8 BULLETIN 72, HAWAII EXPERIMENT STATION 
plowing to rejuvenate old stands. More of this sort of treatment 
would no doubt be well worth while. 
With a well-distributed rainfall of from 50 to 100 inches per year 
excellent yields can be obtained. In many regions where Napier 
grass can be grown, however, the rainfall is not nearly so heavy nor 
as well distributed. In these drier sections, having an annual rainfall 
of from 20 to 40 inches, irrigation is essential for high yields. A 
furrow system is quite satisfactory, applying water about every 10 
days during the dry weather. Napier grass will withstand extremely 
dry conditions, remaining somewhat dormant and recovering imme- 
diately when enough moisture is supplied, but its growth and yield 
are greatly reduced unless sufficient moisture is available throughout 
the season. This can be understood readily when one realizes that 
Napier grass cut for green fodder contains from 85 to 90 percent of 
water, and that from 75 to 100 tons of such fodder are often cut from 
an acre in a single year. 
UTILIZATION AS A SOILING OR FODDER CROP 
Napier grass grown as a green feed (soiling crop) for dairy cows to 
be fed in the barn or feed lot can be handled in much the same way 
as a crop of corn or sorghum. The first cutting may be made when 
the grass has reached a height of 4 to 5 feet. Under favorable 
growing conditions this first cutting can be made about 60 to 80 
days after planting, depending on the temperature, length of day, 
and available moisture present. It has been observed that a much 
more rapid growth takes place during the warmer months, particu- 
larly when the days are longest. 
The grass may be cut close to the ground level, for the new growth 
comes out from the crown of the plant. The grass should not be 
allowed to mature, for the stalks begin to lignrfy rapidly and the 
digestible nutrients per ton of fodder are lowered markedly. The 
protein content in particular decreases rapidly and the fiber increases 
as the plant approaches maturity. Some dairymen in Hawaii cut 
Napier grass when it stands about 3 feet in height. At this stage it 
is very palatable and has a higher protein content than most grasses 
cut for green fodder. If the grass is cut in a very immature stage 
continuously over a long period the yield may be lowered and the 
root reserves may become so depleted that the stand will be per- 
manently injured. 
The best stage at which to cut and the number of cuttings that 
should be made per year to obtain the maximum yield and palata- 
bility are not definitely known. For dairy cows, however, it is 
important that the grass be cut while it is still very palatable so that 
the stalks as well as the leaves will be eaten without much waste. 
If it is fed with alfalfa or other high-protein roughage, it can be fed 
in a slightly more mature stage than when it is the sole source of 
protein in the roughage. When grown under irrigation in the vicinity 
of Honolulu, 5 or 6 cuttings can be obtained each year and a good 
stand successfully maintained. Such stands should give good ratoons 
for 5 to 6 years or more, particularly if some attention is given to 
fertilization and cultivation during that period. 
When the grass is succulent and soft the whole stalks can be fed 
without much waste. If harvested at a more mature stage, the grass 
