91 research outputs found
Sediment and nutrient loads into river Lwiro, in the Lake Kivu basin, Democratic Republic of Congo
This study assessed sediment and nutrient loads in Lwiro river, Lake Kivu basin in the Democratic Republic of Congo. Water discharge was measured and water samples were collected twice a month from 6 sites in Lwiro river system and analyzed for total suspended sediment (SS), temperature, pH, dissolved oxygen (DO), chemical oxygen demand (COD), five-day biological oxygen demand (BOD5), alkalinity and nutrients (P, N, PO43-, NO3- and NH4+) using standard methods. Results show that the concentration of BOD5 was low (1.08 ± 0.83 mg/L); but COD (13.13 ± 6.26 mg/L) and SS (1.15 ± 0.36 mg/L) were high in the industrial effluent than in agricultural effluent (2.7 ± 0.77 mg/L for BOD5; 9.05 ± 3.55 mg/L for COD and 0.81 ± 0.36 mg/L for TSS). It was observed that all these values were low compared to the standard limit proposed by UNECE and Uganda standard. TSS, nutrient and other chemicals parameters load analyzed were high in agriculture effluent than in industrial effluent except for NH4+ load. Temporal variation and site difference between TSS and nutrient load were significantly different (F=5.54, p< 0.005 for SS; F= 8.59, p< 0.005 for TP and F=7.63, p< 0.005 for TN). Techniques for reducing nutrient and TSS loads should be initiated in the microcatchment to protect the Lake Kivu.Keywords: Sediment; nutrient load; industrial; agriculture effluent; Lwiro river; Lake Kivu
Revisiting application of statistics in Agricultural Research in sub-Saharan Africa: Entry points for improvement
The importance of statistics in empowering the agricultural research
process and sharpening interventions cannot be over-emphasized.
Undocumented evidence points to misconceptions, misuse or underuse of
statistics among agricultural researchers in sub-Saharan Africa (SSA);
pointing to the possibility that the subject has been part of the
causes the unfulfilled targets in the agricultural sector in the
region. The objective of this study was to analyse and document
weaknesses in statistical practice in agricultural research, with a
view to identifying entry points for strengthening the performance of
the sector for SSA to be able to achieve its set goals. A desk study
involving 165 research articles published in the African Crop Science
Journal over the period of 17 years (2000 to 2017) was conducted
through a rigorous SWOT analysis for issues related to the use of
statistics in the implementation of agricultural research in SSA. A
checklist consisting of key elements related to study design; data
collection, analysis and exploitation; and presentation, was used to
guide the interrogation. Findings indicated that researchers generally
made explicit description of treatment structures that fairly matched
the study objectives and hypotheses (in the few cases where they were
stated), with a few weaknesses in the description of factorial
treatment structure. The Randomised Complete Block Design was most
commonly used among the designs, with 3-4 replicates. However, there
was hardly any justification for its use, as the blocking factors were
never mentioned and thus their role in determining the precision of the
results was difficult to determine. Analysis of Variance was the main
method for data analysis, followed by correlations. The F-test and the
associated P-values were the basis for decisions on treatment
differences. Most researchers had problems with presentation and
interpretation of P-values and significance level. Post adhoc tests
mostly used the Least Significant Difference (LSD) for pairwise mean
comparisons, with little consideration for the treatment structure, the
number of treatments and the nature (qualitative or quantitative).
