Florida Agricultural Experiment Stations


minor elements by most of the growers corresponded closely to
recommendations.
 5. Over 80 percent of the groves had a soil reaction ranging
between pH 5.4 and 6.2, which is generally accepted as satis-
factory for growing citrus on acid sandy soil. Both the extract-
able calcium and magnesium contents of the soil varied directly
with the soil reaction, whether dolomite or calcium limestone was
used as the amendment. Soil reaction seemed to affect the mag-
nesium content of leaf and fruit more than other elements.
Highest magnesium content was found in the proximity of pH 5.9.
 6. The groves were well distributed among the different
ranges of soil copper content. The influence of soil copper on
fruit quality was of no practical importance. The available
phosphorus content of soil varied directly with copper. Potas-
sium and magnesium contents in leaf and fruit were affected by
soil copper content.
 7. Records showed that growers followed closely the recom-
mendations with respect to timing and dosages in their spray and
dust schedule. A comparison of leaf analysis and fruit quality
in relation to use of the common scalicides (oil, oil-parathion and
parathion) did not reveal any significant effects, but production
was somewhat curtailed in groves sprayed with oil where the
supply of soil moisture may have been inadequate.
 8. Rainfall in 1955 was considerably below normal. Supple-
 mental irrigation where adequately applied was highly benefi-
 cial to fruit production. The majority of the irrigated groves
 did not receive enough irrigation, which was reflected in lower
 yields. Only groves that were heavily irrigated were able to
 uphold the fruit production records of previous years. Increased
 yield due to irrigation was less pronounced where the rainfall
 deficit was smaller and the distribution more favorable.
 9. Fruit quality was more closely related to the mineral com-
 position of fruit than that of the leaf. It seems desirable to set
 up standards of fruit composition for control of fruit quality, in
 view of the poor correlation between fruit quality and mineral
 elements used in the fertilizer.
 10. The practical application and limitations of leaf, fruit
 and soil analyses were discussed.