Open access publications in the SLU publication database

The effect of pH, nitrogen concentration and nitrogen form on cadmium (Cd) content in potato has been studied in field experiments, pot experiments and in uptake experiments with
radioactive Cd (109Cd). Two potato varieties were used in the experiments; one low Cd accumulating and one high Cd accumulating variety. The application of nitrogen as
ammonium resulted in a low soil pH and a high cadmium concentration in tubers compared to a balanced nitrogen fertilizer as NPK. This must be due to an increased availability of cadmium in the soil as the uptake experiments showed that cadmium uptake was actually
higher at pH 6.5 compared to pH 4.5 when the availability was constant. The application of calcium nitrate also resulted in a high tuber Cd concentration as compared to NPK, which may be due to calcium ions binding to soil particles and thereby release bound Cd ions into the soil solution. Both the field trials and the uptake experiments showed that both Cd concentration and uptake decreased with increasing nitrogen concentration. Interestingly,there was a linear correlation for both varieties between the Cd concentration in the third leaf and the Cd concentration in tubers at harvest. According to this study, it is best to use a balanced and pH neutral nitrogen fertilizer to avoid Cd accumulation in potato tubers.