Potential use of clay from Burkina Faso as filler in rubber production

raw clay materials deposit in Burkina Faso have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis to evaluate their potentialities to be used in rubber compounds production as filler. The samples are composed principally by aolinite, illite and quartz. The rubber compounds have been done in open two-roll mill at room temperature and tested for cure characteristic (ts5, tc90), ineralogical composition by XRD, microstructure by SEM and mechanical properties (Elongation at break, Tear strength, tensile strength, hardness shore A and modulus). The cure characteristics of the rubber compounds formulated with the sample are feeble than those made with commercial kaolin (control). The mechanical properties are in general, except the longation at break, for the sample lowest than those of control. However the different values obtained with the sample are not far to those obtained with commercial kaolin. The different samples can then be used as filler in rubber production after a pre-treatment to reduce the impurities.Keywords: Raw clay materials, rubber, rheology

Crop residue management in relation to sustainable land use : a case study in Burkina Faso

IntroductionTraditional agricultural production systems in Sub-Saharan Africa were based on transfer of nutrients by grazing animals from rangeland to cropland, combined with fallowing. These systems are under increasing pressure as a result of rapid population increase. In most of the semi-arid and sub-humid zones, the area of rangeland, required to maintain cropland productivity, is not available anymore. The associated continuous decline in soil productivity induces risks of food shortage and irreversible soil degradation, and every effort should be made to avoid further deterioration of the resource base. Integration of crops and livestock and the associated intensified nutrient cycling are often advocated as desirable developments towards sustainable land use. Performance of these integrated systems hinges on the management of crop residues and manure, which represent the main source of organic matter and nutrients for animal and soil.The objective of the present study was to analyse the consequences of alternative management techniques of crop residues, from a sustainable crop-livestock farming perspective in the North Soudanian zone of Burkina Faso. The specific objectives were: (1) To establish response curves describing the effect of (varying degrees of) selective consumption of crop residues (as single feeds and in various combinations) on animal production; (2) to evaluate the effect of alternative systems of feeding crop residues on labour requirements and household income; (3) to evaluate the effect of alternative systems of feeding residues on crop production and on organic matter, nitrogen and phosphorus balances at farm level; (4) to determine the trade-offs among various objectives associated with alternative crop residue management techniques.The approachThe potential contribution of crop residues to ruminant feeding in the four agro-ecological zones distinguished in Burkina Faso was estimated, applying the Java Program developed at the Animal Production Systems Group of Wageningen University (Chapter 2). The number of animals that can be fed and their production were estimated on the basis of availability and quality (digestibility and N content) of crop residues (cereal stovers and legume haulms).Feeding trials were carried out with sheep to determine the relationships between the quantities of crop residues offered on the one hand, and intake and digestibility of ingested material on the other hand. In Chapter 3, the effect of selective consumption on intake and digestibility of sorghum, cowpea and groundnut residues is described. Two additional feeding trials were conducted as a basis for optimising the use of cowpea and groundnut haulms as supplement to sorghum stover (Chapter 4). The models used for analysis of the data allow description of the combined effects of animal selectivity for the better fractions of cereal stover, and of supplementation, on intake and digestibility of ingested material. Results of the feeding trials complemented by literature data served as the basis to derive iso-production curves. Based on the isoquant concept, least-cost rations were derived for a range of combinations of cereal stovers and supplements.The possibilities for optimal utilisation of crop residue at farm level was analysed using a linear programming technique. To quantify the relevant household resources, constraints and objectives, farm surveys were conducted (Chapter 5). The above-mentioned iso-production curves served as the basis for quantification of the technical coefficients for animal feeding activities, while for crop activities various models from the literature were applied to the region under consideration. A Multiple Goal Linear Programming (MGLP) model (referred to as HOREB, Household level Optimal crop REsidue allocation in Burkina Faso) was developed to determine the effect of various crop residue management techniques on farm productivity, economics and sustainability, in terms of balanced organic matter, nitrogen and phosphorus budgets (Chapters 6 and 7). The main results are discussed in Chapter 8, with special attention for the contribution of crop residues to sustainable land use in Sub-Saharan Africa.Contribution of crop residues to ruminant feeding at regional levelOn the basis of current crop production, 54 and 98 % of the current ruminant population can potentially be maintained during the dry season in the Sub-Sahelian and North-Soudanian zones, respectively. There might even be scope for increasing the contribution of crop residues to animal production in these areas, by increasing production of legume haulms and allowing selective use of stover leaves.It may also be profitable to take advantage of the capacity of animals to use feeds selectively by excess feeding. This requires, however, collection techniques and conservation structures that minimise the reduction in nutritive value of the scarce highest quality residues (legume haulms). The objective of rearing animals, either maximisation of animal production or maintaining the maximum number of animals, determines the most suitable feeding techniques. Maximising animal production is associated with inclusion of smaller quantities of cereal stovers in the ration and with a smaller number of animals kept. Maintaining the maximum number of animals allows the use of more cereal stovers and results in higher manure availability for arable