Two field experiments were conducted in 2005/2006 and 2006/2007 in the region of Tag AL-Ezz, Agricultural Research Station Farm, Dakahlia Governorate, Agricultural Research Center, Egypt to evaluate the effect of nitrogen rates and micronutrients fertilizers on wheat plant growth, some physiological and anatomical parameters and yield.
Application of micronutrients combined mixture under high nitrogen rate produced the highest values of plant growth, yield and physiological characteristics compared with other treatments. The second rank best treatment was observed with applications of Zn, then Mn treatment. Cu and Fe treatments were equal in its effect and the differences between them were insignificant in the most cases. Application of nitrogen rate up to 90 kg/fed increased gradually all studied characters.
Anatomically, application of combined mixtures of micronutrients under high nitrogen rate increased significantly all anatomical characteristics of flag leaf or culm, in particular, number of vascular bundles and thickness of mechanical tissue in culm as well as dimension of vascular bundles, diameter of metaxylem vessels, and thickness of epidermis in both flag leaf and culm. Furthermore, thickness of mesophyll parenchyma and midrib region in flag leaf was also increased.
In conclusion, the obtained results show that foliar application of combined mixture of studied micronutrients (Cu, Mn, Fe and Zn) at the rate of 500 ppm from each under moderate (recommended rate) or high rate of nitrogen fertilizer (70 or 90 kg N/fed) can be recommended to maximize wheat growth and grain yield per main spike and per plant.