No abstract

We have determined the contents of N, P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn in winter wheat, spring barley, sugar beets and winter rape, as well as in the most common weed species infesting these crops. It was established that the percentage of mineral components in the dry matter of the majority of weeds is higher than in that of the cultivated plants. The most dangerous weed species competing with plants for the investigated nutrients were: <i>Chenopodium album, Cirsium arvense, Convolvulus arvensis, Polygonum convolvulus, Sonchus arvensis</i> and <i>Stellaria media</i>.

The content of N, P₂O₅, K₂O, CaO and MgO was measured in parasitical weeds, as well as in their host plants and in the soil. The soil was also analyzed for its humus content and pH. The statistical analysis of the results justified the ascertation that, on the average, weeds were richer in macroelements then their host plants. In the investigated two groups of plants, both differences as well as similarities in the usage of the mentioned components were found, and the component content in parasites was dependent not only on particular chemical compositions of host plants, but also on soil characteristics