Department of Environment and Natural Resources

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    Iodine Agronomic Biofortification of Cabbage (Brassica oleracea var. capitata) and Cowpea (Vigna unguiculata L.) Is Effective under Farmer Field Conditions
    (Agronomy MDPI, 2019-11-23) Ojok, Joe; Omara, Peter; Opolot, Emmanuel; Odongo, Walter; Olum, Solomon; Gijs, Du Laing; Gellynck, Xavier; De Steur, Hans; Ongeng, Duncan
    Abstract: Iodine (I) is an essential micronutrient, which plays a critical role in human metabolism. However, its concentration is known to be low in most soils, making it deficient in crops. With most I agronomic biofortification studies conducted under controlled environments, limited information currently exists on this approach of enriching I deficient crops under farmer field conditions. Two-year field experiments were conducted in 2017 and 2018 to examine efficacy of cowpea and cabbage in the uptake of foliar applied potassium iodide (KI) and potassium iodate (KIO3), each with 0, 5, 10, and 15 kg I ha−1 under farmer field conditions. Results indicate that KI was 34% more efficient than KIO3. Iodine concentration increased with application rate. In cabbage, the lowest I concentration (8.2 mg kg−1 ) was registered at 5 kg I ha−1 with KIO3 while the highest was 109.1 mg kg−1 at 15 kg I ha−1 with KI. Cowpea registered the lowest I concentration of 531.5 mg kg−1 at 5 kg I ha−1 with KIO3 while the highest (5854.2 mg kg−1 ) was registered at 15 kg I ha−1 with KI. Therefore, cowpea and cabbage can be effectively biofortified through foliar application of both KI and KIO3 under farmer field conditions.
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    The successional pathway of the tree community and how it shapes the fruit-feeding butterfly community in an Afrotropical forest
    (Cambridge University, 2016-10-29) Valtonen, A; Malinga, G.M; Nyafwono, M; Nyeko, P.; Owiny, A.; & Roininen, H.
    The relative importance of different bottom-up-mediated effects in shaping insect communities in tropical secondaryforestsarepoorlyunderstood.Here,weexploretherolesofvegetationstructure,forestage,localtopography (valley vs. hill top) and soil variables in predicting fruit-feeding butterfly and tree community composition, and tree community composition in predicting fruit-feeding butterfly community composition, in different-aged naturally regeneratingandprimaryforestsofKibaleNationalPark,Uganda.Wealsoexaminewhichvariablesarebestpredictors of fruit-feeding butterfly species richness or diversity. Butterflies (88 species) were sampled with a banana-baited trap and trees (98 taxa) with a 40 × 20-m sampling plot at 80 sampling sites. The environmental variables explained 31% of the variation in the tree community composition, the best predictors being local topography, forest age and cover of Acanthuspubescens (a shrub possibly arresting succession). The fruit-feeding butterfly community composition was better predicted by tree community composition (explaining 10% of the variation) rather than vegetation structure, local topography or soil factors. Environmental variables and tree species richness (or diversity) were poor predictors of butterfly species richness (or diversity). Our results emphasize the importance of tree community to recovery of herbivorous insect communities in tropical secondary forests.