Phosphorus Uptake and Balance in a Soyabean-Maize Rotation in the Moist Savanna of West Africa

This study investigated the effect of maturity class on phosphorus (P) balance in a soyabean-maize rotation in the West African moist savanna.F our soyabean varieties of different maturity classes were grown with or without P fertilizer followed by a maize crop. Soyabean stover P content averaged 1.77 kg ha−1 compared with 5.13 kg ha−1 in the grain. The late soyabean variety TGx1670-1F accumulated a significantly higher P in the grain (6.56 kg ha−1), and stover (2.57 kg ha−1) than the others. While P harvest index averaged 79%, P application increased grain P by 63-81% and stover P by 100% or more. When either soyabean grain or grain+stover was exported, P balance was negative and was not statistically different for varieties when no P was applied. At 30 or 60 kg P ha−1, P balance was negative but significantly lower in TGx1670-1F compared with other varieties. In creasing P rate applied to soyabean significantly (p 0.01) increased maize grain P by 35-66% in the second year. When P was exported only in soyabean grain, cumulative P balances after maize grain harvest (with no P or 30 kg ha−1 applied previous year) were not significantly different for previous soyabean crops. At 60 kg ha−1, however, P balance in previous TGx1670-1F plot was significantly lower than for other varieties. A further export of soyabean stover reduced P balance. Significant residual P effect was observed emphasizing the need to focus P fertilizer application in the cropping system rather than on the single crop. Also with more P in soyabean grain, a reduction in the extent of P depletion will be achieved by returning soyabean stover to the field after threshing

Adoption of improved cowpea (Vigna unguiculata (L.) Walp) technologies in Ghana

The Ghana Grains Development Project has developed and disseminated improved cowpea production technologies to farmers in Ghana since 1985. These technologies were improved varieties, row planting, and the use of pre- and post-flowering insecticides. To assess the extent of adoption of these technologies by farmers, eight cowpea production districts were surveyed across four agro-ecological zones in 1995 in Ghana. A random sample of 313 cowpea farmers participated in the survey. Results indicated that 70 per cent used recommended pre-flowering insecticides, and 26 per cent adopted post-flowering insecticides across the ecological zones. The highest adoption rate for improved varieties was observed in the Forest Zone (97 %). The adoption of row planting was highest in the Forest Zone (100 %), followed by the Guinea Savanna Zone (92 %), and lowest in the Coastal Savanna Zone (58 %). Most farmers agreed that by adopting improved production technologies, their yields and overall production increased, and they made more profit from cowpea cultivation.The whole family participates in various activities associated with cowpea production. However, men do strenuous work like land preparation, weeding and spraying of insecticides, while women and children participate in less strenuous work such as planting, harvesting and threshing. Le Project de Développement des Grains du Ghana a developpé et disséminé les technologies de la production de dolique amélioré aux cultivateurs au Ghana depuis 1985. Ces technologies étaient les variétés améliorées, la culture en lignes et usage d'insecticides avant et après la floraison. Pour évaluer le degré d'adoption de ces technologies par les cultivateurs, un sondage a été entrepris en 1995 en 8 districts de production de dolique à travers quatre zones agro-écologique au Ghana. Un échantillon pris au hasard de 313 cultivateurs de dolique participaient au sondage. Les résultats indiquaient que 70% utilisaient les insecticides d'avant floraison recommandés et 26% adoptaient les insecticides d'après floraison à travers les zones écologiques. La proportion d'adoption la plus élevée pour les variétés améliorées était observée dans la zone forestière (97 %). L'adoption de la culture en lignes est la plus élevée dans la zone forestière (100 %) et suivi par la zone savane-guinéenne (92 %) et la plus faible dans la zone savane-littorale (58 %). La plupart de cultivateurs étaient du même avis que par l'adoption des technologies de production améliorée, leur rendements et la production globale augmentaient, et ils avaient tiré plus de bénéfice de la production de dolique. Toute la famille participent aux activités différentes liées à la production de dolique. Cependant le travail ardu tel que la préparation de terre, le désherbage et la pulvérisation d'insecticide sont faites par les hommes alors que les femmes et les enfants participent aux travaux moins ardus tels que la plantation, la moisson et la battage. Ghana Journal of Agricultural Science Vol. 39 (1) 2006: pp. 25-3

Household hunger, poverty, and childcare in 5 states of Nigeria and their impacts on nutritional outcomes in preschool children

