DEVELOPMENT AND VERIFICATION OF A QUICK TEST FOR THE DIAGNOSIS OF ALUMINUM TOXICITY ON THE DEEP YELLOW EARTHS OF WESTERN-AUSTRALIA

A quick test for estimating phytotoxic aluminium (Al) has been develop ed for the deep yellow earths of Western Australia. The method is base d on a visual assessment of Al extracted by 0.005 M potassium chloride , using pyrocatechol violet as a colorimetric reagent, combined with a measure of electrical conductivity (EC). Quick test measurements were compared with wheat yields from 52 sites to determine if the method c ould distinguish between Al toxic and Al non-toxic subsoils. A ratio o f [Al]:EC was a better predictor of grain yield than [Al] alone.