Vol. 8, Issue 1 (2020)

Total acidity (TA), exchange acidity (EA), aluminium acidity and pH-dependent acidity (PDA) and total potential acidity (TPA) ranged from 0.1–2.2, 0.1–2.5, 0.1–2.7, 0.0– 4.5 and 0.1– 4.9 cmol(p+) kg⁻¹, respectively. Relative order for all forms of acidity was: Inceptisol >Alfisols >Vertisol. On average contribution of soil acidity due to TPA in Inceptisol, Alfisol and Vertisol was found maximum 35.5%, 35.6% and 32.3% at 0-30 cm soil depth, 36.0%, 34.3% and 33.0% at 30-60 cm soil depth and 35.5%, 34.6% and 33.0% at 60 - 90 cm soil depth, respectively, while, the minimum contribution in soil acidity was due to exchangeable acidity i.e. 9.2, 8.5 and 9.2% at 0-30 cm soil depth, 7.5%, 6.5% and 7.5% at 30-60 cm depth and 5.6, 4.8 and 5.5% at 60 - 90 cm soil depth, respectively. All forms of acidity showed significant positive correlations with organic carbon (OC) 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.