Composition of Florida-Grown Vegetables 23

 The peat soils of the Belle Glade area contained large quan-
tities of organic nitrogen, exchangeable calcium 3 and mag-
nesium. This was reflected in the composition of cabbage, as
shown in Table 2. However, these soils were relatively low in
dilute acid-soluble phosphorus and exchangeable potassium, but
produced cabbage which averaged second highest in these 2
elements. A high level of organic matter apparently favored
the availability of phosphorus and iron and possibly potassium.
Cabbage containing the lowest concentration of phosphorus was
grown at Bradenton on soils which contained a relatively high
amount of dilute acid-soluble phosphorus. Potassium followed
the same trend in that it was relatively high in the soils from
the Bradenton area on which cabbage was grown, yet the cab-
bage was low in potassium.
 The composition of green beans (Table 3) did not vary as
much as the composition of cabbage, although the soil types on
which beans were grown represented a wider range in chemical
composition. Seed-bearing portions of plants are known to be
more constant in composition than leaves.
 The calcium and magnesium contents of beans were definitely
 associated with soil type. Calcium was highest in beans grown
 on the marl soils at Homestead and second highest in those
 grown in the Belle Glade area on organic soils also containing
 large quantities of calcium. The highest average concentration
 of phosphorus was found in beans grown on calcareous soils.
 These soils were low in extent of dilute acid-soluble phosphorus.
 This is probably the result of neutralization of the extracting
 acid by the lime, rather than a true low quantity of soluble phos-
 phorus. The amount of carbonic acid-soluble phosphorus found
 in these soils substantiates this contention. The pH of the
 calcareous soils was above neutral but the organic matter con-
 tent of these soils was relatively high and may have aided in
 phosphorus assimilation by the plants. On the other hand,
 phosphorus was below average in samples from the Belle Glade
 area, which is the reverse of the findings with respect to cabbage.
 The iron concentration in beans averaged highest for those
 grown on slightly to moderately acid organic soils, next highest
 in beans grown on mildly acid sands and generally lowest in
 those grown on calcareous soils. This is in agreement with

 Millequivalents of exchangeable bases exceed base exchange capacity
 in e-rt-in instances because of the solubility of lime in the extracting
 reagent.