6 Florida Agricultural Experiment Station

sampling, preparation and analysis must be reasonably uniform
in order that comparisons be valid.
 It was the purpose of this investigation to determine the
ranges in mineral composition of several commercially grown
vegetables in Florida, and to correlate them with cultural prac-
tices, locality, soil type and soil composition.

 Review of Literature
 Beeson (1) has published a comprehensive compilation of data
showing the mineral composition of crops with particular refer-
ence to the soils in which they were grown. He recognized and
discussed some of the fallacies involved in sampling and prep-
aration of plant samples for analysis. Sherman (18) compiled
analyses of many types of foodstuffs. He recognized the vari-
ation in composition between plant parts such as the cabbage
head and the outer green leaves. Peterson and Elvehjem (16)
have pointed out the low percentage of iron in the heads of
cabbage, celery and lettuce as compared with the outer leaves
and stems of these vegetables. Cowell (5) showed that the
calcium content of the outer leaves of cabbage is 20 to 30 times
that of the head. He pointed out that the leaves are a richer
source of calcium than any other food, with the possible ex-
ception of cheese.
 Elmendorf and Pierce (8) stressed the importance of chemical
analysis in food metabolism studies. They found that plants
grown on different soil types under varying conditions of fer-
tilization, culture and climate exhibited marked differences in
composition. Coleman and Ruprecht (4) concluded that, under
Florida conditions, complete fertilizers exert very little influence
on the composition of the crop when used in optimum amounts
for crop production. Eisenmenger and Kucinski (7) studied
the effect of soil treatment on calcium and magnesium content
of plants. They concluded that further experimentation might
develop procedures by which the mineral content of food plants
may be partially controlled by cultural methods so that the
mineral requirements of animals could be more adequately
satisfied.
 The mineral content of plants apparently varies considerably
with the age of the plant and the season of the year. Bennett
(2) found that iron increased more rapidly in leaves during
early growth than after full size was reached. Sheets et al. (17)
reported significant differences in the calcium and phosphorus