DEPARTMENT OF AGRICULTURE 37

 TABLE 7

 MIXING GUIDE FOR MALEIC HYDRAZIDE


1 Acre 7,500-8,000 7 Pints 25-50 Gallons
/2 Acre 3,000-4,000 3/2 Pints 15-30 Gallons
1/4 Acre 1,500-2,000 1% Pints 5-10 Gallons
100 Plants 100 3-4 Tbsp. /2 Gallons

 IRRIGATION OF FLUE-CURED TOBACCO
 The use of irrigation in the production of flue-cured tobacco
has increased rapidly since 1952. Early tests with irrigation
showed that yields could be increased from 30 to 40 per cent
over non-irrigation and that there was no loss in quality.
In fact, years where irrigation has not given significant in-
creases in yield, the quality has always been significantly in-
creased by as much as 2 to 10 cents per pound. An explan-
ation of this is that rainfall was poorly distributed and
irrigation was used in drought periods which enabled the
tobacco to grow more uniformly. "Stop" and "go" growth is
not unusual for tobacco in Florida during the growing season
because of rainfall distribution. Figure 26 shows expected
monthly rainfall and plant requirements. It should be noted
that these data are based on several years of rainfall records
and that for tobacco to grow satisfactorily there is a need
to supplement the deficiency of rainfall to provide for plant
needs if maximum yields of good quality are to be produced.
Approximately 5 inches of supplemental water is needed over
the expected rainfall. This deficiency and poor distribution
of rainfall has made it very difficult to raise the average
acre yield of tobacco beyond 1,000 to 1,100 pounds without
irrigation. Table 8 shows an average weekly use of water
by the plants. These rates have been found to be very good
in supplying adequate water to produce high yields of good
quality tobacco. In order that plants would not suffer from
a lack of soil moisture between irrigation applications, a
sufficient amount of irrigation water was applied to return
soil moisture to a field capacity after not more than an esti-
mated 70 per cent of the available had been used.
 Recent experiments with irrigation have definitely shown
the effect of rates of water, fertilizer and plant populations
on yields of tobacco.