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

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

Single blinded semi-field evaluation of MAÏA® topical repellent ointment compared to unformulated 20% DEET against Anopheles gambiae, Anopheles arabiensis and Aedes aegypti in Tanzania.

BACKGROUND: N,N-Diethyl-3-methylbenzamide (DEET) topical mosquito repellents are effective personal protection tools. However, DEET-based repellents tend to have low consumer acceptability because they are cosmetically unappealing. More attractive formulations are needed to encourage regular user compliance. This study evaluated the protective efficacy and protection duration of a new topical repellent ointment containing 15% DEET, MAÏA® compared to 20% DEET in ethanol using malaria and dengue mosquito vectors in Bagamoyo Tanzania. METHODS: Fully balanced 3 × 3 Latin square design studies were conducted in large semi-field chambers using laboratory strains of Anopheles gambiae sensu stricto, Anopheles arabiensis and Aedes aegypti. Human volunteers applied either MAÏA® ointment, 20% DEET or ethanol to their lower limbs 6 h before the start of tests. Approximately 100 mosquitoes per strain per replicate were released inside each chamber, with 25 mosquitoes released at regular intervals during the collection period to maintain adequate biting pressure throughout the test. Volunteers recaptured mosquitoes landing on their lower limbs for 6 h over a period of 6 to 12-h post-application of repellents. Data analysis was conducted using mixed-effects logistic regression. RESULTS: The protective efficacy of MAÏA® and 20% DEET was not statistically different for each of the mosquito strains: 95.9% vs. 97.4% against An. gambiae (OR = 1.53 [95% CI 0.93-2.51] p = 0.091); 96.8% vs 97.2% against An. arabiensis (OR = 1.08 [95% CI 0.66-1.77] p = 0.757); 93.1% vs 94.6% against Ae. aegypti (OR = 0.76 [95% CI 0.20-2.80] p = 0.675). Average complete protection time (CPT) in minutes of MAÏA® and that of DEET was similar for each of the mosquito strains: 571.6 min (95% CI 558.3-584.8) vs 575.0 min (95% CI 562.1-587.9) against An. gambiae; 585.6 min (95% CI 571.4-599.8) vs 580.9 min (95% CI 571.1-590.7) against An. arabiensis; 444.1 min (95% CI 401.8-486.5) vs 436.9 min (95% CI 405.2-468.5) against Ae. aegypti. CONCLUSIONS: MAÏA® repellent ointment provides complete protection for 9 h against both An. gambiae and An. arabiensis, and 7 h against Ae. aegypti similar to 20% DEET (in ethanol). MAÏA® repellent ointment can be recommended as a tool for prevention against outdoor biting mosquitoes in tropical locations where the majority of the people spend an ample time outdoor before going to bed

Water use efficiency of maize (Zea mays L.) crop under selected soil and water conservation practices along the slope gradient in Ruzizi watershed, eastern D.R. Congo

Open Access Journal; Published online: 18 Oct 2022Maize (Zea mays L.) productivity is constrained by water shortages in the predominantly rainfed agriculture of the tropical semi-arid Ruzizi Plain, in the eastern Democratic Republic of Congo (DRC). The region is characterized by a high seasonal and inter-annual rainfall variability and a frequent occurrence of consecutive dry days within growing seasons. Consequently, planning water utilization in rainfed agriculture has become complex, as appropriate soil water conservation (SWC) practices are lacking among most smallholder farmers. Identifying practices that increase water use efficiency (WUE) along the slope gradient is crucial for supporting maize production in the region. In this study, we assessed, for three growing seasons, the effectiveness of two SWC practices (tied ridges and Zai pits) in improving the WUE of two maize varieties along three slope gradients (0–2, 2–8, and 8–15%) in the tropical semi-arid Ruzizi Plain. In this area, rainfall amounts (142–289 mm) were consistently below the evapotranspiration demands (356–533 mm) across the three growing seasons. Tied ridges recorded the highest grain yield (2.16 t ha−1) and WUE (15.23 kg mm−1), especially at low slopes, when compared to Zai pits and conventional tillage. For all SWC practices, WUE decreased with the slope gradient (p < 0.01). Furthermore, a decrease in stored soil water (SWS) at silking and maturity stages (milk, dough, and dent stages) negatively affected the WUE. The variety had no significant effect on grain yield and WUE. Root biomass (RBM), shoot biomass (SBM), and leaf area index (LAI) at the flowering stage were the most associated with the WUE (R2 = 58.5%). In conclusion, tied ridges showed potential for improving maize WUE and yield in the water-deficient conditions that characterize the Ruzizi Plain, and could be promoted to improve the maize productivity among smallholder farmers