90.1%.
Contribution of electrostatically bound H+ to EA was highest for
Inceptisols followed by Entisols>Alfisols, and reverse was true for electrostatically
bound aluminum (Al3+). All forms of acidity showed significant
positive correlations with organic carbon (C) forms of Al but negative
correlations with pH of soil. They also showed significant correlations with
each other. Soil pH, organic C and exchangeable Al caused most of the
variations in different forms of soil acidity.