Generally, estimates of treatment means were presented together with
various measures of precision, in both tables and graphical forms. In
several cases, LSD was used or misused interchangeably with standard
error (SE) or standard error of difference (SED). Several statistical
software were used for data analysis and presentation, with the main
ones being SAS, Genstat and MSTAT-C. Key entry points for improvement
heavily lie in human and infrastructural resource capacity improvement,
most specifically in (i) periodic review of university and other
tertiary institutions\u2019 curricula to provide sufficient time
allocation, physical space and relevant infrastructure for true hands
on practice; (ii) more effective utilisation of the few statisticians
available in the region, (iii) short term staff in-service retooling
courses, (iv) sustained statistical service units wherever necessary,
and (v) provision for periodic interactive statistician-researcher
platforms (such as conferences and workshops) for sharing notes on
challenges and achievements during implementation of their research
programmes.L\u2019importance des statistiques pour renforcer le processus de
recherche agricole et affiner les interventions ne saurait \ueatre
trop soulign\ue9e. Des preuves non document\ue9es font ressortir
des id\ue9es fausses, un usage abusif ou un usage insuffisant des
statistiques parmi les chercheurs en agriculture en Afrique
subsaharienne (ASS); soulignant la possibilit\ue9 que le sujet ait
fait partie des causes des objectifs non atteints dans le secteur
agricole de la r\ue9gion. L\u2019objectif de cette \ue9tude
\ue9tait d\u2019analyser et de documenter les faiblesses de la
pratique d\u2018 utilization de la statistique en mati\ue8re de
recherche agricole, en vue d\u2019identifier les points
d\u2019entr\ue9e permettant de renforcer les performances du secteur
afin que l\u2019ASS puisse atteindre ses objectifs fix\ue9s. Une
\ue9tude th\ue9orique comprenant 165 articles de recherche
publi\ue9s dans le journal African Crop Science Journal dans une
p\ue9riode de 17 ans (2000 \ue0 2017) qui ont \ue9t\ue9
r\ue9alis\ue9es au moyen d\u2019une analyse SWOT rigoureuse des
probl\ue8mes li\ue9s \ue0 l\u2019utilisation des statistiques
dans la mise en \u153uvre de la recherche agricole en ASS. Une liste
de contr\uf4le comprenant des \ue9l\ue9ments cl\ue9s li\ue9s
\ue0 la conception de l\u2019\ue9tude; collection, analyse et
exploitation de donn\ue9es; et pr\ue9sentation, a \ue9t\ue9
utilis\ue9 pour guider l\u2019interrogatoire. Les r\ue9sultats ont
indiqu\ue9 que les chercheurs avaient g\ue9n\ue9ralement
d\ue9crit de mani\ue8re explicite les structures de traitement
correspondant assez bien aux objectifs et hypoth\ue8ses de
l\u2019\ue9tude (dans les cas rares o\uf9 elles avaient
\ue9t\ue9 \ue9nonc\ue9es), avec quelques faiblesses dans la
description de la structure de traitement factoriel. Le dispositif en
bloc (fisher) randomis\ue9 \ue9tait le plus couramment utilis\ue9
parmi les dispositifs, avec 3 \ue0 4 r\ue9plicats. Cependant, son
utilisation n\u2019\ue9tait gu\ue8re justifi\ue9e, car les
facteurs de blocage n\u2019\ue9taient jamais mentionn\ue9s et leur
r\uf4le dans la d\ue9termination de la pr\ue9cision des
r\ue9sultats \ue9tait donc difficile \ue0 d\ue9terminer.
