Florida Agricultural Experiment Station


 Neither non-legumes in winter with a legume in summer nor
the absence of planted cover crops gave satisfactory results in
trunk growth. However, there was some increase during the
second period over the first in both of these areas where sulfate
of ammonia was applied except that there was no difference in
the Stuart growth where no cover crop was planted.
 It will be noted (Table 3) that Crotalaria spectabilis in sum-
mer with either Austrian peas or hairy vetch in winter produced
the greatest increase in tree growth. Differences in growth
response of the two varieties were only slight, however, and
Stuart trees showed up better in growth than they did in yields
(Fig. 9).
 It will be noted in Table 3 also that growth increment after
1931 was greatest in each instance where sulfate of ammonia
was applied. The most wood growth during the period of the
experiment, however, was made by trees where the cover crops
consisted of legumes during both winter and summer and the
nitrogenous fertilizers were applied annually. (Figs. 10, 11,
12, 13, 14.)
 Yields: The yield records as presented in Table 4 were grouped
into periods including the same years as given for growth. The
trend of tree yields followed rather closely growth response




















 Fig. 10.-Stuart trees in unplanted Plot 3-A where no sulfate of am-
monia was applied. Note Crotalaria spectabilis in Plot 4, right background.
Note poor condition of trees and lack of foliage; compare with Plot 2 as
shown in Fig. 9.