Van Asten P.J.A.,International Institute Of Tropical Agriculture |
Wairegi L.W.I.,International Institute Of Tropical Agriculture |
Wairegi L.W.I.,Makerere University |
Bagamba F.,Kawanda Agricultural Research Institute |
Drew C.,USAID Agricultural Productivity Enhancement Program
Acta Horticulturae | Year: 2010
Low soil fertility is among the important factors limiting highland banana (Musa spp., AAA-EA genome) yields in Uganda. We monitored 179 on-farm demonstration and control plots in Central, South, Southwest and East Uganda to identify constraints and opportunities to fertilizer adoption in banana systems. Demonstration plots received on average 71-8-32 kg ha -1 y -1 of N-P-K fertilizers. Most plots (53%) received external mulch, whereas farmer control plots received no fertilizer and little external mulch (13% of the plots). The demonstration plots were used for learning by nearby collaborating farmers. Structured interviews were conducted to get information on farmer perceptions of demonstrated technologies. Farmers observed that demonstration plots had consistently higher yields than control plots due to bigger bunches and better quality. Yield increases varied from 3.5 t ha -1 y -1 in Luwero (Central Uganda) to 13.1 t ha -1 y -1 in Masaka (South Uganda). Fertilizer use was highly profitable at sites close to Kampala market but not at sites far away (>250 km). The marginal rates of return exceeded 575% in Wakiso district (Central Uganda) but only averaged 10% in Bushenyi (Southwest Uganda). Foliar analysis indicated that fertilizer use will become more profitable when site-specific plant nutrient deficiencies are targeted. Farmers perceived fertilizer prices as the most important constraint to adoption, despite limited knowledge of actual prices. Other important constraints perceived by farmers were poor supply, labor required for fertilizer application, and the belief that fertilizer negatively affected soil quality. The demonstration plot approach simultaneously allowed participatory evaluation, fine-tuning and adoption and adaptation of fertilizer recommendations. This approach shortens and strengthens the adoption pathway, provided the process is supported by proper agronomic and economic evaluation of the technologies tested.
PubMed | Environment Canada, Kawanda Agricultural Research Institute, Makerere University and AirZoneOne Inc.
Type: Journal Article | Journal: The Science of the total environment | Year: 2015
The Lake Victoria watershed has extensive agricultural activity with a long history of pesticide use but there is limited information on historical use or on environmental levels. To address this data gap, high volume air samples were collected from two sites close to the northern shore of Lake Victoria; Kakira (KAK) and Entebbe (EBB). The samples, to be analyzed for pesticides, were collected over various periods between 1999 and 2004 inclusive (KAK 1999-2000, KAK 2003-2004, EBB 2003 and EBB 2004 sample sets) and from 2008 to 2010 inclusive (EBB 2008, EBB 2009 and EBB 2010 sample sets). The latter sample sets (which also included precipitation samples) were also analyzed for currently used pesticides (CUPs) including chlorpyrifos, chlorthalonil, metribuzin, trifluralin, malathion and dacthal. Chlorpyrifos was the predominant CUP in air samples with average concentrations of 93.5, 26.1 and 3.54 ng m(-3) for the EBB 2008, 2009, 2010 sample sets, respectively. Average concentrations of total endosulfan (Endo), total DDT related compounds (DDTs) and hexachlorocyclohexanes (HCHs) ranged from 12.3-282, 22.8-130 and 3.72-81.8 pg m(-3), respectively, for all the sample sets. Atmospheric prevalence of residues of persistent organic pollutants (POPs) increased with fresh emissions of endosulfan, DDT and lindane. Hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and dieldrin were also detected in air samples. Transformation products, pentachloroanisole, 3,4,5-trichloroveratrole and 3,4,5,6-tetrachloroveratrole, were also detected. The five most prevalent compounds in the precipitation samples were in the order chlorpyrifos>chlorothalonil>Endo>DDTs>HCHs with average fluxes of 1123, 396, 130, 41.7 and 41.3 ng m(-2)sample(-1), respectively. PeCB exceeded HCB in precipitation samples. The reverse was true for air samples. Backward air trajectories suggested transboundary and local emission sources of the analytes. The results underscore the need for a concerted regional vigilance in management of chemicals.
Rossmann B.,University of Graz |
Muller H.,University of Graz |
Smalla K.,Julius Kuhn Institute |
Mpiira S.,Kawanda Agricultural Research Institute |
And 3 more authors.
