African
Journals Online
UNISWA Research
Journal of Agriculture, Science and Technology
VOLUME 4
No. 1 July 2000
Spectrally Selective
Materials For Architectural and Photo-thermal
Applications
A.J. Varkey
ABSTRACT
This paper describes the optical properties of
spectrally selective materials. The concept of spectal
selectivity of solar radiation is discussed with
reference to its application in architecture and
photothermal uses. A brief account of spectrally
selective materials being investigated presently is also
given.
Spectrochemistry of
Solutions: A Vibrational Spectroscopic Study of Ion
Pairing and Upper Stage Transition of Magnesium (II) and
Calcium (II) by Thiocyanates in Liquid Ammonia
Dicky D.K. Chingakule, Peter Gans and J. Bernard
Gill
ABSTRACT
Ion pairing and upper stage transition of magnesium
(II) and calcium (II) with thiocyanate ion has been
studied by Infrared and Raman spectroscopy. A complete
picture of species present in thiocyanate solutions has
been established. The spectral profile consists of five
thiocyanate species namely; a triple-ion, [SCN - M -
NCS]1:1 contact ion pair (M - NCS] solvent-shared ion
pair (NH) M - NH - NCS] “free” thiocyanate ion
(SCN) and an upper stage transition arising from the
excitation of a linear species already in a vibrational
level above the ground state i.e. v2 bending vibration.
This was a feature observed on the lower wavelength.
Counterion Binding Effects
on the Micellar Catalysis of the Base Hydrolysis
of Tris - (1,0-Phenanthroline) Iron (II)
O.O. Soriyan and A.O. Fadiran
ABSTRACT
The effects of counterion binding on micellar
catalysis of the base hydrolysis of FE(phen) has been
investaged. Pseudo first order rate constant, k ,
incrases with increase in the concentrations of ME NCI
and (But) NC1 at any fixed Sodium dodecyl sulphate (SDS)
concentration while the reserve is the case with NH CL.
Low pre-c.m.c. association constants, Km coupled with the
observed low values of the number of monomers per
aggregate, m gave an indication that the micellization of
Sodium dodecyl sulphate is hindered in the presence of
quaternary ammonium salts.
Some Medicinal Plants Used
in Traditional Medicine in Swaziland Oluwole
O.G. Amusan, Pricilla Dlamini, Jerome D. Msonthi, Lydia
P. Makhubu and Bongani B. Dlamini
ABSTRACT
An ethnomedical survey of the Manzini region of
Swaziland was carried out. Traditional medical
practitioners (TMPs) were interviewed in their homesteads
where they practiced traditional medicine. Ethnomedical
uses of plants used were collected from the wild with the
assistance of the TMPs who gave information on them.
Voucher samples of the plants were sent to Pretoria for
scientific identification and the vouchers were deposited
at the national herbarium in Malkerns.
Twenty four of the plants are reported on, giving
details of the preparations for their uses. The uses
include treatments for diarrhoea, dizziness, heartburn,
infertility, sores in the genetals, diabetes,
hypertension, sexually transmitted diseases, for version
of fetus, to increase libido, and as emetic. Some of the
plants are not used for curing or preventing diseases but
their usage is difficult to explain scientifically as
they tend to be magical, causing good luck, warding off
bad spirits, preventing lightning and so on.
The TMPs interviewed were highly knowledgeable in the
area of diagnosis of diseases and taxonomy of plants.
However, many of the plants were not being harvested in a
sustainable manner. There is the need of bringing to the
awareness of the TMPs the usefulness of conservation
measures to their practice for the sustenance of our
biodiversity.
Phytochemical analysis of some of the plants used in
herbal medicine by the TMPs showed the presence of the
following secondary metabolites; alkaloids, antranoids,
cardenolides, flavonoids, glycosides, polyphenols,
saponin, steroids, tannins and terpenoids. These
secondary metabolites are known to have varied biological
activities and may be responsible for the therapeutic
properties of the medicinal plants.
Water Resources Development
in the Mbuluzi River Basin
Jonathan I. Matondo and Thokozani Dlamini
ABSTRACT
The Mbuluzi river basin originates in Swaziland and
exits in Mozambique. The mean annual runoff is estimated
to be 372x10 m. The highest recorded flow is 68m/s while
the lowest flow is 1.1m/s. The current water demand is
estimated to be 8.14m/s while the projected water demand
excluding irrigation water demand is 8.5m/s. From the
above information it means that, the available water
resource is not able to meet the demand especially during
winter months. The required reservoir capacity to meet
the projected water demand (year 2020) has been estimated
to be 212x10 m. The design capacity of the Mnjoli
reservoir which was completed about twenty years ago is
152x10 m. Therefore, the additional required storage to
meet the demand is 60x10m. However, due to over grazing
activities upstream of Mnjoli dam, it is assumed that a
great deal of the live storage has been used up by
sediment accumulation. Therefore, the suggested
additional reservoir storage capacity should be 120x10 m,
assuming that 40% of the reservoir is now full of
sediments.
