The effect of application of potassium humate on the content of cadmium, zinc and arsenic in plants

To study the effect of potassium humate (Tab. I) on the yield of cultivated crops and accumulation of cadmium (Cd), zinc (Zn) and arsenic (As) in plant biomass, pot trial was established with silage maize, haylage oat, poppy and spring barley. Three different contaminated soils from the locations Cerveny Ujezd, Prestanov and Kbely (Tab. II) were used in the trial. Potassium humate was applied by spray during the growing season of cultivated crops at a dose of 20 mg in 20 mi solution per pot. Agrotechnical data of the trial are summarized in Tab. III. The yield of cultivated crops was not affected statistically significantly by application of humate. It was ranged between 92 and 114% of the yield of control treatments (Tab. IV). It was evident from investigation of accumulation of Cd in biomass of cultivated crops that with its increase of concentration in soil increased also its content in tissues of plants. Spraying of humate resulted in the decrease of the Cd content in all crops, except poppy where in turn a significant growth of concentration of this element was observed (in seed by Is to 29% and capsule by 32 to 53%) (Fig. 1). Merely in acid soil the content of Cd decreased in this crop. Similarly to the case of Cd, humate application had an effect on the decrease of Zn concentration in barley grain and straw and in haylage oat (Pig. 2). In maize and poppy Zn content increased. The most marked increase by 171% was determined in capsule in soil of Kbely. As content in biomass of crops was investigated in the first and last year of experiment. In both cultivated crops (maize and barley) after humate application its concentration in biomass (Pig. 3) increased. Results of the experiment confirmed the positive effect of humate on the decrease of Cd and Zn content in cereals and its different effect on uptake of these elements by poppy. The increase of As concentration in tissues of investigated crops was found as well.