L\u2019analyse de la variance \ue9tait la principale m\ue9thode
d\u2019analyse des donn\ue9es, suivie par les corr\ue9lations. Le
test F et les valeurs P associ\ue9es constituaient la base des
d\ue9cisions sur les diff\ue9rences de traitements. La plupart des
chercheurs ont eu des probl\ue8mes de pr\ue9sentation et
d\u2019interpr\ue9tation des valeurs de p et du niveau de
signification. Les tests post adhoc ont principalement utilis\ue9 la
diff\ue9rence la moins significative (DMS) pour les comparaisons
moyennes par paires, en prenant peu en compte la structure du
traitement, le nombre de traitements et la nature (qualitative ou
quantitative). En g\ue9n\ue9ral, les estimations des moyennes de
traitement \ue9taient pr\ue9sent\ue9es avec diverses mesures de
pr\ue9cision, sous forme de tableaux et de graphiques. Dans plusieurs
cas, le DMS a \ue9t\ue9 utilis\ue9 ou utilis\ue9 de
mani\ue8re interchangeable avec l\u2019erreur standard (ES) ou
l\u2019erreur standard de diff\ue9rence (ESD). Plusieurs logiciels
statistiques ont \ue9t\ue9 utilis\ue9s pour l\u2019analyse et la
pr\ue9sentation des donn\ue9es, les principaux \ue9tant SAS,
Genstat et MSTAT-C. Les points principaux d\u2019am\ue9lioration
d\ue9pendent essentiellement de l\u2019am\ue9lioration de la
capacit\ue9 des ressources humaines et infrastructurelles, plus
particuli\ue8rement de (i) la r\ue9vision p\ue9riodique des
programmes d\u2019\ue9tudes des universit\ue9s et autres
\ue9tablissements d\u2019enseignement sup\ue9rieur afin de
pr\ue9voir suffisamment de temps, un espace physique et une
infrastructure appropri\ue9e pour une v\ue9ritable mise en
pratique; (ii) une utilisation plus efficace des quelques statisticiens
disponibles dans la r\ue9gion, (iii) des cours de r\ue9outillage en
cours \ue0 court terme pour le personnel, (iv) des unit\ue9s de
services statistiques durables, le cas \ue9ch\ue9ant, et (v) la
mise en place de plates-formes interactives interactives de
statisticiens et de chercheurs ( conf\ue9rences et d\u2019ateliers
d\u2019\ue9criture) pour partager des notes sur les d\ue9fis et
les r\ue9alisations au cours de la mise en \u153uvre de leurs
programmes de recherche
Dynamics of forest cover conversion in and around Bwindi impenetrable forest, Southwestern Uganda
Forest cover has been converted to agricultural land use in and around the protected areas of Uganda. The objectives of this study were; to examine the dynamics of forest cover change in and around Bwindi impenetrable forest between 1973 and 2010 and to identify the drivers of forest cover change. The trend in forest cover change was assessed by analyzing a series of orthorectified landsat imageries of 1973, 1987 and 2001 using unsupervised and supervised classification. Land use/cover map for 2010 was reconstructed by analyzing 2001 image, validated and/or reconstructed by ground truthing, use of secondary data and key informant interviews. A series of focused group discussions and key informant interviews were also used to identify drivers of land use/cover change. Policies and institutional arrangements that could have affected forest cover change for the studied time period were also identified. Results showed that protected forest and woodlot in unprotected area had declined by 7.8% and 70.7% respectively as small scale farming and tea plantations had increased by 13.9% and 78.3% respectively between 1973 and 2010. The conversions were attributed to land use pressure due to population growth, change in socio-economic conditions and institutional arrangements. The severe loss of woodlot outside the protected area not only poses a potential threat to the protected forest but also calls for intervention measures if efforts to mitigate climate change impacts are to be realized
Limiting nutrients for bean production on contrasting soil types of Lake Victoria Crescent of Uganda