Applied and Environmental Microbiology | Year: 2012
Bananas are among the most widely consumed foods in the world. In Uganda, the country with the second largest banana production in the world, bananas are the most important staple food. The objective of this study was to analyze banana-associated microorganisms and to select efficient antagonists against fungal pathogens which are responsible for substantial yield losses. We studied the structure and function of microbial communities (endosphere, rhizosphere, and soil) obtained from three different traditional farms in Uganda by cultivation-independent (PCR-SSCP fingerprints of 16S rRNA/ITS genes, pyrosequencing of enterobacterial 16S rRNA gene fragments, quantitative PCR, fluorescence in situ hybridization coupled with confocal laser scanning microscopy, and PCR-based detection of broad-host-range plasmids and sulfonamide resistance genes) and cultivation-dependent methods. The results showed microhabitat-specific microbial communities that were significant across sites and treatments. Furthermore, all microhabitats contained a high number and broad spectrum of indigenous antagonists toward identified fungal pathogens. While bacterial antagonists were found to be enriched in banana plants, fungal antagonists were less abundant and mainly found in soil. The banana stem endosphere was the habitat with the highest bacterial counts (up to 109 gene copy numbers g-1). Here, enterics were found to be enhanced in abundance and diversity; they provided one-third of the bacteria and were identified by pyrosequencing with 14 genera, including not only potential human (Escherichia, Klebsiella, Salmonella, and Yersinia spp.) and plant (Pectobacterium spp.) pathogens but also disease-suppressive bacteria (Serratia spp.). The dominant role of enterics can be explained by the permanent nature and vegetative propagation of banana and the amendments of human, as well as animal, manure in these traditional cultivations. © 2012, American Society for Microbiology.
Farrow A.,Kawanda Agricultural Research Institute |
Risinamhodzi K.,Chitedze Research Station |
Zingore S.,Chitedze Research Station |
Zingore S.,International Plant Nutrition Institute |
Delve R.J.,Chitedze Research Station
Agricultural Systems | Year: 2011
Developing the rural agricultural input markets in sub-Saharan Africa can improve the current low productivity of smallholder farmers. Malawi has seen significant efforts in addressing the availability of agricultural inputs at village level in the last few years; for example, the improvement of rural agro-dealer networks. Nevertheless inputs are still difficult to obtain for many remote smallholder farmers. Spatial analysis can help in the expansion of input stockists, especially agro-dealer networks, by assessing the coverage of existing input outlets and deriving optimum locations for village-level input stockists.We address three research questions. First, what is the locational efficiency of the current village-level stockists of inputs (Citizens Network for Foreign Affairs - Rural Agricultural Market Development Trust trained network of agro dealers and public sector)? Secondly, how many village-level stockists of markets are needed to reach 60% of the population in the central region of Malawi within one hour? Finally we address the potential spatial components of the sustainability of input stockists relating to the potential demand from smallholder farmers and the access to bulk supplies. The problem of finding the optimum location for village-level stockists of markets is addressed in two stages, using spatial analysis in conjunction with location-allocation models. First, the locational efficiency of the existing network of stockists of inputs is determined, followed by the establishment of a set of optimal sites for village-level stockists of inputs. A final step explores the viability of stockists and calculates the population surrounding the stockists taking into account competition from other sources of inputs and the accessibility of the selected stockists to potential wholesalers who are bulk distributors of farm inputs.Our results show that locational efficiency can be assessed in terms of the differential access of households to resources and transport. Often, these differences are not considered in covering problems and can have a large effect on the physical access to inputs. The results can be used to define which areas are inherently difficult to serve with agricultural inputs and could inform efforts to provide incentives to remote areas. Further implications for input policies in Malawi are that improvements in road infrastructure might not directly benefit the poorest farmers (if they are walking) but could serve to reduce the wholesale prices and therefore the retail price. In addition, the improvement in roads might increase the number of potential customers of any particular stockist, with economies of scale allowing the reduction of prices while ensuring a satisfactory profit margin for the stockist. The results of our models imply that Citizens Network for Foreign Affairs may need to train stockists over a wider area to increase the access to inputs of those smallholder farmers with least resources. © 2011 Elsevier Ltd.
