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Tesfahunegn G.B.,Aksum University | Tesfahunegn G.B.,University of Bonn | Tamene L.,Chitedze Agricultural Research Station | Vlek P.L.G.,University of Bonn | Mekonnen K.,Aksum University
Land Degradation and Development | Year: 2016

Soil quality (SQ) assessment from farmers' point of view can be used as a primary indicator for planning sustainable agriculture. Despite this fact, limited information is documented with regard to SQ indicators, for example weed species, crop types and management practices from farmers' knowledge perspectives. The aims of this study are to analyse factors that determine farmers' knowledge of SQ, identify SQ indicators of weed species and crop types across different SQ status and assess soil-and-crop management practices that maintain SQ in the Mai-Negus catchment, northern Ethiopia. Fifty-two farmer household heads were chosen randomly for questionnaire interview. The results showed significant (p≤0·05) differences in the proportion of respondents who used different crop-and-soil management practices. The success of overall prediction by the logistic regression model (model χ2=0·84, p<0·01) and level of model correct predictions (86%) indicated that the explanatory variables have sufficiently explained farmers' knowledge of SQ indicators. Provided that other conditions remained constant, the odds ratio of variables such as farmer experience, access to information, farm location, education, field slope and land tenure have significantly increased the likelihood of farmers for being knowledgeable of SQ indicators. This study also demonstrated that most farmers are knowledgeable in identifying weed species, crop types and management practices across various SQ status, which suggests that such SQ indicators should be used to assess SQ status (degradation severity) while locating fields to be intervened using appropriate management strategies. © 2013 The Authors. Land Degradation & Development published by John Wiley & Sons, Ltd. © 2016 John Wiley & Sons, Ltd. Source


Matumba L.,University of Malawi | Matumba L.,Chitedze Agricultural Research Station | Monjerezi M.,University of Malawi | Van Poucke C.,Ghent University | And 3 more authors.
World Mycotoxin Journal | Year: 2013

The bright greenish yellow fluorescence (BGYF) test has been used with varying success in screening for aflatoxins in maize. This test was applied to 180 maize samples collected from different markets within 12 districts of Malawi in order to evaluate its performance against high performance liquid chromatographic analysis. The number of BGYF grains in 2.5 kg unground samples ranged from 0 to 35 and about 49% of all tested samples had aflatoxin concentrations ranging from 1 to 382 μg/kg. A total of 65 (36%) of the examined unground samples showed no BGYF. The European Commission recommends a false negative rate of less than 5% for a screening technique to be acceptable. In this study, four BGYF grains per 2.5 kg unground maize sample successfully indicated an aflatoxin contamination of >10 μg/kg (10 μg/kg being the maxium tolerable level proposed by the Common Market for Eastern and Southern Africa), with a 4.4% false negative rate. In this case, the amount of confirmatory analyses would be reduced by 63%, if the BGYF test was employed as a screening method. The screening technique therefore offers a practical tool for Malawi and possibly for the Sub-Saharan region. Source


Matumba L.,University of Malawi | Matumba L.,Chitedze Agricultural Research Station | Van Poucke C.,Ghent University | Biswick T.,University of Malawi | And 3 more authors.
Food Control | Year: 2014

A total of 9 traditional maize based opaque beers were randomly collected from tribal (chewa) rituals and commercial village brewers from Lilongwe and Dowa districts, Malawi in August 2012 for evaluation of mycotoxins using a multi-mycotoxin method based on liquid chromatography-tandem mass spectrometry. Samples were analyzed for aflatoxins B1 (AFB1), AFB2, AFG1, AFG2, fumonisin B1 (FB1), FB2, FB3, zearalenone, ochratoxin A, nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, neosolaniol, fusarenon-X diacetoxyscirpenol, HT-2 toxin, T-2 toxin, alternariol, alternariol methyl ether, and sterigmatocystin. All beer samples were positive for fumonisins with FB1. +. FB2 and FB1. +. FB2. +. FB3 content of 1745. ±. 1294. μg/kg (mean. ±. std. dev.) and 1898. ±. 1405. μg/kg respectively. With exception of one beer sample, all the beers also contained aflatoxins at a mean concentration of 90. ±. 95. μg/kg. Consumption of 1.0-6.0. L of the traditional beer from this study translates to daily FB1. +. FB2 exposure of 29-174. μg/kg body weight (bw)/day (i.e. >provisional maximum tolerable daily intake of 2. μg/kg bw/day set by the Joint FAO/WHO Expert Committee on Food Additives) and aflatoxin exposure of 1.5-9.0. μg/kg bw/day for a 60. kg adult. The study demonstrated that the consumption of the maize based traditional home-made beer in Malawi can significantly enhance aflatoxins and fumonisin dietary exposure among beer consumers. © 2013 Elsevier Ltd. Source