Common bean (Phaseolus vulgaris L.) is one of the most important grain legumes in East Africa, but its yield has remained below the genetic potential. Declining soil fertility is among the primary constraints to bean production in most East African bean producing regions. Often existing recommendations are generic and inept to guide farm level decision making on nutrient replenishment. A greenhouse nutrient omission study was conducted to determine the limiting nutrients in three soils of Masaka District, commonly cropped to beans: âLiddugavuâ a Phaeozem, âLimyufumyufuâ a Cambisol and âLuyinjayingaâ an Umbrisol soil. Nine treatments; (i) complete nutrient treatment, (ii) N omitted, (iii) P omitted, (iv) K omitted, (v) Mg omitted, (vi) S omitted, (vii) Ca omitted, (viii) Micronutrients omitted and (ix) control without nutrients. Each treatment was randomly assigned to the three soils and replicated three times using a completely randomised design. Nitrogen, phosphorus and potassium were limiting nutrients for bean production in Umbrisol (Luyinjayinja) while in Cambisol (âLimyufumyufu), common bean production was most limited by soil acidity. The performance varied with soil types, with beans grown on the Phaeozem registering greater leaf number and growth, confirming both scientistâs and local farmerâs knowledge that this soil has greater potential than the other two soils
Dynamics of forest cover conversion in and around Bwindi impenetrable forest, Southwestern Uganda
Forest cover has been converted to agricultural land use in and around
the protected areas of Uganda. The objectives of this study were; to
examine the dynamics of forest cover change in and around Bwindi
impenetrable forest between 1973 and 2010 and to identify the drivers
of forest cover change. The trend in forest cover change was assessed
by analyzing a series of orthorectified landsat imageries of 1973, 1987
and 2001 using unsupervised and supervised classification. Land
use/cover map for 2010 was reconstructed by analyzing 2001 image,
validated and/or reconstructed by ground truthing, use of secondary
data and key informant interviews. A series of focused group
discussions and key informant interviews were also used to identify
drivers of land use/cover change. Policies and institutional
arrangements that could have affected forest cover change for the
studied time period were also identified. Results showed that protected
forest and woodlot in unprotected area had declined by 7.8% and 70.7%
respectively as small scale farming and tea plantations had increased
by 13.9% and 78.3% respectively between 1973 and 2010. The conversions
were attributed to land use pressure due to population growth, change
in socio-economic conditions and institutional arrangements. The severe
loss of woodlot outside the protected area not only poses a potential
threat to the protected forest but also calls for intervention measures
if efforts to mitigate climate change impacts are to be realized
PARTNERSHIPS IN HIGHLANDS OF RWANDA UNDER INTEGRATED AGRICULTURAL RESEARCH FOR DEVELOPMENT (IAR4D) ARRANGEMENTS
The Integrated Agricultural Research for Development (IAR4D) concept
was proposed to respond to the failures of Agriculture Research and
Development (ARD) systems in Sub-Saharan Africa. The key element of
implementation and success of IAR4D was action sites called
agricultural Innovation Platform (IPs) and their counterfactual sites.
Social Network Analysis (SNA) is used to explain social relationships
and partnerships. This study explored the patterns of agricultural
partnerships among stakeholders in the highlands of Rwanda under IAR4D.
Data were collected in action sites that included Mudende, Gataraga,
Remera and Rwerere; and in their counterpart counterfactual sites that
comprised of Bigogwe, Nyange and Gacaca. Results showed that in action
sites, stakeholders were linked to different and diversified partners.
Furthermore, many stakeholders were connected to several partners
through agricultural partnerships, hence creating complex social
networks with high density and degree of distribution. In the
counterfactual sites, however, stakeholders were exclusively linked to
the same kind of partners, and one stakeholder was connected to one
partner through probably non-agricultural partnerships. These facts
demonstrated that IAR4D created dense interfaces, significantly
improved the networking system, and delivered technologies and
innovations.Le concept de Recherche Agricole Int\ue9gr\ue9e pour le
D\ue9veloppement (IAR4D) a \ue9t\ue9 propos\ue9 comme solution
aux \ue9checs des syst\ue8mes Recherches Agricoles et
D\ue9veloppement (ARD) en Afrique Sub-Saharienne.
L\u2019\ue9l\ue9ment principal de la r\ue9ussite et du
succ\ue8s d\u2019IAR4D \ue9tait l\u2019\ue9tablissement des
sites d\u2019action appel\ue9s Plateformes Agricoles
d\u2019innovation (IPs) ainsi que leurs sites t\ue9moins.
