Pot experiment was carried out to study the effect of different rates of nitrogen (0, 20, 40 and 60 kg N/fed.) and its two forms (amide and ammonium) with or without zinc at three rates (0, 5, and 10 ppm) on dry matter yield of barely plants (grown on an alluvial and calcareous soils) and their content and uptake of zinc and total nitrogen. The results obtained show that the dry matter yield of barely increased with increasing the rates of applied nitrogen (amide or ammonium). This effect of nitrogen was magnified by addition of zinc. Addition of nitrogen in the ammonium form combined with or without zinc reduced zinc concentration in the plants grown on the alluvial soil, however an opposite effect was noticed on the plants grown on the calcareous soil. Supplying the plants with nitrogen in the amide form resulted in an increase in their content of zinc and this effect became more obvious by addition of zinc. Plant uptake of zinc increased due to addition of nitrogen (in both of its used forms) and zinc. However, the highest rate of zinc (10 ppm) resulted in a decrease in zinc uptake by barely plants when supplying them by the highest rate of nitrogen in the amide form. Total nitrogen content of the plants increased by increasing the rate of the applied nitrogen and zinc addition enlarged this effect.
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