Quantity-Intensity Relationship of Potassium in Foothill Acid Inceptisols of West Bengal

Quantity-intensity relationship of potassium in thirteen foothill acid Inceptisols of West Bengal with varying physico-chemical characteristics and forms of available and reserve K were assessed. The equilibrium activity ratio of K(AR^0K_e) varied from 2.7 × 10⁻³ to 17.2 × 10⁻³ (mol/l)^0.5, indicating higher availability of K to growing crops. However, potential buffering capacities of K ranged from 3.64 to 15.96 [cmol/kg/(mol/l)^0.5], indicating a poor potential for long-term K supply. The quantum of labile K adsorbed at specific (Kx) and non-specific sites (Ka) of soils was 0.034 – 0.088 and 0.018 – 0.244 cmol/kg respectively. Free energy for K-(Ca + Mg) exchange varied from −3514 to −2414 cal/mol, indicating sufficiency level of standing crops. Equilibrium activity ratio had significant positive correlation with exchangeable K, non-specific and specific site-K and significant negative correlation with clay content. Labile K showed significant positive correlation with exchangeable K, non-specific and specific site-K and potential buffering capacity of K.