The Utilisation of
Tractor-Mounted Primary Tillage Implements in the
Malkerns Valley, Swaziland
B.R.T. Vilane and W.O. Mukabwe
ABSTRACT
The study was primarily aimed at determining the
utilization of tractor-mounted primary tillage implements
in Swaziland using 14 case study forms in the Malkerns
Valley. Being descriptive in nature, the study employed
scheduled personal interviews and questionnaires that
were developed, pre-tested and administered by the
authors. The results showed that the 38 primary tillage
implements found on the 14 case study farms were ploughs,
disc harrows and rippers or subsoilers forming 44.7%,
34.2% and 21.1% respectively. The predominant makes of
these implements were Massey Ferguson, John Deere, S.A.
Wonder and Safim, while the others were Case, Leyland,
C.G. Tillage and Agri-Tech. It was evident from the
results that these implements were selected on the basis
of their design, prevailing farm conditions and personal
preferences of the farmers. Operation of the implements
took place on soil types ranging from sand clays to heavy
clays on a total land area of 1461 ha. The operation was
aided by a total of 39 tractors of the makes, Massey
Ferguson, John Deere, Case, Leyland and Ford. Even though
the primary tillage implements were adjusted in the farm
and in the field for depth, cutting width, gang angle and
tilting angle, it was evident from the results that the
majority of the implements were extremely under utilized.
Vegetation Dynamics of
Sloping Lands under Different Grazing Pressures in
the Highlands of Ethiopia
E.J. Mwendera and M.A. Mohamed Saleem
ABSTRACT
The impact of livestock grazing on the dynamics of
vegetation species in the highland slopes of Ethiopian
was studied. This was done by analyzing vegetation
species germinating from cattle dung collected from the
slopes at different times and comparing these species
with those found on the pastures the animals regularly
grazed. It was observed that grazing had little effect on
the species richness of pastures above 3% slope while
moderate and heavy grazing increased bio-diversity of
pastures found on 2-3% slopes. However, heavy grazing
pressure resulted in good grazing ever, heavy grazing
pressure resulted in good grazing quality species being
replaced by poor quality species. The effect of grazing
on vegetation dynamics of the pastures was complicated by
the fact that cow dung was often collected for fuel, and
that at certain times, animals moved to higher slopes
outside the study area. Further research is needed to
determine where the animals go and what type of
vegetation species they graze whenever they leave to
confines of the pastures studied here, and to ascertain
the dormancy and viability of the seeds of the various
vegetation species when they pass through the rumens of
the animals in order to get a clearer picture on the
effects of grazing on vegetation dynamics.
A Mammal Survey of the Lower Usuthu Basin, Swaziland
Ara Monadjem and Themb'alilahlwa A.M. Mahlaba
ABSTRACT
The Lower Usuthu River Basin is set in the lowveld of
Swaziland. The predominant vegetation types are mixed
broadleaf woodland in the western lowveld and Acacia
savanna in the eastern lowveld. The mammalian fauna of
the Lower Usuthu Basin has been poorly documented. The
study set out to survey mammals of the Lower Usuthu Basin
using appropriate sampling techniques.
A total of 45 species of mammals were recorded, or
presumed to occur, in the study area, of which 10 species
are of special conservation status both within Swaziland
and in the southern african region. On Swazi Nation Land,
species diversity and population sizes of mammals,
especially the antelopes, were very low. Large-scale
reduction of habitat may affect the conservation status
of many mammals in the Lower Usuthu Basin.
Seasonal Decomposition of Acute Respiratory Infection Time Series
E.N. Zwane
ABSTRACT
Seasonality in acute respiratory infections is a known
phenomenon but in Swaziland there has been no studies to
prove (highlight) it. The well-accepted X-11 methodology
is used to decompose the monthly time series of
respiratory infections from January 1990 to December
1997. The decomposition not only suggests strong seasonal
effects and but also an increasing trend. Stability
analysis were performed and they showed that the
seasonally adjusted data is stable.