Open Access Article; Published online: 04 May 2021This article presents findings from baseline surveys in 5 states of Nigeria to assess the nutritional outcomes on target groups on attaining the UN Sustainable Development Goal 2. The augmented regression technique was applied to analyze data from a sample of 1642 households with at least 1 child under the age of 5 years (U5) and their mothers or caregivers out of a total of 2500 households that were drawn from the 250 enumeration areas of the Nigeria Bureau of Statistics in the 5 states. The results support the growing evidence base that poverty and household hunger are pervasive. The incidence of poverty highlights inequalities among states. The combination of poverty and hunger was mirrored in the damning extent to which all forms of malnutrition coexisted in children U5, particularly during the second year of infancy and among poor households. Evidence from this study points to poor dietary quality of complementary food rather than other childcare practices as majorly responsible for child malnutrition. Child wellness was positively affected by maternal health-seeking behavior but negatively by the poverty probability index of the household. Notably, maternal health-seeking behavior played a more relevant role in child wellness than mothers’ educational attainment

Buffer layer-assisted growth of Ge nanoclusters on Si

In the buffer layer-assisted growth method, a condensed inert gas layer of xenon, with low-surface free energy, is used as a buffer to prevent direct interactions of deposited atoms with substrates. Because of␣an unusually wide applicability, the buffer layer-assisted growth method has provided a unique avenue for creation of nanostructures that are otherwise impossible to grow, and thus offered unprecedented opportunities for fundamental and applied research in nanoscale science and technology. In this article, we review recent progress in the application of the buffer layer-assisted growth method to the fabrication of Ge nanoclusters on Si substrates. In particular, we emphasize the novel configurations of the obtained Ge nanoclusters, which are characterized by the absence of a wetting layer, quasi-zero dimensionality with tunable sizes, and high cluster density in comparison with Ge nanoclusters that are formed with standard Stranski-Krastanov growth methods. The optical emission behaviors are discussed in correlation with the morphological properties

Ge quantum dot arrays grown by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface: nucleation, morphology and CMOS compatibility

Issues of morphology, nucleation and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (<600 deg C) and high (>600 deg. C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts---pyramids and wedges---are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.Comment: 30 pages, 11 figure

System Performance Projections for TPV Energy Conversion

TPV technology has advanced rapidly in the last five years, with diode conversion efficiency approaching &gt;30%, and filter efficiency of {approx}80%. These achievements have enabled repeatable testing of 20% efficient small systems, demonstrating the potential of TPV energy conversion. Near term technology gains support a 25% efficient technology demonstration in the two year timeframe. However, testing of full size systems, which includes efficiency degradation mechanisms, such as: nonuniform diode illumination, diode and filter variability, temperature non-uniformities, conduction/convection losses, and lifetime reliability processes needs to be performed. A preliminary analysis of these differential effects has been completed, and indicates a near term integrated system efficiency of {approx}15% is possible using current technology, with long term growth to 18-20%. This report addresses the system performance issues

Capturing Single Cell Genomes of Active Polysaccharide Degraders: An Unexpected Contribution of Verrucomicrobia

Microbial hydrolysis of polysaccharides is critical to ecosystem functioning and is of great interest in diverse biotechnological applications, such as biofuel production and bioremediation. Here we demonstrate the use of a new, efficient approach to recover genomes of active polysaccharide degraders from natural, complex microbial assemblages, using a combination of fluorescently labeled substrates, fluorescence-activated cell sorting, and single cell genomics. We employed this approach to analyze freshwater and coastal bacterioplankton for degraders of laminarin and xylan, two of the most abundant storage and structural polysaccharides in nature. Our results suggest that a few phylotypes of Verrucomicrobia make a considerable contribution to polysaccharide degradation, although they constituted only a minor fraction of the total microbial community. Genomic sequencing of five cells, representing the most predominant, polysaccharide-active Verrucomicrobia phylotype, revealed significant enrichment in genes encoding a wide spectrum of glycoside hydrolases, sulfatases, peptidases, carbohydrate lyases and esterases, confirming that these organisms were well equipped for the hydrolysis of diverse polysaccharides. Remarkably, this enrichment was on average higher than in the sequenced representatives of Bacteroidetes, which are frequently regarded as highly efficient biopolymer degraders. These findings shed light on the ecological roles of uncultured Verrucomicrobia and suggest specific taxa as promising bioprospecting targets. The employed method offers a powerful tool to rapidly identify and recover discrete genomes of active players in polysaccharide degradation, without the need for cultivation