fields, and so may contribute to maintaining cropland productivity.Optimising crop residue use at animal levelResults of the feeding trials show that unsupplemented sorghum stover can hardly be used for animal production, due to its low intake and digestibility, and its low protein content. Even maintenance can only be reached if selective consumption of leaves is allowed; In our trials, sheep reached the maintenance level only when 87 g OM kg -0.75d -1was offered, of which only 53 % was eaten. Offering cowpea and groundnut haulms, maintenance can be achieved with 36 and 39 g OM kg -0.75d -1, respectively. These results illustrate, that when coarse, low quality forages are fed alone, selection is not a waste, but a prerequisite for animal production and even for maintaining animals. Excess feeding of sorghum stover (allowing selective consumption of leaves), significantly reduced the quantity of supplement (cowpea and groundnut haulms) needed to reach a desired level of intake of digestible organic matter (IDOM). Up to 54 g OM kg -0.75d -1of groundnut haulms was needed for 1.4 times maintenance (33.6 g DOM kg -0.75d -1) when animals ingested 90 % of the sorghum stover, but only 29 g OM kg -0.75d -1was needed, when animals were allowed to eat only 50 % of the sorghum stover offered.Optimising crop residue use at farm levelThe results of farm surveys indicate that availability of a donkey cart for transport allowed storage of significantly more high quality crop residues (cowpea haulms). The stored residues served as animal feed (100 % for legume haulms and 70 % for cereal stovers), the remainder being used as building material, source of fuel for cooking, etc. Crop residues remaining in the fields are commonly grazed and only the non-edible parts serve as soil amendment. Factors such as relationships between farmers and herdsmen, location of fields, herd composition and production system, and available means of transportation determine the quantities of crop residues collected.On a farm (6.2 ha available land) with 210 md available labour per month, where crop residues are not collected for stall feeding in the dry season and no capital is available to buy fertiliser, a maximum of 3.2 t staple food can be produced in normal (average rainfall) years. When the household does collect crop residues for sheep stall feeding and aims at maximum gross margin, attainable staple production hardly changes, when no external inputs are used. The household could produce 4.5 t staple, when maximising total gross margin under balanced OM and nutrient budgets, provided sufficient working capital to buy external inputs is available. Model results suggest that reduction of the current crop area by 0.5 to 1.2 ha (depending on the restrictions imposed on nutrients budgets) is necessary to allow integration of sheep stall feeding, because of the required labour for residues collection. Integration of sheep stall feeding could then contribute to restriction of the expansion of the crop area without compromising households food security.Availability of labour for crop residue collection and storage is the major limiting factor for the integration of crops and stall feeding of sheep. Labour availability dictates, in combination with the objectives of animal keeping, the selection among the different feeding techniques. Chopping, requiring substantial investment in labour, is selected when the farmer aims at maximising availability of manure, security or savings, for which a maximum number of animals is fed at maintenance. Treatment with urea requires, in addition to chopping, working capital to buy urea. This option is hardly ever selected because of the combined limitations of labour, capital and low remuneration. At the current urea price and labour availability conditions, excess feeding is the best method of feeding in all scenarios.Maximising crop gross margin is always associated with soil mining; 20-27 % of calculated farm gross margin originates from soil mining, if soil nutrients and organic matter are valued at inorganic fertiliser and stover prices, respectively. From 200- 344 kg OM, 15-21 kg N and 1.5-1.8 kg P per ha are lost annually from the system when animals are not stall fed (extensive feeding system). When crop residues are collected for stall feeding of sheep and the farmer aims at maximum total gross margin, annual losses are 175-192 kg OM, 12-15 kg N and 1.1-1.2 kg P. The results of these analyses clearly illustrate that intensive management of crop residues in integrated crop-livestock farming systems cannot maintain soil nutrient status. Nutrients from external sources are necessary, either in the form of concentrate or fertiliser. Moreover, maximum gross margin per manday of labour invested in sheep feeding activities is 0.20 kF, which is much lower than the actual labour wages in the area. Hence, if off-farm employment is available, stall-feeding of sheep is not an economically attractive alternative. Economic profitability can be improved if capital availability allows utilisation of concentrate, i.e. 0.28 kF extra gross margin can be attained per kF invested in cotton seed cake. Potentially, attainable gross margin from sheep feeding is 182 kF per household, when crop residues would be optimally collected (80 % of the cereal stovers and 86 % of the legume haulms produced).ConclusionsIntegration of crops and livestock is often considered as a step towards sustainable agricultural production, because of the associated intensified organic matter and nutrients cycling through intensive crop residue management. The main advantage of the integration of livestock and crops is the added value derived from crop residues (especially those of legumes) in terms of animal products and income. Intensive management of crop residues in integrated crop-livestock farming appears a means of guaranteeing subsistence in an environment characterised by growing competition for organic matter and nutrients between animals and soil. Sustainable production, at regional level, can only be triggered by external inputs. However, the current price ratios of fertiliser and grains are hardly conducive to fertiliser utilisation. The prospects for sustainable crop-livestock production are intimately linked to the price of external inputs and to the low availability of working capital. Investment in concentrate is remunerative, but lack of cash is a serious constraint for their acquisition. Improved credit facilities for farmers may stimulate intensification of livestock production and thereby increase nutrient availability for cropland, and hence sustainable land use practices.</p

