Cadmium uptake of winter and spring wheat cultivars depending on the chemical form of potassium fertilizer

Abstract

The aim of the studies was to define the differences between wheat cultivars (both winter and spring forms) in cadmium uptake depending on potassium fertilizer form and soil contamination level. The experiments were set up in plastic pots in four replications. The pots were filled up with 9 kg of soil. Four spring wheat cultivars (Eta, Hera, Igna, Sigma) and four winter wheat cultivars (Jawa, Mikon, Olcha, Wilga) were grown. Three forms of potassium fertilizer (KCl, K₂SO₄, KH₂PO₄) were taken into consideration. Two independent experiments were conducted: on uncontaminated soil and on the soil contaminated with 4 mg Cd kg^-1. NPK fertilization doses amounted to 2.4, 0.9, and 2.4 g per pot, respectively. The soil was polluted by CdSO₄ addition. Concentration of Cd in grain was measured using flame atomic absorption spectroscopy (AAS). The accumulation of cadmium in grain of spring and winter wheat was significantly differentiated by potassium fertilizer form. Under KCl fertilization soil cadmium content in spring wheat grain on uncontaminated was twice as high as after K2SO4 and KH2PO4 fertilization. On the soil contaminated with CdSO₄ the cadmium content in grain was on the same level under K₂SO₄ and KCl fertilization, but significantly higher than after KH₂PO₄ application. The wheat cultivars differed significantly in cadmium uptake. A soil higher trace element content was found on the uncontaminated in ‘Eta’ and ‘Sigma’ cultivars, independently of potassium fertilizer form. A significant interaction between cultivars and potassium fertilizer form was found. For example, cultivars ‘Eta’ and ‘Sigma’ accumulated Cd more intensively under KCl fertilization than ‘Hera’ and ‘Igna’ cultivars.