EFFECT OF PHOSPHORUS LEVEL AND DEFOLIATION DATE ON SEED PRODUCTION OF STYLO (STYLOSANTHES GUIANENSIS CV. SCHOFIELD) IN THE SOUTHERN GUINEA SAVANNA ZONE OF NIGERIA
EFFECT OF PHOSPHORUS LEVEL AND DEFOLIATION DATE ON SEED PRODUCTION OF STYLO (STYLOSANTHES GUIANENSIS CV. SCHOFIELD) IN THE SOUTHERN GUINEA SAVANNA ZONE OF NIGERIA
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Date
1982-03
Authors
EZEAKU, GODFREY U.
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Abstract
During 1979-1981, three experiments were conducted to
i n v e s t i g a t e the effect of phosphorus and d e f o l i a t i o n on the
growth, seed production and percentage seed germination of
S. guianensis cv. Schofield, using a s p l i t plot design.
1. Experiment I considered the effect of five phosphorus
levels (0, 30, 60, 90 and 120 kg P/ha) on seedling emergence,
dry matter (DM) yield, herbage chemical composition and seed
yield of S. guianensis. Counting and cutting dates constituted
the sub-plots for seedling emergence and DM yield while
seed harvesting date formed the sub-plot for chemical composition
and seed yield.
2. In experiment II the effect of five defoliation
treatments (no defoliation compared with defoliation on
25/7, 25/8, 25/9 and 25/10/79 = Main plot) on seed yield of
S. guianensis regrowth was sought. The sub-plot treatment
was different seed harvesting dates.
3. Experiment III examined the effect of five level of
phosphorus on percent germination of S. guianensis seed
harvested on different dates from 3/l/81 to 14/3/81.
The number of seedlings emerging increased progressively
with increasing level of P. By the 14th day of sowing,
approximately 75 percent of the t o t a l seedlings counted on
day 21 had emerged. DM yield increased from I3.5t/ha without
P to 15t/ha with 120kg P/ha in the year of establishment. The
corresponding DM yield values two years after (1981) in response
to residual P were 14t and 19.2t/ha respectively.
Percentage crude protein in tops rose with additional P and
declined with delay in harvesting as hay. Crude fibre, ether
extract, ash and nitrogen free extract percentage were not
consistent in respect of either P or date of cutting.
Seed yield in the first year (1979/80) maximised at 60 kg
p/ha and tended to decline at higher P doses. In 1980/81 however,
seed yield response to residual P reflected the level of P applied
in the 1979 growing season. Late January/mid February appeared
the most suitable for harvesting S. guianensis cv. Schofield for
seed. On this basis, and using modest P (30 to 60 kg P/ha),
standing seed yield varied from 325 to 434 kg/ha for the 1979/80
crop. The corresponding total seed yield values were 387 to 507
kg/ha and 346 to 445 kg/ha, respectively. Seed yield declined
considerably after mid-Ibbruary due to severe pod shedding
(standing seed) and intensified seed gathering by harvester ants
(fallen seed).
Defoliation between late July and late September resulted in
the highest seed yield when seed harvesting occurred in mid-
February. The data suggested that S. guianensis cv. Schofield
regrowth could be for conservation up to late September without
necessarily causing any observable reduction in subsequent
total seed yield.
P had no effect on seed germination. The number of fallen
seed germinating significantly exceeded that of standing seed.
Description
A Thesis submitted to Ahmadu Bello University in partial
fulfillment of the requirements for the degree of :
MASTER OF SCIENCE
Department of Animal Science
Faculty of Agriculture
Ahmadu Bello University
Zaria - Nigeria
March, 1982
Keywords
PHOSPHORUS,, DEFOLIATION,, STYLOSANTHES,, GUIANENSIS,, SCHOFIELD,, SOUTHERN GUINEA SAVANNA,, ZONE OF NIGERIA