USE OF DILUTE CALCIUM CHLORIDE FOR THE EXTRACTION OF PLANT-AVAILABLE ALUMINUM AND MANGANESE FROM ACID SOIL

Abstract

A method is proposed for the simultaneous extraction of plant-available Al and Mn from acid soils that consists of shaking the soil in 0.02 M CaCl₂ (1:2 ratio) for 1 hr. The method was developed by comparing the amounts of these elements extracted by different concentrations of the salt and by different extraction times with yield and uptake data for barley, turnip rape, and alfalfa grown on 40 acid soils in the greenhouse. Yield response of turnip rape to lime was related to the amounts of both Al and Mn extracted by the proposed method, whereas responses of barley and alfalfa were related only to the amounts of Al. In addition, the yield responses of barley to lime in a series of field experiments were in close agreement with amounts of Al extracted by the method. Use of the method in predicting the need for liming is discussed.