EFFECTS OF CONTROLLED-RELEASE FERTILIZER ON FRUIT YIELD AND QUALITY OF CLEMENTINE CITRUS TREES

Abstract

A field experiment was carried out in a commercial citrus orchard on mature Clementine trees (Citrus reticulata Swingle). The trees received the same fertilization amount but by two different fertilization methods. On one plot of one-half an hectare, the trees were fertilized with a slow-release fertilizer (17N-12P-18K +2Mg) buried 10 cm deep under drip emitters at the beginning of the spring tree flush growth (first week of April). A second application was made at the beginning of the autumn tree flush growth (end of August) with another slow-release fertilizer formulation (13N-5P-27K +2Mg). On the other half a hectare plot, the trees were fertigated with the same quantity of nutrients as the first plot but distributed throughout the growing season. The results showed no differential treatment effect on yield. Fruit weight was higher with the controlled-release fertilizer producing more fruit as Extra Class Size. The fruit quality was similar between the two fertilizer methods.