scholarly journals The contibutions of soil properties to cassava yield parameters in Sub-Saharan Africa

Agro-Science ◽  
2007 ◽  
Vol 6 (1) ◽  
Author(s):  
C L Asadu ◽  
F I Nweke ◽  
A G Dixen
Keyword(s):  
Soil Properties ◽  
Sub Saharan Africa ◽  
Yield Parameters ◽  
Sub Saharan

Food Crop Yields and Soil Properties under Population Pressure in Sub-Saharan Africa: the Case of Cassava in Southeast Nigeria

1997 ◽  
Vol 26 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Charles L. A. Asadu ◽  
Anselm A. Enete
Keyword(s):  
Soil Properties ◽  
Crop Yields ◽  
Exchange Capacity ◽  
Parent Material ◽  
Sub Saharan Africa ◽  
Population Pressure ◽  
Southeastern Nigeria ◽  
Cassava Root ◽  
Sub Saharan ◽  
Major Factors

Cassava root yields in three villages in southeastern Nigeria with marked differences in population pressure were related to soil properties using various models. The soils of the low population village, being formed from a different parent material, were more fertile than those of the medium and high population villages and cassava root yields were significantly higher in this village. The specific soil properties which appeared to promote cassava yields included pH and contents of Mn, silt and sand. Absolute values of exchangeable Mg, Ca, acidity and effective cation exchange capacity, although not significantly correlated with root yield, were also most favourable in the low population village. Thus inherent differences in soil properties rather than population pressure may be the major factors contributing to variations in cassava root yields in these villages.

scholarly journals Soil carbon persistence linked to mineralogy across sub-Saharan Africa

2021 ◽  
Author(s):  
Sophie F. von Fromm ◽  
Alison M. Hoyt ◽  
Benjamin M. Butler ◽  
Asmeret Asefaw Berhe ◽  
Sebastian Doetterl ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Carbon ◽  
Aridity Index ◽  
Soil Survey ◽  
Sub Saharan Africa ◽  
Mean Annual Temperature ◽  
Soil Mineralogy ◽  
Diverse Range ◽  
Model Calculations ◽  
Sub Saharan

<p>Recent compilations of global soil radiocarbon data suggest that current Earth System Models underestimate the mean age of soil carbon (C). The discrepancy between data-derived estimates and model calculations might be due to an inadequate representation of processes that control C persistence in soils – especially in understudied regions.</p><p>Here, we investigate the relationships between soil mineralogy, soil properties, climate and radiocarbon (Δ<sup>14</sup>C) in soils sampled as part of a comprehensive soil survey (AfSIS) for sub-Saharan Africa. A total of 510 samples were analyzed, comprised of soils collected from two depths (0–20 cm and 20–50 cm) at 30 sites in 14 countries. To determine soil mineralogy, we analyzed X-ray powder diffraction (XRPD) data, which provides a precise and detailed mineralogical signature of each soil sample. The studied soil profiles vary greatly in their mineralogy, reflecting a diverse range of parent materials and soil forming factors.</p><p>The median soil C age is 182 years in the topsoils and 563 years in the subsoils, corresponding to a total Δ<sup>14</sup>C value range of -432 to 95 ‰. In general, Δ<sup>14</sup>C values decrease (older mean C ages) with increasing clay particle size fractions. This corresponds to an increase in short range-order minerals expressed as oxalate-extractable aluminum and iron (Al<sub>ox</sub> and Fe<sub>ox</sub>). Separately, mineralogically defined variables – derived from the XRPD data using principal component analysis – are found to correlate strongly with a range of soil properties (pH, weathering status, exchangeable calcium, Al<sub>ox</sub> and Fe<sub>ox</sub>, and soil texture) and climatic variables (aridity index and mean annual temperature). This provides a holistic assessment of the processes that have formed each soil along with the properties that it currently exhibits. Our analyses with random forests show that these XRPD-derived mineralogical variables alone can explain up to 30% of the variation in Δ<sup>14</sup>C across sub-Saharan Africa. They also allow the identification of specific minerals that contribute to this variation and how they are linked to the C mean age of the soil. In conclusion, our results suggest that soil mineral data can help to better understand C persistence in subtropical and tropical soils.</p>