Evolution of Forestry
Policies in Malawi with Reference to the Miombo
Woodlands
Charles B.L. Jumbe, Richard N. Kachule and Charles
S. Mataya
ABSTRACT
This paper traces, through literature review, the
evolution of forestry policies from the pre-colonial
period to the current democratic era in order to assess
(a) forestry policy formulation and implementation and
(b) local community responses to these policies. Present
forestry policies evolved from unrecorded regulations
during the pre-colonial period, whereby traditional
leaders regulated the extraction of forestry resources.
Specifically, traditional leaders preserved certain
forest species with medicinal values and prohibited
cutting down of trees in reserved forest patches
considered as sacred places. In the colonial period, the
forestry sector was guided by agricultural sector
policies, which also extended to include forestry.
However, within specific areas of forestry,
“Forestry Ordinances” were used as a tool to
guide the management, protection, control and utilization
of forestry resources. These Ordinances were regularly
reviewed to respond to new and changing demands of the
forestry sector. The coherent forestry policy was,
however, developed after Malawi attained its independence
in 1964. In general, policies pursued between the
colonial periods and prior to the Structural Adjustment
Programme prohibited local community participation in
forestry matters. However, during the current democracy
era, the present policy advocates community participation
in forestry matters, a concept that was introduced by the
colonial government in the 1926s. This suggests that
policies that governed the forestry sector in the
colonial period have, to a certain extent, shaped the
current status of the forestry sector.
Soil Populations of
Fusarium Species at Lobamba Lomdzala, Mahlanya
During the 1998/99 Cropping Season
A.B. Mansuetus, I.S. Kunene and E.N. Dlamini
ABSTRACT
Fusarium species whose members have telomorphs
in the Gibberella fujikuroi species complex are
one of the major groups of pathogens that cause diseases
of maize. Mating population A (pink Fusarium m
moniliforme) and mating population f (yellow fusarium
moniliforme) which had shared the Fusarium
Moniliforme and Fusarium thapsinum
respectively. These two species are mainly found in
cultivated fields where maize and sorghum are grown.
Soil samples were randomly sampled at three different
sampling times from Mahlanya. The serial dilution method
was used to isolate (Fusarium species and the
isolates were then subcultured on Nash and Snyder Agar.
The results from this study show that large populations
of Fusarium species occur in the soil at Mahlanya.
These populations were lowest before planting but
increased with advancement in the growth stage of maize
crop. Pink Fusarium moniliforme occurred in
significantly greater numbers than Fusarium thapsinum
in all the sampling times chosen.
Production and Marketing of
Smallholder Tobacco: Effect on Household Food
Security, Nutritional Status and Intra-household Labour
Allocation in Malawi
Hardwick Tchale and Abdi K. Edriss
ABSTRACT
The underlying analysis in this paper is based on the
data that were collected through the International Food
Policy Research Institute (IFPRI) University of Malawi,
Bunda College Rural Financial Market Study. The study was
conducted during the 1994/95 and 1995/96 agricultural
seasons. The objective was to assess the impact of access
to agricultural credit on food security among smallholder
farmers in Malawi. The analytical framework was based on
estimating a recursive model to assess the effect of
tobacco production and marketing on household welfare
variables such as income, expenditure patterns, household
food security and labour allocation.The results indicate
that while the growing and marketing of tobacco has a
positive and significant effect on household income,
except for investments in dwelling units and agricultural
equipment, there are no significant differences in
household welfare variables between tobacco growers and
non-growers. Smallholder farmers are unlikely to benefit
from tobacco. Amongst smallholder farmers, tobacco income
is only earned during the selling season and due to lack
of savings, this income is unable to support the
households evenly throughout the year. The level of
income earned depends on the market channel that is used.
This study has established that the auction market is the
most viable. However, due to access problems and the
urgent need for cash, most smallholder farmers end up
selling their entire crop to estates or intermediate
buyers at lower prices. Thus there is need to promote
collective action among smallholder farmers to ensure
that they sell most of their crop at the action floors.
This will not only improve the prices they get but will
also make savings mobilization easier.
Knowledge and Perceptions
of Extension Officers on Striga spp. in Lilongwe
and Machinga Agricultural Development Divisions in Malawi
H.R. Mloza-Banda, V.H. Kabambe, M. Mphepo and O.
Chivinge
ABSTRACT
A training session on Striga spp. biology, ecology and
control practices was held for extension officers from
sixty extension planning areas (EPAs) of Lilongwe and
Machinga Agricultural Development Divisions in Malawi.
