National Agricultural Research Laboratories NARL

Box Elder, United States

National Agricultural Research Laboratories NARL

Box Elder, United States
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Kaizzi K.C.,National Agricultural Research Laboratories NARL | Byalebeka J.,National Agricultural Research Laboratories NARL | Semalulu O.,National Agricultural Research Laboratories NARL | Alou I.,National Agricultural Research Laboratories NARL | And 3 more authors.
Agronomy Journal | Year: 2012

Sorghum [Sorghum bicolor (L.) Moench] is important for smallholder production in semiarid parts of Uganda. Grain yields are low because of low soil fertility. Little fertilizer is used. Yield response to N, P, and K application, economically optimal rates for N, P, and K (EONR, EOPR, and EOKR, respectively), and N use efficiency (NUE) were evaluated at 11 site-seasons. Mean sorghum yield with no N applied (N 0) was 0.69 Mg ha -1 and was consistently increased by a mean of 230% with N application. Mean EONRs were 34 to 18 kg ha -1 N with fertilizer use cost to grain price ratios (CPs) of 10 to 30, respectively. Mean EOPRs were 11 to 2 kg ha -1 P with CPs of 10 to 50, respectively. Sorghum did not respond to K application. Net economic returns were greater for N than P application. Mean aboveground biomass N with0 and 90 kg ha -1 N applied was 31. 3 and 75.9 kg ha -1, respectively. Grain N concentration, N harvest index, and internal NUE at the EONR were 1.67%, 53.2%, and 31.8 kg kg -1, respectively, and higher than for N0. Mean recovery efficiency, partial factor productivity, and agronomic efficiency declined with increased N rate and were 135%, 79 kg kg -1, and 52 kg kg -1, respectively, at the EONR. The profit potential of fertilizer N use is high for smallholder sorghum production in Uganda. Policy interventions to reduce fertilizer cost and improve grain marketing efficiency will enable smallholders to increase fertilizer use for substantial increases in sorghum production. © 2012.


Mutyaba C.,National Agricultural Research Laboratories NARL | Lubinga M.H.,Agricultural Research Council | Ogwal R.O.,National Agricultural Research Laboratories NARL | Tumwesigye S.,National Agricultural Research Laboratories NARL
Journal of Agriculture and Rural Development in the Tropics and Subtropics | Year: 2016

We aim at mapping out a detailed framework that reveals the proportionate flow of cassava and its products along the value chain (VC). Furthermore, we aim at establishing the role of institutions and the linkages between institutions and other VC actors that influence the cassava VC in Uganda. We use both primary and secondary data obtained from four regions in Uganda. Results show that farmers, processors, transporters, traders, consumers and institutions are the major actors. There are four categories of institutions, viz, government, non-government, community based organisations and international agencies. Roles performed by institutions include: development and enforcement of policies, Research and Development (R&D), capacity building, and creation of market access linkages for cassava and its products. Findings reveal that there is no clear nexus and no coordination among farmers/producers, processors, traders, transporters and consumers. However, institutions are well coordinated and play various roles along the VC to influence the dynamics of actors. Policy-wise it is important to establish strong private-public partnerships to bridge the impaired linkages between the actors (farmers/producers, processors, traders, transporters, and consumers) and institutions. Strong partnerships are envisaged to reduce the associated transaction costs amongst the actors. © 2016, Kassel University Press GmbH. All rights reserved.


Isabirye B.E.,Makerere University | Isabirye B.E.,Association for Strengthening Agricultural Research in Eastern and Central Africa ASARECA | Akol A.M.,Makerere University | Mayamba A.,National Agricultural Research Laboratories NARL | And 2 more authors.
International Journal of Tropical Insect Science | Year: 2015

The species diversity of tephritid fruit flies in major mango-growing regions in Uganda was monitored over a 2-year period (2010-2012) using fruit bait and lure traps. A total of 368,332 specimens belonging to 10 species in four genera (Bactrocera, Ceratitis, Trirhithrum and Dacus) were collected. Of these, 98.9% belonged to Bactrocera invadens, while the second and third most common species were Dacus bivittatus (0.4%) and Ceratitis anonae (0.3%), respectively. Significant differences in the evenness and diversity of fruit fly species were noted across the regions. Fruit fly community structure was significantly different across the three regions. The Lake Victoria Crescent and Mbale Farmlands harboured significantly more D. ciliatus, T. coffeae, D. bivittatus and B. cucurbitae in contrast to the Northern Moist Farmlands and the Western Medium High Farmlands. Ceratitis rosa contributed the highest difference in regional structure, followed by C. fasciventris and C. cosyra. Rank abundance curves depicted a geometric series distribution of the species composition in the three regions, confirming a scenario of competitive displacement of native fruit fly species by B. invadens. A comprehensive and sustainable response strategy to B. invadens and other fruit flies needs to be urgently devised to protect the horticulture industry in Uganda. Copyright © ICIPE 2015.


