Field studies of cadmium in potatoes (Solanum tuberosum L.). Response of cvv. Russet Burbank and Kennebec to two double superphosphates of different cadmium concentration

Abstract

Separate field experiments were conducted with Russet Burbank and Kennebec potatoes on a basaltic krasnozem where tuber cadmium (Cd) responses were examined over three rates of banded phosphorus (P), supplied as double superphosphate (DSP) containing either 15 or 90 mg Cd kg-1. In both cultivars, tuber Cd concentrations increased with rate of DSP. This response was due more to the amount of P supplied in the DSP than the amount of Cd supplied in the DSP and may be a result of banded P encouraging root proliferation in the fertilizer band. Even with DSP at 15 mg Cd kg-1, Cd additions at rates of DSP needed for high yields were 6-20 times higher than corresponding rates of Cd removal in tubers. Examination of data from all studies of Cd in Russet Burbank on Tasmanian krasnozems showed a significant relationship between petiole and tuber Cd concentrations, but the estimation of a petiole concentration associated with the critical tuber Cd concentration in Australia was subject to unacceptable uncertainty due to variation between sites.