POTASSIUM IN THE SOILS OF NEW-ZEALAND - A REVIEW

This paper reviews current information about potassium (K) in the soil s of New Zealand, based on work conducted since the 1920s. The forms o f K existing in soils are discussed and related to the K status of the genetic soil groups. The methods used in New Zealand to assess K-supp lying power, K-releasing power, and plant-available K are discussed. T he historical development of the methods for computing the K fertilise r requirements of pastures and crops in New Zealand is reviewed with e mphasis on the Computerised Fertiliser Advisory Service (CFAS) establi shed in 1984. The CFAS model is discussed and amendments are suggested .