Table 3.


Levels of 0.5N acetic acid-extractable potassium in the organic
soils of the Everglades*.


HAc-extractable K Percent of total samples
 Lbs/A Virgin Cropped
 0-40 41.5 14.6
 41-80 41.6 24.6
 81-120 3.9 21.6
 121-160 1.5 14.6
 161-300 4.5 9.5
 > 300 4.o 5.1


 Summary of analyses of 200 samples from virgin, and 4000. samples
 from cropped, organic soils analyzed by soil testing laboratory,
 Everglades Experiment Station, 1953-57.

 The last factor involved in a soil testing program is the fertilizer
recommendation. It has been found experimentally that for organic soils in the
Everglades approximately 20 pounds P205 per acre must be applied in fertilizer
for each pound of phosphorus that a soil is below the necessary minimum accord-
ing to the soil test. Similarly, two pounds K20 per acre must be applied for
each pound that a soil is deficient in potassium. There are, of course, many
factors to consider in arriving at a fertilizer recommendation, but the basic
recommendations for phosphorus and potassium are worked out on the basis of the
minimum values previously discussed, and the above factors for converting soil
test results into fertilizer needs.
 Acidity is a little more difficult to interpret quantitatively than phos-
phorus and potassium levels. As shown in Table 4, nearly 90 percent of the
organic soils in the Everglades range in pH between 5.1 and 6.6. Limestone is
not recommended on such soils. Conversely, minor element deficiencies often
appear when the soil pH is above 6, so sulfur for lowering the pH is often
applied in much the same manner that lime would be used in other areas.

Table 4. Acidity levels in the organic soils of the Everglades*.


 Percent of total samples
 H .irgin Cropped

 5.0 or below 5.0 5.4
 5.1 5.6 22.0 25.1
 5.7 6.0 26.2 35.0
 6.1 6.6 39.8 26.2
 6.7 or above 7.0 8.3

 Summary of analyses of 200 samples from virgin, and 000 samples
 from cropped, organic soils analyzed by soil testing laboratory,
 Everglades Experiment Station, 1953-57,