International Potash Institute
K in the Literature

Potassium is an essential plant nutrient and adequate K fertilisation is must for successful crop production. Current recommendations for K fertilisation are based on exchangeable-K in surface 0-15 cm soil. However, available reports suggest that non-exchangeable-K and sub-soil K contributes significantly towards K uptake by crops. These factors therefore need to be taken into account along with exchangeable-K for making fertiliser recommendations for crops. Red and lateritic soils, which occur in east, northeast and southern India, are the poorest in K and need K fertilisation beyond the standard N:P:K ration 4:2:1. Black soils, which have a high exchangeable-K content are poor in non-exchangeable-K and total K and therefore need adequate K fertilisation to prevent K mining of soils.