The ESP of sodic alkaline soil is

Sodic or alkali soils are clay soils with high pH, a poor soil structure and a low infiltration capacity. Alkali soils owe their unfavorable physio-chemical properties mainly to the dominating presence of sodium carbonate, which causes soil to dwell, and is difficult to settle.
Sodic soils are those which have an exchangeable sodium percentage (ESP) of more than 15. Excess to ESP has an adverse effect on the physical and nutritional properties of the soil.