A Survey of the Mineral Nutrition Status

 of Valencia Orange in Florida

 By
 R. C. J. Koo, H. J. REITZ AND J. W. SITES

 INTRODUCTION
 Fertilization of citrus trees is the largest single expense in
producing citrus in Florida. Many approaches have been tried
to determine guides for applying the most economical amounts
of fertilizers. One of the means used most extensively to study
this problem has been leaf analysis. There is considerable in-
formation available from experimental plots showing the range
of the various elements in citrus leaves from trees growing with
various supplies of nutrients. The purpose of this survey was
to determine the nutrient content of Valencia orange leaves and
fruit from a large number of commercial groves, and compare
the levels found with those obtained from experimental plots.
 A rather comprehensive review of the factors which may in-
fluence leaf composition, and their relation to deficiency and tox-
icity symptoms, yield and fruit quality has been prepared by Reu-
ther and Smith (17).2 Reuther et al. (20) compared the mineral
composition of Valencia orange leaves from central Florida
with the other citrus producing areas of the United States and
found that, with the exception of calcium and copper, all the ele-
ments studied were higher in central Florida than elsewhere. In
a similar study for Valencia orange leaves from the Indian River
section, Reitz and Long (13) found closer similarity between
leaves from the Indian River area and other citrus producing
sections than between Indian River and central Florida. In
both studies no attempt was made to correlate leaf analysis with
fruit quality characteristics or yield.
 Fragmentary information (2,4,7,25) available on the min-
eral composition of whole fruit in Florida indicated that the
possibility of using samples of whole fruit as an index to the
mineral nutrition of the entire tree is worthy of investigation.

 SRespectively Assistant Horticulturist and Horticulturist-in-Charge,
Citrus Experiment Station, Lake Alfred; Head, Fruit Crops Department,
University of Florida.
 Italic figures in parentheses refer to Literature Cited.