Aspects épidémiologiques et étiologiques des affections pulmonaires d’origine parasitaire et fongique en milieu hospitalier à Ouagadougou (Burkina Faso)

Dans le souci de déterminer l’aspect épidémiologique et étiologique des affections pulmonaires d’origines parasitaire et fongique, une étude prospective transversale a été réalisée en milieu hospitalier à Ouagadougou de novembre 2012 en mai 2013, sur 103 patients suspectés avoir la maladie. Les examens parasitologiques, mycologiques et immunologiques ont été effectués selon les indications des prescripteurs, sur des prélèvements du liquide de lavage broncho-alvéolaire, du liquide pleural, des expectorations et du sang. A l’issue de ces examens, 59,2% des patients confirmés porteurs de parasites et/ou de mycètes dans leur appareil pulmonaire avec une prédominance des cultivateurs (26,2%) ont été détectés. Les hommes étaient les plus touchés avec un sex-ratio de 1,9. Parmi les antécédents médicaux, il y a eu une fréquence élevée des sujets à sérologie VIH positive. Trois parasites et 71 souches de champignons ont été isolés dont 4 types de coinfections fongiques. Ces données de bases montrent que les parasites et les champignons provoquent une pathologie pulmonaire non spécifique sur le plan clinique, radiologique et endoscopique. Le contexte épidémiologique et biologique permet d’orienter le diagnostic. La confirmation est apportée par la mise en évidence directe ou par des arguments indirects sérologiques. Ce qui permet d’obtenir une guérison par un traitement adapté au germe en cause.Mots clés : Affection pulmonaire, parasites, champignons, Burkina Faso

Restoration of Degraded Lands in West Africa Sahel: Review of experiences in Burkina Faso and Niger