Sileshi G.W.,Chitedze Agricultural Research Station | Arshad M.A.,University of Alberta | Konate S.,University of Abobo Adjame | Nkunika P.O.Y.,University of Zambia
Journal of Vegetation Science | Year: 2010

Objectives: To (1) assess the strength of evidence for the role of termites in vegetation heterogeneity in African savannas, and (2) identify the mechanisms by which termites induce such heterogeneity. Location: African savannas. Methods: We conducted a review of the literature, a meta-analysis and qualitative systems analysis to identify mechanisms to explain the observed patterns. Results: The review provided evidence for termite-induced heterogeneity in floristic composition and vegetation patterning in savannas across Africa. Termites induced vegetation heterogeneity directly or indirectly through their nest-building and foraging activities, associated nutrient cycling and their interaction with mammalian herbivores and fire. The literature reviewed indicated that termite mounds essentially act as islands of fertility, which are responsible for ecosystem-level spatial heterogeneity in savannas. This was supported by the meta-analysis, which demonstrated that mounds of Ancistrotermes, Macrotermes, Odontotermes (family Macrotermitinae), Cubitermes (family Termitinae) and Trinervitermes (Nasutitermitinae) are significantly enriched in clay (75%), carbon (16%), total nitrogen (42%), calcium (232%), potassium (306%) and magnesium (154%) compared to the surrounding savanna soil. Conclusions: Termite activity is one of the major factors that induce vegetation patterning in African savannas. The implications of this are discussed and research questions for future studies and modelling efforts are indicated. © 2010 International Association for Vegetation Science. Source


Kamara A.Y.,International Institute Of Tropical Agriculture | Tefera H.,Chitedze Agricultural Research Station | Ewansiha S.U.,International Institute Of Tropical Agriculture | Ajeigbe H.A.,International Institute Of Tropical Agriculture | And 3 more authors.
Crop Science | Year: 2011

A field study was conducted to determine the rate of genetic improvement in grain and fodder yields and associated agronomic and physiological changes of determinate and semideterminate cowpea [Vigna unguiculata (L.) Walp.] genotypes developed in the Nigerian Sudan savannas in 1974 to 2004. Results showed that grain yield of determinate cowpea ranged from 796 kg ha -1 for cultivars released in the 1970s to 1485 kg ha -1 for cultivars released in the 2000s with a corresponding genetic gain of 2.93% per year. Mean grain yield of semideterminate cow-pea ranged from 638 to 1547 kg ha -1 with relative annual gain of 4.4%, suggesting that more progress was made in breeding semideterminate cowpea cultivars for high grain yield. Fodder yield of determinate cowpea ranged from 1493 kg ha -1 for culti-vars released in the 1970s to 2332 kg ha -1 for those released in 2000s, an average 1.74% genetic gain per year. For semideterminate cowpea, fodder yield increased from 1698 kg ha -1 for older cultivars to 2612 kg ha -1 for modern cultivars with relative annual gain of 2.15%. The general gain in fodder yield for both cowpea types indicated that selection for dual-purpose cowpea cultivars with increased fodder as well as grain yields has been successful. This study also revealed that genetic gains were made in the improvement of yield related traits such as pods per plant, 100-seed weight, total dry matter, and harvest index (HI) for both plant types. A remarkable progress has been made in increasing the total dry matter over the three decades period. This trait was significantly associated with grain yield (r = 0.60 for determinate cowpea and r = 0.53 for semidetermi-nate cowpea). Other traits that were significantly correlated with grain yield were fodder yield, number of pods per plant, and HI for determinate cowpea and fodder yield, HI, and 100-seed weight for semide-terminate cowpea. The strong relationship between grain and fodder yields showed the success made in selecting for dual-purpose cowpea cultivars. © Crop Science Society of America. Source

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