| heal.abstract |
As nitrogen (N) fertilization is considered incompatible with oriental tobacco agricultural practice, we studied the influence of N fertilization [no fertilization or ammonium nitrate (NH4NO3) applied at either 50 or 100 kg N ha-1], the growth stage (plant age) and the stalk position (basal, middle, and upper) on the macronutrient phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) concentration distribution in leaves of the oriental tobacco cv. Myrodata Agriniou. The distribution profiles of leaf P showed an increasing trend from the lower to the upper nodes in all treatments during the vegetative stage up to the fruit set while almost uniform profiles were detected after that. Leaf K, Ca, and Mg accumulation profiles showed decreasing trends from the base to the top over the season. All of the examined macronutrients were accumulated in the lower leaves of the higher fertilized plants late in the season. Leaf dry matter accumulation increased by N fertilization and plant age, and decreased by stalk position. Leaf P concentration increased with N fertilization and stalk position and decreased with plant age. Leaf K concentration decreased with N fertilization, plant age, and stalk position while leaf Ca and Mg concentrations decreased with N fertilization and increased with plant age and stalk position. The interaction of N fertilization x stalk position affected with a weaker strength leaf K, Ca, and Mg and did not affect leaf P. The interaction of N fertilization x plant age x stalk position had a strong effect on leaf K and Ca, and did not affect leaf P and Mg concentrations. Stem P, Ca, and Mg concentrations were lower and K concentration was higher than in the leaves. Calcium and Mg concentration dependence from N fertilization was weaker for leaves than for stems. Stem P and K concentrations were reduced with plant age. Stem Ca concentration did not change while stem Mg concentration was significantly reduced with plant age. Stem concentrations of all the examined nutrient elements significantly increased at higher nodes. |
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