Bechoff A.,University of Greenwich | Westby A.,University of Greenwich | Owori C.,National Agricultural Research Laboratories NARL | Menya G.,National Agricultural Research Laboratories NARL | And 4 more authors.
Journal of the Science of Food and Agriculture | Year: 2010

BACKGROUND: Orange-fleshed sweetpotato(OFSP)can be used to tackle vitamin A deficiency, a major public health problem in most developing countries. In East Africa, common ways of using sweetpotato include drying and subsequent storage. The aim of the study was to investigate the impact of drying and storage on the total carotenoid retention (as an estimate of provitamin A retention) from OFSP. RESULTS: Losses of total carotenoid during drying were generally low (15% or less). Total carotenoid retention in OFSP was not dependent on the type of dryer (solar or sun). Sweetpotato cultivar (Ejumula, Kakamega, SPK004/1, SPK004/1/1, SPK004/6 or SPK004/6/6) had a significant effect on retention in drying (P < 0.05). High percentage losses of total carotenoids were, however, correlated with high moisture content and high carotenoid content in fresh sweetpotato roots. After 4 months' storage at room temperature in Uganda, losses of total carotenoid in dried sweetpotato chips were high (about 70%) and this was not dependent on the use of opaque or transparent packaging. CONCLUSION: Losses of carotenoids during storage were considered to be more of a nutritional constraint to the utilisation of dried sweetpotato than losses occurring during drying. The relationship between characteristics of the cultivars and losses of carotenoids during drying should be taken into account in selection of cultivars for processing. © 2009 Society of Chemical Industry.


Bechoff A.,University of Greenwich | Poulaert M.,CIRAD - Agricultural Research for Development | Tomlins K.I.,University of Greenwich | Westby A.,University of Greenwich | And 3 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

The retention and bioaccessibility of β-carotene (BC) in blended foods made with part orange-fleshed sweet potato (OFSP) flour (30%) were examined. Chapatis and porridges were prepared by local processors under field conditions (FC) in Uganda (n = 10). While the retention of all-trans-BC in porridges (69 to 93%) and chapatis (70 to 97%) varied between the processors, there was no overall difference between the two products and this was probably because of the variability in FC. BC retention in mandazis was similar to that of chapatis and porridges. Processing in FC significantly increased the amount of cis-isomers, in particular 13-cis-BC. The bioaccessibility of the BC as measured by their transfer into micelles was evaluated using an in vitro digestion procedure in various OFSP-derived products. After in vitro digestion, the percentage of micellarized all-trans-BC was greater in products cooked with oil, chapati (73%) and mandazi (49%), as compared with the boiled ones, porridge (16%) and puréed from boiled root (10%). In all the products, the incorporation into micelles for 13-cis-BC was significantly higher to that of all-trans-BC. When taking into account the bioaccessibility of all-trans-BC and 13-cis-BC isomer, an edible portion of porridge (one mug), boiled root (half a root), mandazis (two), or chapati (one) could provide a significant part of the daily vitamin A requirements of a child under 6 years (respectively 20, 46, 75, or 100%). These data support the promotion/consumption of locally cooked OFSP food products to tackle vitamin A deficiency in sub-Saharan Africa. © 2011 American Chemical Society.


Bechoff A.,University of Greenwich | Westby A.,University of Greenwich | Menya G.,National Agricultural Research Laboratories NARL | Tomlins K.I.,University of Greenwich
Journal of Food Quality | Year: 2011

Various dipping pretreatments have been investigated for orange-fleshed sweet potato (OFSP) to retain carotenoids after drying and subsequent storage. Effects of blanching, sodium metabisulfite (0.5 or 1%), acids (ascorbic acid [1%] or citric acid [0.5%]) or salt (1%), either singly or as mixtures, were tested on dried OFSP chips that were stored for up to 6 months in ambient conditions. Overall, there was a positive effect of dipping on total carotenoid content after drying compared with control (P<0.05). A slight improvement in carotenoid content was observed during the first month of storage with ascorbic acid, sodium metabisulfite, and mixtures of sodium metabisulfite and citric acid, or ascorbic acid and salt pretreatments, but these higher levels were not maintained over longer storage periods (4-6 months). The general lack of improvement was believed to result from the leaching and degradation of the chemicals during storage. © 2011 Wiley Periodicals, Inc..

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