Fertilization increased fine root production in the surface
S15 cm of the soil profile. These fine roots accumulated large
levels of Al as a result of root expansion into the spodic horizon.
Very little of the Al was translocated into the above-ground
biomass.
 Total elemental uptake data indicated that a maximum of
 13% of the applied P fertilizer can be accounted for in the 5-
 year-old tree biomass.
 Fertilizing slash and loblolly pines with diammonium phos-
 phate will not adequately substitute for water table control in
 flatwood soils, such as this Leon fine sand. A small growth in-
 crease may be obtained from fertilization of these soils without
 any water control. However, water table treatments that con-
 fined the root systems to the surface soils (46-cm and fluctuating
 water tables) resulted in the greatest response to fertilizers.



 ACKNOWLEDGMENTS
 This work was supported in part by the Cooperative Research in Forest
 Fertilization (CRIFF) program. The authors are indebted to Dr. W. K.
 Robertson for his assistance in devising the system of harvest of tree roots,
 to Dr. L. C. Hammond for the installation of the irrigation-drainage sys-
 tem, and to Mr. F. R. Humphreys for the soil analyses.


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