Seed production, dry matter yield and nutritive value of two stylosanthes species as affected by fertilizer application and time of harvest at Morogoro.
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Date
1997
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
A study comprising two field experiments was conducted to
examine the effects of nitrogen
fertilizer
application
time
and
and phosphorus
(N)
harvest
of
(P)
seed
on
production, dry matter (DM) yield and nutritive value of
hamata
Stylosanthes
Stylosanthes
and
guianensis
at
Morogoro. Split-plot experimental design was used in the
study.
In experiment I, two levels of N (0 and 30 kg/ha) and
two levels of P (0 and 3 0 kg/ha) were arranged factorially
as a main-plot treatment. In experiment II, four levels of
P (0, 30, 60, and 90 kg/ha) were applied with 30 kg N/ha as
a main-plot treatment. In both experiments sub-plots were
harvested at 50 % flowering stage, 4th , 5th , 6th and 7th week
post 50 % flowering stage.
The results showed that N application increased seed
yield, DM yield and crude protein
67.3, 45.68 and
(CP)
% of S.hamata by
9.63 percent as compared to the control,
respectively. N application also increased CP %, in vitro
dry matter digestibility (IVDMD) %, in vitro organic matter
digestibility
content
of
(IVOMD)
%
S.guianensis
andmetabolizable
by4.44,
5.92,
energy
3.64
and
(ME)
3.59
percent over the control, respectively. However, the DM and
seed
yield
of
S.guianensis
tended
to
decline
with
N
application. Phosphorus fertilizer application on the other hand did not affect seed yield and DM yield of S.hamata.
However, it increased the leaf:stem ratio, harvesting index
and seed yield of S.guianensis.
herbage
produced
declined
in
The over all quality of
both
species
with
P
application in terms of digestibility and subsequently the
ME content as compared to the control. Maximum return per
Tanzanian Shilling (Tsh)
invested on N was obtained from
S.hamata kept for both seed and fodder production (12.02
Tsh) , followed by the same species kept for seed production
alone (9.75 Tsh) . The maximum return per Tsh invested on P
was obtained from S. guianensis kept for seed production
alone
(8.02 Tsh),
followed by the same species kept for
both seed and fodder production( 5.05 Tsh).
In both S.hamata and S.guianensis increasing time of
harvest increased harvesting index, seed yield and herbage
DM yield. However,
peak seed yield was not yet attained
within the range of harvesting time considered for S.hamata
while it was at the
6 th week for S.guianensis.
In both
Stylosanthes species ash %, CP %, and DCP content declined
with
increasing
time
of
harvest.
However,
the
acid
detergent fibre (ADF) %, and acid detergent lignin (ADF) %
in DM of the two species responded to increasing time of
harvest differently. Both ADF and ADL % in DM increased in
S.hamata and declined in S.guianensis with increasing age
of the plant.
This trend was reflected on the in vitro
digestibility value of the feed which declined continuously in
S. hama ta
and
increased
after
the
5ch
week
in
S.guianensis.
It was concluded that starter dose of N application
enhanced seed production,
DM yield
and quality of
the
forage in S .hamata; where as S.guianensis benefited only in
terms of quality improvement of the forage. Application of
P was not beneficial under Morogoro condition for S.hamata
while for S.guianensis, P application at the rate of 60 kg
P/ha gave higher seed yield and quality forage than the
rest of P levels tested.
Large yield differences were observed between early
Vs. late harvesting time in both S. hamata and S. guianensis
in terms of seed yield, DM yield and quality of herbage
produced. This preliminary work, therefore, suggested that
harvesting time for optimum seed production should be at
the 7th and 6 th week post 50
Description
A dissertation submitted in partial fulfillment of the requirements for the degree of master of science in agriculture
Keywords
Seed production, Dry matter yield, Fertilizer application, Nutritive value, Stylosanthes species, Morogoro.