L\u2019analyse du R\ue9seau Sociale (SNA) est utilis\ue9e pour
expliquer les rapports et les relations sociaux des acteurs et des
partenaires. La pr\ue9sente \ue9tude avait pour objectif
d\u2019explorer les structures des relations socio-agricoles parmi les
acteurs et les partenaires dans les hautes altitudes du Rwanda soumises
\ue0 l\u2019IAR4D. Les donn\ue9es ont \ue9t\ue9
r\ue9colt\ue9es dans les sites d\u2019action comprenant\ua0:
Mudende, Gataraga, Remera et Rwerere ainsi que dans leurs contreparties
sites t\ue9moins incluant Bigogwe, Nyange et Gacaca. Les
r\ue9sultats ont montr\ue9 que dans les sites d\u2019action, les
acteurs \ue9taient associ\ue9s aux partenaires de natures
diff\ue9rentes et un acteur \ue9tait li\ue9 \ue0 plusieurs
partenaires a la fois. Dans les sites t\ue9moins par contre, les
acteurs \ue9taient li\ue9s aux partenaires de m\ueames natures
que ceux-ci et un acteur \ue9tait rarement li\ue9 \ue0 plus de
deux partenaires. Ces faits ont montr\ue9 que l\u2019IAR4D a
cr\ue9e un r\ue9seau socio-agricole tr\ue8s dense et
sophistiqu\ue9 et ainsi a consid\ue9rablement am\ue9lior\ue9 le
r\ue9seau socio-agricole. Par cons\ue9quent, l\u2019IAR4D peut
\ueatre recommand\ue9 pour le transfert the technologies and des
innovations agricoles
LAND USE/COVER CHANGE PATTERNS IN HIGHLAND ECOSYSTEMS OF LAKE BUNYONYI CATCHMENT IN WESTERN UGANDA
Land use and cover changes influence the livelihood and degradation of
fragile ecosystems. The extents of these changes in pattern were
investigated in Lake Bunyonyi Catchment which lies in the South Western
Highlands of Uganda. The dynamics and magnitude of land use and cover
changes were assessed using Landsat (TM/ETM+) satellite images and
collection of socio-economic data through interviews. The images were
processed and analysed using the mean-shift image segmentation
algorithm to cluster and quantify the land use and cover features. The
study noted that in the assessment period 1987-2014, the small-scale
farmlands, open water and grasslands remained quasi constant; while the
woodlots followed a quadratic trend, with the lowest acreage
experienced in 2000. The tropical high forests and wetlands cover types
experienced significant decline over the years (P<0.05). Patches of
small-scale farmlands, woodlots, and wetland interchangeably lost or
gained more land dependant on climate variability. Even though the
tropical high forest lost more than it gained, it only gained and lost
to small scale farmland and woodlots; while grassland mainly lost to
small scale farmland and woodlots.L\u2019occupation du sol et les changements de couverture influencent
la subsistance et la d\ue9gradation des \ue9cosyst\ue8mes
fragiles. La tendance des niveaux de ces changements \ue9taient
\ue9valu\ue9e dans le basin versant du lac Bunyonyi qui relie les
r\ue9gions montagneuses du Sud-Ouest d\u2019Ouganda. Les dynamiques
et l\u2019 envergure d\u2019utilisaton de la terre et les changements
de couverture \ue9taient \ue9valu\ue9es en utilisant les images
du satellite Landsat (TM/ETM+) et la collecte des donn\ue9es
socio-\ue9conomiques \ue0 travers des interviews. Les images
\ue9taient trait\ue9es et analy\ue9es en utilisant
l\u2019algorithme de segmentation de passage-moyen-d\u2019image pour
grouper et quantifier les occupations du sol et les
caract\ue9ristiques de la couverture. L\u2019\ue9tude a
montr\ue9 que dans la p\ue9riode d\u2019\ue9valuation de
1987-2014, la petite \ue9tendue de terres cultivables, l\u2019eau
libre et les prairies sont demeur\ue9es quasi constantes; tandis que
les terres bois\ue9es ont suivi une tendance quadratique, avec la
plus petite superficie observ\ue9e en l\u2019an 2000. Les grandes
for\ueats tropicales et les zones humides ont exp\ue9riment\ue9
un d\ue9clin significatif au cours des ann\ue9es (P<0.05). Les
petites parcelles de terres agricoles, les terres bois\ue9es, et les
zones humides indistinctement ont perdu et gagn\ue9 plus de terres
d\ue9pendamment de la variabilit\ue9 climatique. Bien que la grande
for\ueat tropicale aie perdu plus qu\u2019elle en a gagn\ue9e;
elle a seulement perdu de tr\ue8s petites \ue9tendues de terres
agricoles et bois\ue9es; alors que les prairies ont principalement
perdu de tr\ue8s petites \ue9tendues de terres agricoles et
bois\ue9es
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