EFFECTIVENESS OF LIMING TO MINIMIZE UPTAKE OF CADMIUM BY WHEAT AND BARLEY-GRAIN GROWN IN THE FIELD

The effects of soil pH on cadmium (Cd) concentration in wheat and barl ey grain were determined from 8 field experiments in the Rutherglen (V ictoria) and Wagga Wagga (New South Wales) regions of south-eastern Au stralia. Generally, raising soil pH(Ca) from 4.0 to 5.0 using lime dec reased Cd concentration in the grain. However, the response was variab le between sites and years, with the greatest variation occurring betw een years. At those sites where there were statistically significant d ecreases in Cd concentration with increasing pH, the rate of decrease was small. The Cd concentration exceeded the maximum permissible conce ntration (MPC) of 0.05 mg/kg in barley grain at 3 sites and in wheat a t 1 site. In some cases, raising soil pH(Ca) to 6.0 was not sufficient to decrease Cd concentration in grain below the MPC and raising soil pH above this value would not be considered economically viable in man y areas.