AGRONOMIC STUDIES
 Methods

 By G. B. Killinger

 The third phase of agronomic research involved three pasture
programs over the 7-year period October 1965 through Septem-
ber 1972. The program and pasture layout is shown diagramati-
cally in Figure 1, and details on the treatments used in each
program are shown in Table 1. Program 1 was a standard pas-
ture based on results of Phases 1 and 2. Program 2 was designed
to evaluate the benefits of renovating old clover-grass pastures
which had become infested with smutgrass (Sporobolus poiretii)
and which had declined in productivity. Starting in the fall of
1964, one-fourth of the Program 2 acreage in each replication
was renovated each year, so all renovation was completed by the
fall of 1967. Renovation consisted of plowing and seeding to
small grains, ryegrass, and clover. The Pensacola bahiagrass,
not completely killed by the plowing, reestablished itself during
the following spring and summer. In Program 3 one-half of the
clover-grass pastures were under seepage irrigation coupled with
an increase in fertilizer for the irrigated portions.
 Annual forage production was estimated for each pasture by
harvesting samples from caged plots. Twenty, thirty-two, and
sixteen cages were sampled in Programs 1, 2, and 3, respectively,
at approximately 30-day intervals during the growing season.
Harvested forage was usually in an active growth stage. A sam-
ple consisted of a 10-foot strip 3.3 feet wide from each caged
area. At each harvest the cages were moved to a new freshly

 Table 1.-Description of Pasture Programs.
 Annual Fertilization*
 Program Forage Total 0-10-20
 Number Plants Acres (Ibs./A)
 1 Clover-grass 65.47 300
 2 Clover-grass 70.30 300**
 (renovated)
 3 Clover-grass 18.57 300
 Irrigated Clover-grass 16.08 500
 SIn the fall of 1967 all of the 0-10-20 applied contained 200 pounds of
 Fritted Trace Elements 503 per ton of fertilizer. Dolomite limestone was
 applied at a rate of 1 ton per acre to pasture 21 E, F, and G, 22 A, D, E,
 and F, and to 32 A.
 In the year of renovation of Program 2 pastures the winter crop received
 500 Ibs./A of 8-8-8 fertilizer at seeding and was top dressed with 200
 Ib/A of ammonium nitrate.