Biomass production and management practices in mixed crop-livestock systems in the west African Sahel: Opportunities and constraints

The Sahel is characterized by a marked inter-annual climate variability and has experienced a number of food security crises following the severe droughts during the 1970s and 1980s. Due to recent challenges such as rapid population growth, climate change, environmental concerns and market changes which cause major impacts to their production systems, the sahelian people have been shifting and adapting their production systems and the way they live to cope with uncertainties. The objective of the present report is to review the various biomass production and management issues in the mixed crop-livestock systems in West African Sahel. An elaborated literature survey of peer reviewed papers mostly, was conducted. The studies were based on the Sahel scale research, more specifically research that had been published on the West African Sahel, including studies published between 1990s and 2016. Results show that many factors have contributed to the changes, among which, rainfall variability, population growth, human induced-activities, land tenure systems and the effects of globalization. Various biomass production and management practices are employed in West African Sahel for both on-farm and off-farm biomass improvements. Some of the best practices are mulching, soil and water conservation techniques, composting, farmer managed natural regeneration, agroforestry, etc. These practices have overall contributed to increase agricultural productivity, ecosystem services provisioning and have sometime deepened the difference between men and women, rich and poor, young and old people. Most of the constraints associated with large adoption of the best practices in the Sahel are land tenure systems, the huge gap between inputs and output investment costs but, the climate conventions are offering new opportunities that will ultimately contribute to positive changes. This will be possible only when land tenure systems in the region are reinforced, institutional linkages are strengthened, and new information systems are used to inform farmers on climate issues and new agricultural practices

Multilevel decomposition approach to the preliminary sizing of a transport aircraft wing

A multilevel/multidisciplinary optimization scheme for sizing an aircraft wing structure is described. A methodology using nonlinear programming in application to a very large engineering problem is presented. This capability is due to the decomposition approach. Over 1300 design variables are considered for this nonlinear optimization task. In addition, a mathematical link is established coupling the detail of structural sizing to the overall system performance objective, such as fuel consumption. The scheme is implemented as a three level system analyzing aircraft mission performance at the top level, the total aircraft structure as the middle level, and individual stiffened wing skin cover panels at the bottom level. Numerical show effectiveness of the method and its good convergence characteristics

Study of thin film large area photovoltaic solar energy converter Second quarterly report, 1 Jan. - 31 Mar. 1963

Thin film large area photovoltaic solar energy converter - cadmium sulfide films producted by vacuum evaparation techniqu

Improving small ruminant productivity and livelihoods through feed and health interventions: Evidence from northern Ghana

United States Agency for International Developmen

The Assessment of Forms and Bioavailability of Copper, Chromium, and Cadmium in Soils of Automobile Workshops using Sequential Extraction Procedure

The quantification the exact dimension of heavy metals pollution in soils requires more data than the total contents of metals in soils. The determination of different fractions (speciation) is necessary to understand the mobility and bio-availability of the metals in soils. This paper presents results of speciation of copper (Cu), chromium (Cr), and cadmium (Cd) in soils of ten automobile workshops in Sapele, Nigeria. Composite soils samples were taken from depth 0 – 60cm, and geochemical forms and total concentrations of the metals (Cu, Cr & Cd) in soils were determined by sequential extraction procedures and atomic absorption spectrometry. The total concentrations range of: 39.10 – 129.80mg/kgCu, 11.55 – 40.10mg/kgCr, and 3.15 – 6.28mg/kgCd obtained for the soils in the vicinities of the automobile workshops were distinctly higher than that of the control indicating enrichment of these metals in these soils. Speciation revealed that 20 – 33% Cu, 19 – 27% Cr and 25 – 45% Cd, were potentially mobile and bio-available. Keywords: sequential extraction, bio-availability, heavy metals, soils, automobile workshop