Florida Agricultural Experiment Stations


indicate older groves, which may be another factor. In the ab-
sence of controlled conditions, the data should not be interpreted
as indicating soil copper was related to fruit production, espe-
cially in view of the complications which may arise from high
copper content in soils (18). The potassium content of both
leaf and fruit varied directly with the soil copper content, while
the magnesium content showed an inverse relationship.

TABLE 21.-THE AVERAGE FRUIT PRODUCTION AND MINERAL CONTENTS OF
 LEAF AND FRUIT AT DIFFERENT LEVELS OF COPPER IN SOIL.
 SAver- Nitro-
Copper Groves age gen Fruit Leaf Soil
 Yield Applied I N K Mg K I Mg P
Lbs./A. No. Boxes/ Lbs./A. % / % % % %c Lbs./
 A. A.
 50 .... 32 363 198 0.85 1.27 0.118 1.78 0.463 350
 100 ...... 56 404 235 0.91 1.34 0.111 1.86 0.415 462
 200 ...... 50 425 228 0.93 1.38 0.108 1.87 0.397 531
 I I
Statistical
 significance ** **

 INFLUENCE OF SPRAY AND DUST PROGRAM
 Since the present study is concerned primarily with the min-
eral nutrition status of the Valencia orange, a detailed study of
the influence of spray and dust programs was not attempted. As
an exploratory study on the possible effects of certain spray ma-
terials on fruit and leaf characteristics, all of the groves were
divided into three groups: those using oil, oil-parathion and para-
thion. No significant difference was found in fruit production,
fruit quality or mineral composition of leaf and fruit that could
be attributed directly to any of these sprays. If any influence
did exist, it was obscured by other factors.
 Since the annual rainfall in 1955 was considerably below
normal, with the rainfall deficit varying widely in different sec-
tions of the citrus belt, the groves were further divided into two
groups according to moisture deficit. Groves in group "A" are
those in which soil moisture conditions were near the long-time
average, either through rainfall alone or with irrigation. Group
"B" represented those where the moisture deficit was appreci-
able. When the groves were classified on that basis (Table 22),
no difference was observed in fruit production from the use of
different scalicides as long as the supply of moisture was "ade-