Foliar fertilization with zinc and manganese in �??Valencia late�?? orange orchards

Abstract

The experiment was performed in a commercial orchard in Corrientes, Argentina, during three campaigns 2006 to 2009. The aim of this work consisted to evaluate sweet orange �??Valencia late�?? response to the foliar applications of Zn and Mn, with the purpose of defining nutritional management practices. Experimental design was a completely randomized blocks with four replications. Seven treatments were tested, different doses of Zn and Mn, alone or in combination, plus a control. Foliar concentration of Zn and Mn (ppm) were determined on samples from leaf taken in the month March (fruiting). At harvest were determined total production (kg plant-1) and quality, defined by: fruit diameter (mm), juice percentage (%), total acidity (%), total soluble solids (ºBrix) and color (visual scale). Analysis of variance and Duncan test (? = 0,05) were applied for yield and treatments were characterized respect yield and fruit quality with principal component analysis. Differences in average yields between treatments and between campaigns were significant, there was no significant interaction between treatments and campaigns. The sweet orange �??Valencia late�?? response to the foliar applications of Zn alone or combined with Mn significantly increased yields. Foliar applications of Zn and Mn positively influenced the quality of the fruits, being their values within the Argentine Legal Standards of maturity to orange. Applications Zn and Mn alone or in combination had no effect on the color of the fruit.