Following the training session a questionnaire was then
used to assess whether extension officers meet the
requirements for explaining to farmers the complexity of
the Striga spp. problem. Although the officers appeared
conversant with potential oposition for control of Striga
spp., their knowledge about the biology and ecology of
the parasitic weed was weak.
Front-line agricultural extension staff must be aware
of the biology and ecology of Striga spp., and the
long-term approach to be followed to manage Striga spp.
effectively. In turn this knowledge must be made
available to farmers through participatory approaches
that are `farmer' or `situation' specific. The
development of appropriate extension materials and
practical training will be required if extension staff
are to communicate potential innovations to combat Striga
spp.
Presence and Effects of
Chemical Toxin on Feeding of Cowpea Aphid, Aphis
craccivora Koch (Homoptera: Aphididae) on Six Highly Resistant
Varieties of Cowpea Vigna unguiculata (L) Walp,
(Leguminosae
A.K. Ansari, h.F. van Emden and S.R. Signh
ABSTRACT
Cowpea, Vigna unguiculata (L.) Walp is one of
the most important grain legumes produced in Nigeria. It
is mostly grown as a mixed crop with cereals in a
traditional cereal/legume farming system. Cowpea aphid, Aphis
craccivora Koch is the main aphid pest of cowpea. In
view of the importance and serious damage caused by
aphids, a total of 613 varieties of cowpeas were screened
for resistance in International Institute of Tropical
Agriculture (IITA), Ibadan, Nigeria. During the screening
it was found that aphids died faster without reproducing
and their longevity was very short on six varieties (Tvu
408 - P2, 801, 310, 266 - P1 2845 and 337-3F0 with high
antibiotic properties. These varieties along with one
susceptible variety (Tvu.76(Prima) were used for
conducting two experiments together to find out the
presence of a chemical and their role in aphid's feeding
and survival. Comparative studies of the number of honey
dew drops produced on varieties used in the experiment,
and the reaction of the aphids in terms of probing time,
longevity and number of nymphs produced on prima painted
with the juice of the above mentioned highly resistant
varieties, suggested that the resistance factor exists in
the form of a toxin or a feeding deterrent.
Effect of Cropping
Practices on Weed Species Composition in a Groundnut
(Arachis hypogaea, L.) Crop in Central Malawi
H.R. Mloza-Banda
ABSTRACT
The effect of rotation and weeding practices on weed
species composition were evaluated in a groundnut (Arachis
hypogaea, L.) crop in a three-year field experiment
in Central Malawi under ridge-tillage practices. Weeding
practices consisted of weeding twice including
earthing-up, weeding once, and no weeding, respectively,
for the duration of the groundnut crop. The number of
individual weed species was determined and used to plot
weed frequency graphs and derive weed diversity index.
It was shown that although the groundnut crop had more
than a dozen week species, the most dominant species were
Commelina benghalensis, Rhynchelytrum repens, Eleucine
Indica, Bidens pilosa, Acanthospermum hispidus.
Although the effect of the hoe-weeding regimes on the
subsequent weed flore were subtle, it is evident that
inter-row cultivation had the effect of reducing the
prevalence of certain weed species early in the season
while enhancing diversity and density above ground
through recruitment from the seedbank. Sunflower, as the
preceding crop in rotation, was an effective crop in
reducing size of the subsequent weed flora in rotational
cropping.
Solvent Effects on the
Micelle - Influenced Aquation Reactions of Some Iron
(II) Phenanthroline Complexes in Various Solvent Systems
A.O. Fadiran, J. Ige, and O.O. Soriyan
ABSTRACT
The relative rates of the micelle-catalyzed/inhibited
aquation reactions of the complexes: Fe(Ph2Phen),
Fe(Me2Phen) and Fe(MePhen were investigated in ethylene
glycol, water and aqueous acetone. The pseudo first oder
rate constant, K vs (Triton X-100) profiles reveal that
at all the (TX-100) concentration ranges considered for
ethylene glycol and water, and for aqueous aceton at
(Triton X-100) >/minus 15.00(%v/v) the pseudo first
order rate constant, k values follow the order: Fe(Me4
Phen)> Fe(ph2Phen) , suggesting a substrate binding
strength of the order: Fe(Me2Phen) rates of the complexes
in ethylene glycol and water fall within the same range
of 0.0 - 100.0 x 10 S while the aquation rates in aqueous
acetone are generally about 10 cubic faster. These
observations have been attributed to evolution of
different micellar types and aquation mechanisms.
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