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Differing effects of grass and polythene mulches on sweet potato productivity in derived savannah agro-ecology
24-30.Views:338Sweet potato as a food crop that is grown for both its tuberous roots and vegetative parts, the latter of which also serves as animal feed. Its production in the savanna regions can be limited by high evaporative demand, especially where soils with low water retentivity are involved. This work studied the effects of various locally available polythene as mulch materials for sweet potato growth in derived savanna agro-ecology. An experiment was thus conducted at Nsukka, a derived savannah in southeastern Nigeria, with orange fleshed variety of sweet potato. Treatments were polythene mulches of contrasting colours (black, white, red and blue polyethylene), including also organic mulch (dry grasses) as reference and a no-mulch control. The experiment was executed in two successive cropping seasons, and the data averaged and analysed. Agronomic and weed incidence data collection was done fortnightly from 2nd to 10th week of planting. The results showed that the polythene mulches (especially the black one) were better in the control of weeds. Furthermore, the sweet potato yields were affected significantly (p < 0.05) by mulching on the total number of tubers for each plant with grass-mulched plots showing the highest value (36) and transparent polyethylene-mulched plots the lowest (19). Also, total weight of tubers per plant at harvest differed (p < 0.05), with grass-mulched plots showing the highest value (2.39 kg), followed by the control (no mulching) plots (1.62 kg), then the coloured polyethylene mulched plots with the red polyethylene-mulched plots as the lowest (0.64 kg). This study recommends the use of organic mulch or no mulching in sweet potato production in this agro-ecological zone as they produced the best yields.
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Selenium enriched vegetables as biofortification alternative for alleviating micronutrient malnutrition
75-81.Views:810There is a very difficult equation for malnutrition and over-consumption. That means malnutrition even of vitamins and/or minerals (Ca, Cu, Fe, I, Mg, Se and Zn, vitamin A) affects more than two billion people worldwide, largely due to low concentrations or poor bioavailability of the nutrients in the diet. In some developed countries in contrast, over-consumption, particularly of over-refined cerealbased foods, has contributed to the development of an epidemic of metabolic diseases. So, producing nutritious and safe foods sufficiently and sustainably is important target at the same time challenge of modern agriculture. In the past, great efforts have focused only on increasing crop yields, but enhancing the concentrations of mineral micronutrients has become an urgent task. The main daily food source is the staple crops specially in developing countries of the world, i.e., wheat, rice, cassava, beans, sweet potato or maize. These kind of plants are often deficient in some of mineral elements. Thus, the increasing of bioavailable concentration of micronutrients in edible crop tissues (via biofortification) has become a promising strategy in modern agriculture, providing more nutritious foods, to more people, with the use of fewer lands. Biofortification of these trace elements can be achieved application with agronomic process such as soil or foliar fertilization or crop breeding even conventional technic and/or genetic engineering. This review highlight progress to date and identify challenges faced in delivering biofortified vegetable crops as well as the agronomic approaches and tools to improve crop yield and micronutrient content of food crops.
