A Cover Crop Program for Florida Pecan Orchards 11

 At the beginning and again in 1933 soil samples were taken
for three depths at definite locations in each plot where no sul-
fate of ammonia was applied. From the same places volume
samples averaging about 10 pounds each were taken in 1934.

 PRECIPITATION
 The rainfall at Monticello as recorded by the U. S. Weather
Bureau for 1927 to 1934 is shown in Table 1. These data are
presented as information only, as no attempt was made to de-
termine the effect of precipitation on growth and yield of pecans.
The rain gage of the U. S. Weather Bureau was located about
200 yards from the orchard in which the experiment was con-
ducted until August 1, 1930, when it was moved to another farm
about one mile to the southwest.

 CROP CONDITIONS IN EXPERIMENTAL ORCHARD
 The trees selected for the test were low in vigor when the
work was started in 1927. The 1928 production was preceded
by several years of no yields or at least light ones, and was
immediately followed by one failure and two light crops (Table
4). Similar yields are quite common with bearing trees low
in vitality and making poor growth.
 It should be pointed out that yields throughout the experiment
would have been much higher if insects had not taken heavy
tolls, as both leaf and nut case-bearers caused severe damage.
It was interesting to observe in the spring of 1931 that the
Frotscher trees where legumes were grown during both winter
and summer had stored a sufficient food reserve in the twigs
to force a heavy pistillate bloom after the original terminal
buds had been destroyed by the leaf case-bearer. However, the
staminate bloom, forced at the normal time, was extremely light
due to damages caused by this insect; therefore there was a
shortage of pollen during the critical period of pollination which
resulted in a light Frotscher yield in 1931.
 As a result of the 1931 drouth and the subsequent warm
winter and consequent delayed dormancy of the trees, together
with the severe freeze in March of 1932, again there was a very
light crop produced by the Stuart. The trees were extremely
late and irregular in forcing growth and had a very light bloom
in 1932, and were not in full leaf until well into June, all of
which contributed materially to the very low production for that
year. The Frotscher trees, however, were not so severely upset