Florida Agricultural Experiment Station


 Returns per acre of the Frotscher above materials cost were
 relatively low during each of the first four years. However, for
 1932 to 1934 they were $122.40 and $126.65 with Austrian peas
 and hairy vetch, respectively, which received sulfate of ammonia,
 and $76.84 and $72.59 with the same crops, respectively, where
 no sulfate of ammonia was applied. The data in Table 7 show
 that returns were lower where oats were grown than with no
 planted cover crop, except in one section. Therefore, even with
 the low prices received for the nuts during 1932 to 1934 the
 returns above cost of materials in the legume plots were quite
 significant and showed a favorable increase. For the duration
 of the experiment the returns were highest where sulfate of
 ammonia was applied and legumes were grown in both winter
 and summer. Likewise, without cover crops and in the plot
 where oats and C. spectabilis were grown, returns were slightly
 higher where sulfate of ammonia was applied.
 Stuart produced fewer nuts than Frotscher and therefore gave
much lower returns; consequently each pound of nuts carried
a higher cost for materials which was lower in the legume than
in the other plots for 1932 to 1934. Returns above cost for
materials figured on an acre basis of 17 trees, however, showed
that during the second period they were $28.56 and $26.01 where
no sulfate of ammonia was applied in the legume Plots 1 and 2,
respectively, but where sulfate of ammonia was applied they
were $40.12 and $33.49. The returns were slightly higher also
in the same two plots where sulfate of ammonia applications
were made for the duration of the experiment. With complete
fertilizer applications during 1932 to 1934 with sulfate of am-
monia, trees in the unplanted plot gave a greater return than
in the section where only phosphorus and potash were applied.
It will be seen in Table 7 that even with the light yields and
low nut prices which prevailed the returns of the Stuart above
cost of materials were much better with legumes than they were
in the unplanted and winter non-legume Plots 3 and 4.

 EFFECTS OF COVER CROPS ON THE SOIL
 TUBE SAMPLES
 In 1928 and again in 1933 soil samples were taken at three
depths from definite locations between the trees in sections A
of each plot to which no sulfate of ammonia was applied. The
soil from each plot for the given depths of 0-9 inches, 9-21 inches,
and 21-33 inches was mixed into a composite sample, passed
through a two millimeter sieve, and the percent organic matter