Magnesium (Mg) is essential for proper bodily functions in living organisms. The content of this nutrient in plants is variable, and its uptake by plants is influenced by both abiotic and biotic factors. The aim of this study was to determine the effect of interactions between spring barley and Italian ryegrass in pure and mixed stands on the Mg content of the aerial biomass and uptake by both plant species under different soil moisture conditions. Three series of a pot experiment were conducted in greenhouse under controlled conditions. The following experimental factors were analyzed: (1) stand type (each plant species was sown in pure and mixed stands), (2) water supply (optimal and reduced by 50%). The Mg content of the aerial biomass of plants was determined in five growth stages (leaf development, tillering, stem elongation, heading, ripening) corresponding to the development of pure-sown barley under optimal water supply conditions. The Mg content was determined by atomic absorption spectrometry, and the Mg uptake was calculated based on the Mg content and dry matter accumulation in plants. Neither a stand type nor the water deficit had a significant effect on the Mg content in the aerial biomass of barley and Italian ryegrass during their growth and development. Both the stand type and water supply significantly affected the Mg uptake by the aerial parts of plants. From emergence to heading, the Mg uptake by spring barley was hindered by water deficit rather than by competition with Italian ryegrass. The responses of Italian ryegrass to water stress and competition with barley varied in the initial growth stages, whereas during later growth stages, the Mg uptake was limited by competition with barley rather than by water deficit.

24.4.2019