Karamura D.,Bioversity International |
Kiggundu A.,Kawanda Agricultural Research Institute |
Karamura E.,Bioversity International
Acta Horticulturae | Year: 2011
Farmers in East Africa help shape the degree of genetic diversity in banana landraces. They describe cultivars by names related to one or more traits at various development stages of the plant life cycle, like agronomic performance, uses of plant parts or aesthetics. This allows farmers to categorise diversity using relevant morphological criteria to create a pattern of naming and grouping cultivars. Factors farmers use to describe and name cultivars are interrelated and provide a set of agro-morphological criteria which define a landrace. Not much is known about the structure of farmers' nomenclature of these landraces and its relevance to the botanical descriptors and classification. This paper describes a study which was undertaken in two culturally different banana-growing communities in Uganda, Luwero in mid altitudes and Mbale in high altitudes. The purpose of the study was: (1) to identify the traits farmers use in describing and naming cultivars of East African highland banana; (2) to compare farmers' and botanical descriptors to assess the relationship between the two; and (3) to determine the biological usefulness of the farmers' system. Three methods were used: an informal participatory method to provide preliminary information on descriptors; a quantitative ranking of the results of the participatory method; and multivariate statistics to discover the relationship between the two types of descriptors by comparing the categorisations resulting from the descriptor analysis. Results indicated that the most important farmer descriptors fall into five categories: size and shape, texture, appearance, agronomic and commercial aspects. There was more than 60% correlation between farmers' grouping of cultivars (based on fewer descriptors) and botanical classification (based on many descriptors). In conclusion, farmers' grouping resulting from their descriptors had a biological meaning while the botanical classification reflected the practices of local people.
Studholme D.J.,University of Exeter |
Studholme D.J.,Sainsbury Laboratory |
Kemen E.,Sainsbury Laboratory |
MacLean D.,Sainsbury Laboratory |
And 6 more authors.
FEMS Microbiology Letters | Year: 2010
Banana Xanthomonas wilt is a newly emerging disease that is currently threatening the livelihoods of millions of farmers in East Africa. The causative agent is Xanthomonas campestris pathovar musacearum (Xcm), but previous work suggests that this pathogen is much more closely related to species Xanthomonas vasicola than to X. campestris. We have generated draft genome sequences for a banana-pathogenic strain of Xcm isolated in Uganda and for a very closely related strain of X. vasicola pathovar vasculorum, originally isolated from sugarcane, that is nonpathogenic on banana. The draft sequences revealed overlapping but distinct repertoires of candidate virulence effectors in the two strains. Both strains encode homologues of the Pseudomonas syringae effectors HopW, HopAF1 and RipT from Ralstonia solanacearum. The banana-pathogenic and non-banana-pathogenic strains also differed with respect to lipopolysaccharide synthesis and type-IV pili, and in at least several thousand single-nucleotide polymorphisms in the core conserved genome. We found evidence of horizontal transfer between X. vasicola and very distantly related bacteria, including members of other divisions of the Proteobacteria. The availability of these draft genomes will be an invaluable tool for further studies aimed at understanding and combating this important disease. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Schluter U.,University of Pretoria |
Schluter U.,Laval University |
Benchabane M.,Laval University |
Munger A.,Laval University |
And 6 more authors.
Journal of Experimental Botany | Year: 2010
Protease inhibitors are a promising complement to Bt toxins for the development of insect-resistant transgenic crops, but their limited specificity against proteolytic enzymes and the ubiquity of protease-dependent processes in living organisms raise questions about their eventual non-target effects in agroecosystems. After a brief overview of the main factors driving the impacts of insect-resistant transgenic crops on non-target organisms, the possible effects of protease inhibitors are discussed from a multitrophic perspective, taking into account not only the target herbivore proteases but also the proteases of other organisms found along the trophic chain, including the plant itself. Major progress has been achieved in recent years towards the design of highly potent broad-spectrum inhibitors and the field deployment of protease inhibitor-expressing transgenic plants resistant to major herbivore pests. A thorough assessment of the current literature suggests that, whereas the non-specific inhibitory effects of recombinant protease inhibitors in plant food webs could often be negligible and their 'unintended' pleiotropic effects in planta of potential agronomic value, the innocuity of these proteins might always remain an issue to be assessed empirically, on a case-by-case basis. © 2010 The Author.
