Thursday, August 2, 2012
Grand Ballroom
Site specific fertilization (SSF) defines the type and rate of fertilizer needed for individual orchards. This study presents preliminary results (2010–2011) of a medium term project to quantify the effects of SSF on yield, fruit size, quality, and shelf-life of ‘Kent’ mango. Two orchards are used for the study and are located in Acaponeta (irrigated) and San Blas (rain fed) counties, Nayarit, Mexico, respectively. Planting distance in both orchards is 10 x 10 m, about 100 trees/ha. At each orchard, three fertilization treatments were evaluated: 1) Normal rate, which considers the demand of the tree to produce 20 tons/ha; 2) High rate (normal rate + 50 %); 3) Control (no fertilization). The elements supplied in the fertilizer mixture were N, P, K, Ca, Mg, Fe, Mn, Zn, and B. They were applied in July and September, 2010. A factorial design with 20 tree-replications per treatment was used. At full bloom 20 panicles per tree were tagged. Fruit were harvested when they reached 1,800 thermal units (Base temperature = 10 °C). At harvest, yield (kg/tree), fruit size (length, diameter, weight, and caliber), and initial quality (external appearance, skin color, pulp firmness, pulp color, and total soluble solids content) were recorded. Another set of fruit was stored at market simulation conditions (22 ± 2 °C; 75 ± 10% RH) until reaching the consumption ripeness stage. Shelf-life was evaluated periodically and quality was assessed again at consumption time. Significant differences were found for fertilizer treatments, especially for yield and fruit size. The normal dose resulted in bigger fruit when compared to high and control treatments. For initial quality, significant differences were detected for pulp firmness and total soluble solids content, while at consumption differences were detected for pulp color and total soluble solids content, all of them in favor of the normal dose. Fertilization treatments did not affect shelf-life.