Florida Agricultural Experiment Stations


lated to be needed to bring the soil moisture of the top 24-inch
strata to field capacity. Soil samples were taken from 0 to 6-
inch, 6 to 12-inch, 12 to 18-inch, and 18 to 24-inch depths in
the irrigated and unirrigated plots at intervals of about one
week. The moisture content of samples from the irrigated plots
was used in determining the time to irrigate and the amount
of water to apply. Supplemental water was applied with a port-
able sprinkler system.

TABLE 2.-PHOSPHOROUS, POTASH, AND BORAX APPLIED PER ACRE EACH
 PASTURE YEAR TO UNIRRIGATED AND IRRIGATED PLOTS.

 Nutrients, Pounds per Acre
 Number of
Year Prior to seeding As top-dressings Top-dressings
 P20O K2O B,O, KO

1954-55*: ...... 136 136 8 150 3
1955-56 ......... 100 100 8 148 2
1956-57 ......... 100 100 8 74 1
1959-60 .......... 108 108 8 162 2

 Seventy-two pounds of nitrogen applied per acre prior to grazing.

 Grazing was begun when the forage was about 10 inches
tall and was continued either until the supply was inadequate
to justify pasturing or until mid-September when the land was
prepared for reseeding. During the first three years the pasture
was grazed when the alfalfa was in the prebud stage. How-
ever, in 1960 alfalfa frequently was in the bud stage, and oc-
casionally there were a few blossoms at grazing time. Except
for this difference, grazing management was uniform between
years and between pastures.
 The pastures were dusted twice with parathion during the
 1956-57 pasture season for control of the spotted alfalfa aphid
 (Therioaphis maculata Buckton).
 Open Jersey, Guernsey, and Holstein heifers were used to
graze the pasture. Each plot was grazed rotationally with sep-
arate groups of heifers by exposing narrow strips of forage to
the animals twice daily (10). The number of animals grazing
each pasture was adjusted in accordance with available supply
and anticipated growth of forage. Shade, drinking water, salt,
steamed bonemeal, and an iron-copper-cobalt mineral mixture
were provided in each pasture. Body weights were taken on
three consecutive days at the beginning, at the end, and at 28-
day intervals during the experiment.