EVALUATION OF APPLICATION METHODS AND RATES OF ZINC AND BORON ON NITROGEN,PHOSPHORUS AND POTASSIUM CONTENTS OF MAIZE LEAF

Plant analysis can be a useful tool in determining the general nutritional status of crops during the growing season. For this reason, a field experiment was conducted in the Fars province of Iran during 2008 season to evaluate the concentrations of nitrogen (N), phosphorus (P) and potassium (K) in maize leaf as affected by zinc sulfate and boric acid. Treatments were arranged in a randomized complete block design with two factors and three replications. Factor one included four levels of B (0, 3 and 6 kg ha^?1 B added to the soil and B foliar spray with a 0.3% concentration); factor two consisted of five levels of zinc (Zn) (0, 8, 16 and 24 kg ha^?1 Zn added to the soil and Zn foliar spray with a 0.5% concentration). The results of this work showed that the main effect of Zn and B levels and interaction of Zn–B on the leaf N and P concentrations was insignificant. A synergism was seen between Zn and K and also between B and K. The presence of a high amount of Zn or B in the soil prevented from increase of leaf K content, by B or Zn application, respectively.