Everg1adXttion MIeo Report r7-13 March 1, 1957
MAKING AND STORING GRASS SILAGE
Dalton S. Harrison
Assistant Agricultural Engineer
Approximately 1300 tons of grass silage have been harvested at the Ever-
glades Experiment Station during the summers of 195, t55 and t'6. This
program was initiated in an attempt to partially solve the problem of winter
feed necessary for supplement when cold weather prohibits the growth of grass.
This report is a summary of the progress.
Machinery & Equipment: For the program of harvesting grass silage a sickle
bar type forage harvester was used. This harvester is auxiliary engine powered.
Two PTO operated conveyor type wagons and boxes(h-ton capacity) were used for
hauling the silage to the horizontal and upright silos. Airplane tires were
mounted on the harvester and wagons. The rear wheels were dualed on the wagons
so as to provide greater flotation when being pulled across the bunker silo. A
Viking H-124S internal gear pump was used to pump undiluted molasses. A star-
wheel type fertilizer hopper was adapted to the harvester to distribute
bisulfite. Total cost of the above equipment amounted to approximately $4_,000.
Although the sickle bar harvester(auxiliary engine operated) was used for
harvesting the 1300 tons of silage, several other type forage harvesters have
been tested and/or observed at this Station. All of them harvested grass
One point worthy of mention is the fact that the "smaller the number of
working parts to a forage harvester, the less maintenance to be expected".
The "shredder" or flail type harvesters show great promise where silage is to
be placed in a silo and "self-fed"; that is, where no unloading of the silo
is contemplated. The length of cut on this type unit cannot be changed and
varies from 1/2 inch to four inches; therefore, unloading the cured silage with
an unloader would be difficult. This type machine and other utility type
rotary harvesters is powered from the PTO shaft through a gear box to the
cylinder shaft, containing the knives, thus a short length of cut is not to be
expected. Reel units, drapers, feed-rolls, cutter bars and blower wheels are
eliminated. In most machines these call for separate drive mechanisms which are
subjected to mechanical failures when operated by inexperienced personnel. In
addition, these "shredder" or "utility" type forage harvesters retail at $600-
$1000, while the standard sickle bar type harvester retails for $1400-40-$000.
The less expensive ones show great promise in harvesting for green feeding, at
a small investment.
Harvesting Costs: Estimated costs of silage operations are recorded in
Table 1. From these data it can be observed that operating costs for harvest-
ing grass silage are $1.76-$1.84 per ton of green chopped material. This
includes labor, fuel for the two tractors and the harvester, and the preser~ i'S
vative--either molasses or Bisulfite. From Table 2, one can observe that r-
spoilage in horizontal silos amounts to approximately 35 percent and thaa'/
"feedable material" can still be produced for a total cost of $2.84-$3, e e
ton. These figures do not include labor involved in removing the silagefom on
the silo or in daily adjustments of self-feeding gates.
\' ^ _
Adding Molasses: Undiluted molasses can be added directly to the chopped
silage by using a one and one half inch internal gear pump driven from the PTO
shaft of the tractor pulling the harvester. A 55-gallon drum mounted on the
rear of this tractor will carry enough molasses for 4-5 tons of silage. A
neoprene hose, from the pump to the discharge chute of the harvester, is fitted
on the end with a 1/4 inch pipe "T" in which two 1/8 inch holes are drilled,
and delivers the molasses directly to the chopped grass as it enters the wagon.
Another pipe "T" with three 3/32 inch holes can be used when the molasses temper-
sture increases during the day, so that approximately 100 pounds of molasses are
delivered per ton of grass,
Adding Sodium Meta-bisulfite: A star whehl type fertilizer hopper mounted
on brackets directly over the feed roll table serves well in delivering bisulfite
salt directly to the grass as it goes into the blower. This hopper, when driven
at approximately 7-10 r.p.m, will deliver 8-10 pounds per ton of grass.
Storing Silage: In an attempt to reduce spoilage which occurs in silos
constructed from either woven wire or airplane landing mat for sides, a horizon-
tal silo made from cresote pressure treated timber was constructed in the summer
of 1956. The silo dimensions are 96 feet long x 15 feet wide x 6 feet high. It
has a capacity of 250 tons of grass silage. Considering 20 percent spoilage,
this silo will hold enough silage to feed 100 cows for a period of 80 days( at
Line posts 4" x 6" x 10' were set on 4-foot centers. Brace posts 4" x 4" x
4' were set behind each line post and braced against a 4" x 4" x 2' "dead-man".
A total of 144 pieces of 1" x 6" x 16' T & G was used for the two sides. Total
costs of material for this silo was $480. Material for construction of two self-
feeding end gates was $89.00, making a total cost of $569.00, excluding labor.
Samples taken for spoilage determination indicate very little change in
percent spoilage as compared to the woven wire side silos, There was a layer
of spoilage 18"-24" on each side and 2"-4" on top. Most of the side spoilage
was a result of the grass not being packed sufficiently tight, '
Properly packed and air excluded from the sides would result in very little
spoilage from the sides of a silo of this type structure.
Table 1. Operating costs for harvesting grass silage
at the Everglades Experiment Station (1955-56) *
$31~ .37 9$..01
3 men at:
No. Tons Harvesting
1955 1956 T955 1956
90 -- 3.3 ---
84 100 4,3 5.0
-- 198 --- 4.5
-- 101 --- 5.0
106 102 3.5 3.0
118 126 4.3 3.8
Av. Cost/Ton 0.21 30 0.20 0 0.99 00.84 00.64 00.72 01.84 01.76
Total Cost 11% 11% 54% 48% 35% 41%
* Fuels and lubricants cost: Gasoline @ $ .25 per gal., Diesel @ $ .15 per gal., and Oil @ 3 .30 per qt.
Sodium metabisulfite @ 0 .10 per pound and Molasses @ .01 per pound.
Table 2, Cost and Percent of Cured Silage Available for Feed excluding
Grass Compaction- Cured Silage: Cost Per Ton:
Variety Ibs./cu.ft. 1955 1956 195 1956
Para 55 60% -- $3.26
St. Augustine 50 72% 70% $2.23 $2.23
Pangola 65 58% 65% $3.98 $3.28
Carib 60 60% 65% $3.0o4 $3.00
Average 57 63% 67% $3.13 $2.84