CONTENT AND UPTAKE OF MICROELEMENTS (CU, ZN, MN, FE) BY MAIZE (Zea mays L.) AND ACCOMPANYING WEEDS

A field experiment was conducted in the years 2008– 2010 at the Research Station of the Faculty of Agricultural Sciences, University of Life Sciences in Lublin, on brown soil with slightly acidic pH and average abundance of copper, zinc, manganese, and iron. The experiment was set up in a randomized split-plot design with four replications, with two methods for controlling weed infestation: I. mechanical – weeding of inter-rows twice; II. chemical – the herbicide Afalon Dyspersyjny 450 SC, directly after sowing (a.i. linuron, 900 g × ha). Next, the copper, zinc, manganese and iron content were determined in the maize and dominant weed species. Nutrient uptake from an area of 1 ha and the species specificity coefficient (SSC) were also calculated. All the weed species examined contained more copper in their biomass than maize, but their percentage share in total uptake was small, on average 1.7%. The content of zinc in maize biomass and in the segetal species was similar, except for Cirsium arvense L. which accumulated considerably less zinc than maize as well as the other weed species. The percentage share of weeds in zinc uptake was only 1.4 % of total uptake of this nutrient by the maize crop. Competitiveness of weeds in the accumulation of manganese and iron showed high species specificity. Chenopodium album L. and Galinsoga parviflora Cav. were the most competitive in accumulating manganese, while Cirsium arvense L. showed high ability to accumulate iron, considerably much higher than maize and other weeds species. The share of weeds in total manganese uptake was relatively large, on average 7.2% for the experiment.