Quantity‐intensity relationships for labile sodium in field soils

Exchange isotherms for Na with Ca+Mg in ten unfertilized soils show smaller buffer capacities for Na than K, larger Na than K activity ratios at equilibrium, and curvatures of the graphs at small Na activity ratios that could indicate larger exchange energies on about 0.5 per cent of the exchange sites.

Since equilibrium Na activity ratios in the soils were similar to those in rain, the latter ratios could be most important in controlling Na activity ratios in soils and the percentage saturation of exchange complex with Na. The geochemical significance of these ratios is discussed. RESP-6482