The objective of the study was to establish the effect of component share in mixtures and harvest date on concentrations of selected heavy metals in the green fodder of field pea, oat, and their mixtures. The research hypothesis assumed that the cultivation of peas and oats in pure sowing, and in mixtures will also allow to choose combinations from which the forage will have the lowest content of heavy metals. Field research was conducted at the Zawady Experimental Farm (52° 03' 39″ N, 22° 33' 80″ E) which belongs to Siedlce University of Natural Sciences and Humanities. Two factors were tested in the study: I-component share in the mixture: field pea-pure stand 100%, oat-pure stand 100%, field pea 75% + oat 25%, field pea 50% + oat 50%, field pea 25% + oat 75%; II-harvest date: field pea flowering stage, field pea flat pod stage. Plant material was sampled to determine the following elements: Cu, Zn, Cd, Pb, Cr, and Ni. The results of the study demonstrated that field pea grown in pure stand had the highest copper and zinc contents, and the lowest chromium and nickel contents. Field pea mixed with oat significantly reduced heavy metal content in green fodder. Cadmium and lead contents in the green fodder of field pea/oat mixtures were too low to be determined by means of the spectrometer Perkin Elmer Optima 8300. Regular checks of heavy metal contents are recommended in spite of their low amounts in the green fodder of field pea/oat mixtures.
Keywords: Avena sativa; Harvest date; Heavy metals; Mixture; Pisum sativum.