RTS,S/AS01, a vaccine targeting pre-erythrocytic stages of Plasmodium falciparum

2017 ◽  
Vol 1 (6) ◽  
pp. 533-537
Author(s):  
Lorenz von Seidlein ◽  
Borimas Hanboonkunupakarn ◽  
Podjanee Jittmala ◽  
Sasithon Pukrittayakamee
Keyword(s):  
Protective Efficacy ◽  
Age Groups ◽  
Sub Saharan Africa ◽  
Phase Iii ◽  
European Medicines Agency ◽  
Older Children ◽  
Pivotal Phase ◽  
Malaria Epidemiology ◽  
Maximum Benefit ◽  
Sub Saharan

RTS,S/AS01 is the most advanced vaccine to prevent malaria. It is safe and moderately effective. A large pivotal phase III trial in over 15 000 young children in sub-Saharan Africa completed in 2014 showed that the vaccine could protect around one-third of children (aged 5–17 months) and one-fourth of infants (aged 6–12 weeks) from uncomplicated falciparum malaria. The European Medicines Agency approved licensing and programmatic roll-out of the RTSS vaccine in malaria endemic countries in sub-Saharan Africa. WHO is planning further studies in a large Malaria Vaccine Implementation Programme, in more than 400 000 young African children. With the changing malaria epidemiology in Africa resulting in older children at risk, alternative modes of employment are under evaluation, for example the use of RTS,S/AS01 in older children as part of seasonal malaria prophylaxis. Another strategy is combining mass drug administrations with mass vaccine campaigns for all age groups in regional malaria elimination campaigns. A phase II trial is ongoing to evaluate the safety and immunogenicity of the RTSS in combination with antimalarial drugs in Thailand. Such novel approaches aim to extract the maximum benefit from the well-documented, short-lasting protective efficacy of RTS,S/AS01.

Mortality and Society in Sub-Saharan Africa

1993 ◽  
Vol 47 (3) ◽  
pp. 555-556
Author(s):  
Lado Ruzicka
Keyword(s):  
Sub Saharan Africa ◽  
Sub Saharan

Adolescent Suicidality as Seen in Rural Northeastern Uganda

Crisis ◽  
2011 ◽  
Vol 32 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Eugene Kinyanda ◽  
Ruth Kizza ◽  
Jonathan Levin ◽  
Sheila Ndyanabangi ◽  
Catherine Abbo
Keyword(s):  
Low Socioeconomic Status ◽  
Sub Saharan Africa ◽  
Psychosocial Risk ◽  
Psychiatric Nurses ◽  
Health Concern ◽  
Cross Sectional ◽  
Childhood Experiences ◽  
Low Socioeconomic ◽  
Dsm Iv ◽  
Sub Saharan

Background: Suicidal behavior in adolescence is a public health concern and has serious consequences for adolescents and their families. There is, however, a paucity of data on this subject from sub-Saharan Africa, hence the need for this study. Aims: A cross-sectional multistage survey to investigate adolescent suicidality among other things was undertaken in rural northeastern Uganda. Methods: A structured protocol administered by trained psychiatric nurses collected information on sociodemographics, mental disorders (DSM-IV criteria), and psychological and psychosocial risk factors for children aged 3–19 years (N = 1492). For the purposes of this paper, an analysis of a subsample of adolescents (aged 10–19 years; n = 897) was undertaken. Results: Lifetime suicidality in this study was 6.1% (95% CI, 4.6%–7.9%). Conclusions: Factors significantly associated with suicidality included mental disorder, the ecological factor district of residence, factors suggestive of low socioeconomic status, and disadvantaged childhood experiences.

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