GENERAL DISCUSSION OF RESULTS
 OVER A 20-YEAR PERIOD
 By Marvin Koger
 A significant feature of this project was that it was a long-
term systems approach which yielded significant information
that had been, and possibly would have continued to be, over-
looked in short-term projects. Examples of unanticipated results
were (a) that clover thrived better under grazing than in plots,
(b) that fertilizer requirements for maintenance of clover pas-
tures under grazing were less than generally recommended, (c)
that clover pastures significantly improved reproductive perfor-
mance of cattle above what was obtained on grass pastures, (d)
that the tendency toward alternate year calving was more pro-
nounced in some breed groups than in others, and (e) that breed
groups ranked significantly different on different pasture pro-
grams.
 Soil changes.-Organic matter content of the virgin soils
prior to establishment of pastures was 2.25% in 1951. In 1957
organic matter had increased to 3.04%7 and in 1964 to 3.82%
with further small increases in some locations through 1972.
This increase in organic matter resulted in higher cation ex-
change capacity and increased water-holding capacity of surface
soils.
 Plant composition.-Since pastures were established on
virgin soils, nearly pure stands of grass and clover were achieved
initially. One-third of the area was planted to bahiagrass and
two-thirds to Pangola digitgrass. The bahiagrass persisted vir-
tually as a pure stand (except in a few low areas subject to
frequent flooding) for a period of approximately 12 years, after
which smutgrass encroached into the bahiagrass sod but at a
slower rate than into other grasses. Pangola established well and
produced heavily for two years, after which time the grass
began to die out in the more heavily fertilized pastures. In 1955
one-half of the Pangoladigitgrass was plowed up and replaced
by Coastal bermudagrass. The remaining Pangola was replaced
by Coastal bermuda in 1957-58 due to inability to maintain or
reestablish Pangola stands. Establishment of Coastal bermuda-
grass varied from good in a few areas to poor in others. Most
stands began to deteriorate within a year, being gradually re-
placed by bahiagrass, native grasses, and weeds. By the end of
phase 3 in 1972, smutgrass appeared to be increasing in density
at an accelerated rate.