Availability of Accumulated Nutrients.-Soil pH, organic
matter, and ammonium acetate (pH 4.8) extractable nutrients as
averages of four selected locations replicationss) on the Phase
3 experimental area for March 22, 1971, at initiation of this
supplementary study and in October 1971, 1972, and 1973 are
shown in Table 8. These data are in general agreement with
those in Table 7 with respect to nutrient concentrations. Higher
levels of P and K in the initial spring samples were caused by
fertilization during the preceding November. These nutrients
had not been removed by plant absorption, leaching, or reactions
with the soil which reduce solubility in ammonium acetate (pH
4.8). Subsequently, the plot areas were covered with a plastic
sheet at time of fall fertilization to prevent contamination.
 White clover was an essential part of the grazed experiments
 in Phase 3 because it provided forage during early spring and
 symbiotically fixed N for grass growth during the summer. Since
 fertilizer was not fall-applied in the study of residual nutrient
 availability, growth of clover was poor.
 All plant samples from the 3-year study of residual nutrient

Table 8.-pH Organic Matter and Ammonium Acetate (pH 4.8) Ex-
 tractable Nutrients from Limed and Continuously Fertilized
 Flatwoods Surface Soil Planted to White Clover and Pensa-
 cola Bahiagrass.
 NH4OAc(pH 4.8) extractable
Treatments pH O.M. P K Ca Mg
 % Ib/acre
 Pre-experimental, March 22, 1971
 Avg. 5.9 4.95 26.2 132 3080 156
 October 8, 1971
 1 5.6 11.2 50 2960 130
 2 5.5 15.8 26 2360 92
 3 5.4 23.6 60 2780 178
 October 6, 1972
 1 5.9 9.2 22 2300 70
 2 5.9 8.0 16 1820 42
 3 5.6 9.0 28 2220 90
 September 16, 1973
 1 5.9 9.4 16 1800 38
 2 5.9 7.0 14 1820 12
 3 6.0 6.2 16 1660 68
 *Treatments 1, 2, and 3 were superimposed at selected locations in 1971 on
 Programs 1, 2, and 3. The treatments were (1) none, (2) N only, and (3) all
 nutrients except Ca.