Abstract
An experiment was conducted during the 1997/98 through 1999/2000 seasons in a block of 'Valencia' orange located in Martin County to determine the effects of foliar nutritional sprays on fruit size, solids production, and fruit number. The trees were either left untreated or had foliar applications of potassium nitrate (KNO[sub3]), monopotassium phosphate (MPK), calcium nitrate [Ca(NO[sub3])[sub2]], KNO[sub3] + MPK, or Ca(NO[sub3])[sub2] + Nutriphite in replicated field experiments. Cumulative effects were assessed by maintaining the same treatments on each tree for three seasons. Foliar sprays were typically made with each material in February, April, and July/August. Fruit were analyzed for maturity as they approached normal harvest times. The treatment effects were measured by counting the number of fruit and determining the size distribution for six trees in each plot at time of harvest. In each season, trees receiving KNO[sub3] or MKP applications had more fruit per tree and larger fruit than control trees. Over the 3 years, trees receiving the KNO[sub3] or MPK applications had 24-29% more fruit per tree, averaged 28% more boxes per tree, and had 25% higher total pound solids per tree than the control treatment. Total gross returns would be 24% higher for processed fruit and 28% higher for packed fruit for the KNO[sub3] and MKP treatments compared with the control.
