an imbalance in the root-top ratio, and toxic decomposition
products from dead roots may further limit growth (10).
 Presented in this report are research results on controlling
the water table and its effect on nutrient availability and on the
growth and development of slash (Pinus elliottii var. elliottii
Engelm.) and loblolly (Pinus taeda L.) pines in the flatwoods
of the Atlantic and Gulf Coastal Plains.

 MATERIALS AND METHODS
Field Experiment
 A system involving clay tile drains and a deep-well pump
was used to control the water table in two areas of Leon fine
sand. The free water level was maintained at approximately
46 cm from the soil surface in one area and 92 cm in the other
area for five years. In a third (check) area the water table was
allowed to fluctuate normally.3 These areas were separated from
each other by about 50 m to mimimize the effect of water control
in one area on that of another area. The pump was automatically
activated and water was pumped into the tiles when the water
table began to fall during dry periods. The same system of tiles
used for sub-surface irrigation was used to drain the controlled
area during periods of excess rainfall.
 Rainfall at the experimental area is summarized in centi-
meters per months for the five year test period as follows:

 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Total
1964 22.3 18.0 5.9 7.3 6.7 7.9 20.4 31.9 28.5 5.6 7.3 14.9 176.7
1965 4.3 16.4 13.8 3.3 0.2 29.5 16.6 21.3 16.9 4.4 2.9 12.3 141.9
1966 9.8 13.7 5.8 4.8 21.5 12.7 12.4 27.9 19.8 3.8 1.0 3.2 136.6
1967 7.9 14.2 2.1 3.7 15.7 18.1 10.6 23.5 3.3 1.0 2.4 14.7 117.3
1968 1.2 5.4 3.1 2.4 18.1 25.8 20.0 33.8 10.1 7.8 6.4 2.5 136.6

 Three replications of four treatments were established in
 each of the three areas, giving a total of 36 plots. Treatments
 consisted of two Southern pine species, slash and loblolly, and
 two application rates of diammonium phosphate (18-46-0), 0
 and 392 kg/ha, in factorial arrangement. The 30 pine seedlings
 were planted at a spacing of 1.2 m by 1.2 m in individual plots of

 3The natural water table for the Leon soil is at depths of 38 to 76 cm
 for 4 or 5 months each year, and it is within depths of 100 cm for periods
 of more than 9 months during most years It rises to less than 38 cm for
 less than 60 days during periods of high rainfall and recedes to depths of
 more than 76 cm during some dry seasons.