A SURVEY OF MINERAL-COMPOSITION OF WEED SEEDS

Seeds of 43 weed species from 13 families were collected from mature p lants in barley (Hordeum vulgare L.), bread wheat (Triticum aestivum L .), durum wheat (T. durum Desf.) and oat (Avena sativa L.) fields in s emi-arid regions of Morocco and analysed for their N, P, K, Ca, Na, Fe and Zn contents. The results showed that 39 weeds had similar or high er N content than wheat grain. Species with high P concentrations incl uded Diplotaxis tenuisiliqua Delile (0.79%). The highest Ca and Na con centrations were found in Beta macrocarpa Guss. (2.37% and 0.55% respe ctively). The highest Fe and Zn contents were observed in Chenopodium murale L. (0.059% and 0.034% respectively). It is concluded that weeds that may not be highly competitive with cereal crops may be left in t he field and harvested with the cereals. From a nutritional point of v iew, there is no need to discard seeds of these weeds from grain cerea ls.