-4-


 5. Three applications of 200 lb./each of ammonium nitrate to winter annual
 pastures did not increase beef production over that produced from three
 applications of 100 lb./acre each of ammonium nitrate during the grazing
 season.

 Experiment 2. Winter Annual Pastures Overseeded on Frosted Bahiagrass Sod

 The purposes of this experiment were (1) to determine the feasibility of over-
 seeding winter annual pastures on frosted bahiagrass sod and (2) to compare two
 methods of overseeding winter annual pastures on frosted bahiagrass sod in terms
 of animal performance and economic data. The two methods of overseeding were as
 follows:

 1. Treatment I light disking the sod and seeding Wren's abruzzi rye in rows
 7 inches apart with a grain drill at the rate of 67 lb./acre, followed by
 a cultipacker-seeder which seeded 13 lb./acre of Gulf ryegrass and 8 lb./acre
 of Dixie crimson clover over the rye (two 2.5 acre pastures rotationally
 grazed by a group initially containing eight steer calves of British
 breeding).

 2. Treatment II seeding with a pasture renovator (56, 13, and 12 lb./acre
 of Wren's abruzzi rye, Gulf ryegrass, and Dixie crimson clover, respectively)
 without breaking the sod (two 2.5 acre pastures rotationally grazed by a
 group initially containing four steer calves of British breeding).

 The first rotational pasture for each treatment was planted on November 15 and
 the second on November 19, 1973. A complete fertilizer (8-24-24) was applied at
 planting time on all pastures at the rate of 250 lb./acre. Three applications of
 ammonium nitrate at the rate of 100 lb./acre each were made during the grazing
 season. The grazing was initiated on January 16, 1974, and terminated when the
 forage for each treatment was grazed out.

 After an overnight shrink (fast from feed and water), individual animal weights
were taken at the beginning and end of the trial periods. Additional test animals
were added and removed as needed to keep the forage uniformly grazed. In all cases,
individual animal weights were taken after an overnight shrink. Each experimental
group of calves was rotated between the two pasture plots assigned to it as
required for best utilization of good quality forage.

 A mineral mixture (consisting of two parts defluorinated rock phosphate and
one part trace-mineralized salt), plain salt, and clean drinking water were
available to the animals at all times.

 The performance and economic data of growing beef calves grazing winter annual
pastures overseeded on frosted bahiagrass sod are listed in Table 5. The over-all
performance of calves grazing the pastures where light disking of the sod was
followed by seeding with a grain drill and cultipacker-seeder (Treatment I) was
better than that of calves grazing pastures seeded with a pasture renovator without
breaking the sod (Treatment II). Calves on Treatment I had an average daily gain
of 1.70 lb. per head and produced 444 lb. of beef per acre over a period of 132
days; while calves on Treatment II had an average daily gain of 1.52 lb. per head
and produced 242 lb. of beef per acre over a period of 120 days. The much larger
gain per acre by calves on Treatment I compared to Treatment II was also due to a
better stand of forage and better carrying capacity (stocking rate) of these
particular pastures (1.98 versus 1.32 calves/acre).