Influence of Leaf Nutrition of Some Micronutrients on Absorption of Mentha Plant under Soil Phosphorus Deficiency

Phosphorus is one of the most used fertilizer macronutrients and in calcareous soils of Iran, its absorption is limited. On the other hand, considering the problems caused by the soil use of micronutrients, it is possible to modify the effects of phosphorus deficiency by spraying micronutrients. This study was conducted as factorial in a completely randomized design in three replications to investigate the effect of leaf nutrition of micronutrients (iron, zinc and copper) on the absorption of nutrients of Mentha aquatica L. in phosphorus deficiency conditions. Experimental treatments consisted of no deficiency (control) and two levels of phosphorus deficiency and foliar application of Fe2+, Zn2+ and Cu2+ in concentration of 1 and 2%. Deficient plants showed a significant decrease in P content of root. Spraying Fe2+ and Cu2+ 2% caused increase in P content under deficiency. Foliar nutrition with iron, zinc and copper caused decrease in nitrogen and phosphorus content in deficient plants. Applying zinc and iron as spraying caused increase in NO3− content in shoots and roots. In the present study, spraying zinc, iron and copper caused increase in their contents in shoots and roots of Mentha. Spraying Fe2+ 2% caused increase in P, NO3− and Fe2+ contents in shoots of Mentha plant. The orthogonal comparison results showed that there was a significant difference in nutrients content between foliar application of micronutrients and control and also between foliar application of iron compare to copper and zinc and foliar application of zinc compared to copper in shoots and roots of Mentha. Regarding the obtained results, leaf nutrition of micronutrients as spraying can be mentioned as a suitable suggestion to reduce the effects of macronutrients deficiency, especially phosphorus. It seems that spraying iron and zinc showed the highest effect in absorption of other nutrients in shoots, also spraying copper had the highest effect in roots.