Improvement of natural pastures (rweya land) by oversowing with leguminous plant species in Bukoba district, Tanzania
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Date
2014
Authors
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Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
A study was conducted in three rweya sites at Maruku Agricultural Research and
Development Institute, Bukoba. Five leguminous plant species (Centrosema
pubescens, Desmodium intortum, Macroptilium atropurpureum, Clitoria ternatea
and Puereria phaseoloides) were oversown into natural pastures to assess their
influence on forage dry matter yield, nutritive value and soil fertility. Sites were
selected based on differences in soil fertility. These were; one with high soil fertility,
two with medium soil fertility and three with poor soil fertility. Two soil samples
were taken at each site for analysis, one before oversowing and another eight months
after oversowing. Forage samples were also harvested twice, at seven months after
oversowing and seven weeks after first harvest. Soil analysis indicated that
oversowing improved soil nitrogen and available phosphorus but had no impact on
soil organic matter and pH. Macroptilium atropurpureum and C. ternatea
disappeared from site three while C. pubescens and P. phaseoloides performed well
across all sites. In the first harvest the DM yield in all sites ranged between
778.48±162 and 1384.36±162kgDM/ha and its was not significantly different
between treatments. In the second harvest, DM yield ranged between 1013.63±184
and 2564.6 l±188kgDM/ha. This harvest had generally higher DM yields than the
first. Generally, the control treatments had lower DM yields than the oversown
treatments. The CP content in the first harvest ranged between 4.62±0.29 and
11.28±0.64%. Highest value was observed in C. pubescens oversown treatment
while the lowest value was observed in the control treatments. In the second harvest,
the CP content ranged between 5.44±0.43 and 9.14±0.64%. It was also abseryed.that
all oversown treatments had CP values above 6.5%. NDF content in the first harvestiii
ranged between 69.03±1.72 and 74.36±1.26% for oversown treatments and the
control treatments it ranged between 74.89±1.72 and 79.68±1.26% in all sites. In the
second harvest, NDF content for oversown treatments ranged between 69.6±1.72 and
76.77±1.26% and for the control treatments it ranged between 75.16±1.72 and
78.04±1.26%. The ADF content in the first harvest ranged between 37.22±0.89 and
46.62±0.61 for oversown treatments and the control treatments ranged between
44.57±1.35 and 47.67±0.89%. In the second harvest, ADF values ranged between
40.78±1.35 to 48.85±0.89% and 48.27±1.35 to 50±0.61% for oversown and control
treatments respectively. In vitro dry matter digestibility in the first harvest ranged
between 34.44 to 41.59±3.11% and 28.54±2.13 to 37.27±1.81 for oversown and the
control treatments respectively. In the second harvest it ranged between 30±3.11 and
38.74±1.81% and 27.78±2.13 to 32.52±1.81% for the oversown and the control
treatments respectively. The In vitro organic matter digestibility ranged between
49.93±2.49 to 55.98±3.14% and 42.45±2.49 to 47.46±1.66% for the oversown and
control treatments respectively. In the second harvest it ranged between 47.17±2.49
to 52.49±1.66% for the oversown treatments and 41.71±2.49 to 46.12±1 .66% for the
control treatments. In all harvests the control treatments had lower values than the
oversown treatments. It was concluded that, oversowing leguminous plant species
into natural pastures improved soil chemical properties and also it increased the
nutritive value of natural pastures in terms of higher digestibility values, CP contents
and reduced cell wall contents (NDF and ADF). It was also observed that,
oversowing had no effect on ash and ADL content of natural pastures.
Description
Dissertation
Keywords
Improvement, natural pastures, (rweya land), leguminous, plant species, in Bukoba district, Tanzania