Farrow A.,Kawanda Agricultural Research Institute |
Musoni D.,Kawanda Agricultural Research Institute |
Cook S.,Kawanda Agricultural Research Institute |
Cook S.,University of Western Australia |
Buruchara R.,Kawanda Agricultural Research Institute
Experimental Agriculture | Year: 2011
This paper seeks to establish the concept that the analysis of high temporal resolution meteorological data adds value to the investigation of the effect of climatic variability on the prevalence and severity of agricultural pests and diseases. Specifically we attempt to improve disease potential maps of root rots in common beans, based on a combination of inherent susceptibility and the risk of exposure to critical weather events. We achieve this using simulated datasets of daily rainfall to assess the probability of heavy rainfall events at particular times during the cropping season. We then validate these simulated events with observations from meteorological stations in East Africa. We also assess the utility of remotely sensed daily rainfall estimates in near real time for the purposes of updating the risks of these events over large areas and for providing warnings of potential disease outbreaks. We find that simulated rainfall data provide the means to assess risk over large areas, but there are too few datasets of observed rainfall to definitively validate the probabilities of heavy rainfall events generated using rainfall simulations such as those generated by MarkSim. We also find that selected satellite rainfall estimates are unable to predict observed rainfall events with any power, but data from a sufficiently dense network of rain gauges are not available in the region. Despite these problems we show that remotely sensed rainfall estimates may provide a more realistic assessment of rainfall over large areas where rainfall observations are not available, and alternative satellite estimates should be explored. © 2011 Cambridge University Press.
De Meyer A.,Catholic University of Leuven |
Poesen J.,Catholic University of Leuven |
Isabirye M.,Kawanda Agricultural Research Institute |
Deckers J.,Catholic University of Leuven |
Raes D.,Catholic University of Leuven
Catena | Year: 2011
In an effort to pinpoint the sources of sediment pollution in Lake Victoria, the contribution of sediment from compounds, landing sites, unpaved roads and footpaths is determined in the catchment of Nabera Bay and Kafunda Bay at the northern shore of Lake Victoria in southern Uganda. The volume of soil loss is determined in 36 compounds, 1 school and 1 landing site by comparing the original and current soil surface. The original soil surface is reconstructed using botanical and man-made datable objects. The soil loss rates are calculated by dividing the eroded soil volume by the age of the oldest datable object. Considering all compounds and landing sites in the study area, the average soil loss rate in compounds amounts to 107Mgha-1year-1 (per unit compound) and to 207Mgha-1year-1 per unit landing site. The soil loss from footpaths and unpaved roads is calculated by multiplying the total length of footpaths and unpaved roads with the average width and soil loss depth. The mean soil loss rate on footpaths is 34Mgha-1year-1 and on unpaved roads equals 35Mgha-1year-1. Compounds, landing sites, footpaths and unpaved roads occupy a small fraction of the study area (2.2%), but contribute disproportionately to the total soil loss (i.e. 85%) in the study area. It is concluded that compounds, landing sites, footpaths and unpaved roads are very significant sources of sediment pollution to Lake Victoria. This needs to be considered when designing strategies to reduce sediment production in the area. © 2010 Elsevier B.V.
Ngambeki D.,Kawanda Agricultural Research Institute |
Nowakunda K.,Kawanda Agricultural Research Institute |
Tushemereirwe W.K.,Kawanda Agricultural Research Institute
Acta Horticulturae | Year: 2010
The banana (Musa spp.) marketing system in Uganda is very complex, with a long value chain of actors from farmers to consumers. A market study was conducted in eight districts from central, eastern and western Uganda to assess the extent to which upcountry middlemen in the market chain affect farmers' prices and the distribution of price margins. The results indicated that 70% of farmers market their produce through middlemen, receiving Ugsh (Ugandan Shillings) 1,408/bunch ($1 = 1,750 Ugsh), equivalent to 28% of wholesalers' price at the nearest loading center. This implied that some of the agents and brokers shared part of the farmgate prices and reduced farmers' prices by 72%. Analysis of banana market shares and gross margins in central and western Uganda showed that upcountry agents and brokers obtained a market share of 35% out of the consumer market price, while farmers' market share was only 20%. About 11% of farmers were selling as informal groups, obtaining 44% of the wholesalers' price at the nearest loading center. Only 19% of the farmers organized into collective marketing groups. Selling directly to wholesalers or contracted buyers earned Ugsh 3,360/bunch, equivalent to 67% of the wholesalers' price at the nearest loading center. Those farmers were also able to raise large volumes of 520, 622 and 420 bunches/month from the central, eastern and western region, respectively and attracted bulk buyers with higher prices. The individual farmers could only sell small volumes of 44, 18 and 56 bunches/month in the same eastern, central and western regions and were unable to attract large scale buyers. We conclude that selling individually through middlemen incurs a loss of Ugsh 913,536/year/farmer due to farmgate price distortions by middlemen.