S3 -6 NOT TO BE TAKEN FROM THIS LIBRARY
Everglades Station Mimeo Report EES 70-5 April, 1970
SOD-SEEDED SORGHUM ON ORGANIC.,:,OILS
R. J. Allen, Jr.
This mimeograph is a preliminary report on sorghums drilled into a Bermuda-.
a-.nn Sorld following winter ryegrass at the Everglades Experiment Station.
Ryegrass has been used for many years either seeded in prepared ground or over-
seeded on well grazed or short grass pastures, and generally has been quite
satisfactory. Sorghums, however, when planted for silage in prepared ground,
have quite often presented the problem of harvesting equipment bogging down in
the soft peat or muck soils during the summer.rainy season. As this does not
occur on established sod, as when harvesting grass silage, the idea of following
ryegrass with sorghum planted into the sod with the Grassland Drill was considered
as a yosnible solution to the problem. In the spring of 1967 an 18 acre pasture
in which Bermuda-grass had taken over from pangola was made available for this
work. It had been planted to ryegrass the previous fall and had been grazed
during the winter and early spring. It was hoped that the Bermuda-grass sod,
even though severely shaded by the sorghum, would hold up the harvesting
equipment in the summer. It was also hoped that shading by the sorghum would
reduce Bermuda-grass competition with the ryegrass seeded in the fall.
The varieties used the first year were: Hegari, an old standard variety
for comparison; Beefbuilder, a forage or silage sorghum hybrid; Robusto, a dual
purpose forage-grain hybrid; Grazer A a sorghum-sudan hybrid; and Brown Top
millet, which was used because seed of the better pearlmillet varieties was not
available. The second year, 1968, the same sorghum varieties were used with
the addition of sorghum-sudan Orbit and forage hybrid Titan R. No millet was
planted. All. of these were obtained locally from Asgrow-Kilgore Seed Co.' In
1969 the varieties used were Beefbuilder, Grazer A, a sorghum-sudan from Binghqm
Seed Co., Grofast, and two sorghum hybrids from Funk Seed Co., 262S and O1F.
Fertilization was as follows: In early 1967 300 pounds ;-r acre of 0-12-16
broadcast; at planting in late May, 100 pounds per acre of 4-8-20 in the drill
rows; and in October, 150 pounds per acre of 4-8-20 in the drill rows for the
ryegrass. In April 1968, 200 pounds per acre of 4-8-20 was applied in the drill
rows for the sorghums, and in the fall, 500 pounds per acre was appL ed broadcast
to the ryegrass. The sorghums were planted in May of -.969 with no further
fertilization. Copper was included in all these applications and Manganese,
.Zinc, and Boron were included in the last one.
It was observed that seedling and early growth was slower in tae sod than-
on bare or prepared ground, which might be expected as the established grass
would compete for the available nitrogen. However, once the sorghum became tall
enough to shade the grass they resumed normal growth rate and matured one to two
weeks later than on prepared ground. The Brown Top millet germinated well but
the seedlings failed completely to survive under these conditions.
Green.weight yields of sorghum varieties Beefbuilder, 2625, and 101F were
estimated to be from 14 to 18 tons per acre on the sod compared to 17 to 25 tons
per acre for the same varieties as estimated from replicated single row variety
trials. The lower yields are considered to be primarily due to grass competition'
and to retarded early growth, and also to possibly lower fertility levels in the
field than in the plots. The important point however, is that the lower yields
were harvested, while in many cases in the glades..area what might have been
higher yielding, crops have had to be abandoned in the field.
In regard to the bogging down problem, this experiment can be considered
very successful. During the harvesting of these sorghum crops for silage no
difficulty due to wet soil conditions was experienced. On two occasions part
of the field was harvested even though surface water was standing in the sod.
The only potential problem during wet weather was created by the concentration
of t-affic at the pasture gate and at the ends of the silage stacks, but by
keeping traffic in these areas to an absolute minimum and handling equipment so
as to avoid formation of ruts, the harvesting operation was not interrupted.
This work is being continued this year in more detail as to row spacing
and seeding rates, fertilization, other planting methods, and grazing of
sorghum-sudan and pearlmillet hybrids.