Effect of fertigation on the 'Manzanilla de Sevilla' table olive quality before and after "Spanish-style" green processing

Abstract

Table olive quality was analyzed in adult 'Manzanilla de Sevilla' olive trees subjected to different N-P-K fertigation treatments through five years (1999-2003). A randomized block design with four fertigation treatments was established: irrigated without fertilizer (control), and T200, T400, and T600 treatments, in which each tree was respectively fertigated with 200, 400, and 600 g N per irrigation season of a complex 4N-1P-3K fertilizer applied daily. Fruit yield and fruit physical characteristics and chemical composition were studied in 2002 and 2003. Fruit analysis realized in 2002 showed that the fruit pulp/stone ratio and water content increased with the amount of applied fertilizer. In 2003, a similar trend was found for fruit yield, weight, pulp/stone ratio, volume, longitudinal and transversal diameters, and fruit water and potassium concentrations. On the contrary, the concentration of reducing sugars; Ca, Na, and B; and the fruit texture decreased linearly with the fertilizer dose in 2003. No differences between treatments in fruit and stone shape, or stone volume or polyphenols concentration were found. On the other hand, the effect of the treatments on fruit browning damage was studied in 2003, as well as the fruit quality after "Spanish-style" green processing. In spite of the differences in fruit composition and texture, the fertigation treatments did not affect browning damage. After Spanish-style processing, differences between treatments in fruit weight and texture were again observed, but color, brown spots, and blistering incidence were not modified.