3-inch grass, but warming was retarded and maximum tempera-
tures were not as high in the taller grass (30). Observations on
muck soil at the Everglades Experiment Station during the
1963-64 winter showed that temperature readings at 12 inch
above the soil surface were similar in tall and short pangolagrass
and that there was no appreciable time lag in temperature
changes under the tall grass. It seems probable that effect of
forage accumulation on crown temperature and survival is in-
fluenced by soil type, soil moisture, and severity of cold. Fall
production of 1 to 2 tons of dry matter per acre for midwinter
grazing is not likely to affect winter survival in central and south
Florida, although heavily matted growth increases the hazard
of winterkilling. Removal of forage by grazing or hay harvest
not later than January 1 is suggested.

Growth Regulators
 The relationship of dormancy to damage reduction led to
experiments with chemical treatment to prevent growth during
the winter. Plots in the Gainesville area fertilized with N in the
fall were sprayed with maleic hydrazide after the forage was
removed (29). It was found that pangolagrass treated with the
growth retardant remained dormant during alternating periods
of warm weather and frost, and that as a result more of the
pangolagrass was alive in the spring. No measurable advantage
was found during prolonged or uninterrupted cold winters.
Maleic hydrazide applied at the rate of 4 pounds per acre in
November at the Range Cattle Station retarded pangolagrass
growth until March, but a 2-pound rate had no effect on growth
renewal. No appreciable winterkilling occurred on either treated
or untreated areas. The per-acre cost of this material is high,
and it is not recommended for preventing winter damage on
pangolagrass.

Cultivation and Age of Sod
 Seven pangolagrass pastures at the Range Cattle Station
were renovated in June 1963 by cutting with a heavy-duty roto-
tiller followed by levelling disk and packer. The grass in these
fields made vigorous growth after renovation and fertilization
and was grazed in October and November of 1963. When frosted
in mid-November they had 2 to 3 tons per acre more mature
herbage than adjoining areas similarly fertilized and managed
but not renovated. Survival in March 1964 was 90% or higher
on the renovated pastures, and less than 1 % on the undisturbed
sod (Figure 8).