tically by white clover, but a substantial amount was evidently
mineralized in these soils where organic matter and N had accu-
mulated during the previous 19 years of white clover-grass pro-
duction. Uptake of K was also large compared to surface soil sup-
ply (Table 10). Potassium extracted from the soil initially was
only about 130 pounds per acre; yet more than 300 pounds per
acre were removed in forage from treatment 2 which emphasized
the importance of small K accumulations throughout the soil pro-
file as a source of K for the deep-rooted grasses. Uptake of other
nutrients was proportioned to yield levels which were dependent
on additions of N and K during the experiment. Uptake of nu-
trients from Treatment 2, other than N, was substantially less
than quantities previously applied. However, except for Ca, they
exceeded quantities extracted from the surface soil by ammonium
acetate (pH 4.8). Extractable K and Mg declined to extremely
low levels in soil from Treatment 2 by the end of the 3-year
study. Potassium was obviously deficient, but Mg continued to
be adequate for plant growth based on forage Mg concentrations.
The continued adequacy of P and S over the 3-year experimental
period without applying either nutrient was of interest.

 Summary
 The objective of the liming program used through all phases
 of this study was to maximize white clover growth by main-
 taining surface soil pH at 6.0 and providing an optimum balance
 of Ca and Mg. Because of the continuing increase in organic mat-
 ter which gave higher CEC, and surface liming which delayed
 reaction of lime with the soil, pH 6.0 was not consistently
 achieved until 1968 after addition of 7.0 tons of lime per acre.
 Approximately 60% of the applied P accumulated in the surface
 of these limed soils. Initial total P in the surface soil was in the
 range of 80 to 100 pounds per acre; the average in 1967 was 250
 pounds per acre. Ammonium acetate (pH 4.8) extractable P in
 the virgin soil averaged about 6 pounds per acre and in 1972 it
 was approximately 10 pounds per acre. Only a small fraction
 of total P is extracted by acid ammonium acetate and the per-
 centage extractable is not uniform. Therefore, total soil P cannot
 be estimated accurately from extractable P values. However,
 accumulated P has substantial availability and annual P fertili-
 zation can be reduced on pastures where lime programs have
 been adequate and where consistent fertilization has been prac-
 ticed.