A pot experiment was conducted, in a greenhouse, at Hisar, India, using a sandy soil deficient in nitrogen and copper, to study the effects of various levels of N and Cu on the dry matter yield and the N and Cu contents of wheat (Triticum aestivum L.).
The sources of nitrogen used were Ca(NO3)2, NH4C1 and NH4NO 3 applied in amounts necessary to establish 120ppm of soil nitrogen and using a control (0ppm N). Copper was applied, as copper chloride, to give soil Cu levels of 0, 5, 10 and 20ppm. In general, dry matter yields, N and Cu concentrations in shoots and roots and available soil-N after harvest of the plants, followed the order Ca(NO3) > NH4NO 3 > NH4CI. Up to a level of 5 ppm Cu, the dry matter yields of shoots and roots increased, but decreased at higher levels of Cu. Increasing Cu levels significantly decreased the available soil-nitrogen after harvest and also the concentration of N in the plants. At the same time the concentration of Cu in shoots and roots and available Cu in the soil was increased.
Nitrogen and copper were found to have a mutually antagonistic effect on each other's concentration in the plants. The antagonism was greater with NH4 + sources than with NO 3-compounds.