This is a comprehensive literature review of land restoration activities in West Africa Sahel. Water constraints and the inherent soil poverty are the major factors that limit crop yields and productivity of cropping systems in West Africa Sahel (WAS). Livestock is not well integrated with agricultural activities and crop residues are usually exported from the farm for household needs and animal feeding. In traditional systems, soil fertility maintenance was based on a relatively long fallow period (10-15 years) followed by a short cropping period of 3 to 5 years. But the increased population pressure has resulted in significant changes of the traditional bushfallow system. Lands are now continuously cultivated for long period with low external inputs, leading to soil fertility decline over time (Bationo and Mokwunye 1991; Bekunda et al. 2010). In addition to biophysical aspects, a wide range of socio-economic factors such as the low financial capacities of poor farmers to invest in agricultural inputs, high pressure on ecological resources for food, fodder or energy, also add to the stress on the systems. Failure by the smallholder farmers to intensify agricultural production in a manner that maintains soil productivity is the main cause of land degradation, particularly in the fragile ecosystems of WAS. Land degradation is defined as a process that leads to the reduction of land productivity for useful purposes, and is typically a result of soil, wind, or water erosion; soil salinization; waterlogging; chemical deterioration; or any combination of these factors (Adeel 2003). Land degradation is a global problem, particularly in the dry areas, home to a large population of poor farmers, where land degradation and water scarcity are major threats to food security. The impacts of land degradation are severe on both human society and ecosystems. Desertification is often wrongly attributed solely to droughts, but it is the deadly combination of continued land abuse during periods of deficient rainfall that results in unproductive land, and ultimately desertification (UNESCO 2003). Combating desertification by rehabilitating degraded lands can be done successfully, using existing, often traditional techniques. Land restoration involves restoring the fertility of degraded lands. The social syndrome where diminishing availability of lands, inherent low fertility, continuous soil erosion, and continuous nutrient removal without replenishment, results in a spiraling downfall in productive capacity and a diminished resilience of the soil system to provide a suitable medium for crop growth needs to be addressed. Smallholder farmers are at the center of both soil fertility decline and restoration process. Their decisions to manage, to utilize technologies and to improve or restore soil fertility are guided by the socioeconomic conditions and the overall benefits that will accrue from production (Sanginga and Woomer, 2009; Bekunda et al. 2010). A sustainable management of lands under cultivation and the restoration of degraded lands could be achieved by affordable strategic management innovations; taking into account the socioeconomic conditions of farmers. While individual technologies can contribute; a more integrated systems that combines technologies, crops, and trees such as the agroforestry systems could better contribute for sustainable management of natural resources. Many efforts have been invested to developing strategies and approaches for both sustainable management of natural resources and restoration of degraded lands in WAS. In some cases, farmer communities have developed sound, sustainable approaches to land rehabilitation and management but there is insufficient information on successful restoration in the context of WAS, particular with regards to policy, institutions and socioeconomic conditions under which specific approaches could be adapted and applied successfully (Bunning 2003). The main objective of this review was to investigate the main experiences of regenerating degraded landscapes (RDL) in Niger. Going through the documentation, we found many similarities in experiences across the two countries of Niger and Burkina. Some interesting experiences were found in Burkina, Niger or at the same time in the two countries. We finally decided to extend the review to the two countries as a representative zone of the WAS. The critical issue in taking restoration to scale is that ecological, economic and institutional context varies at fine scales. The main goal of this review is to identify the specificities and the context of the most efficient experiences of RDL that could be widely scaled in the WAS

Median and average as tools for measuring, electing and ranking: new prospects

Impossibility theorems expose inconsistencies and paradoxes related to voting systems. Recently, Michel Balinski and Rida Laraki proposed a new voting theory called Majority Judgment which tries to circumvent this limitation. In Majority Judgment, voters are invited to evaluate candidates in terms taken in a well-known common language. The winner is then the one that obtains the highest median. Since the Majority Judgment proposal was made, authors have detected insufficiencies with this new voting system. This article aims at reducing these insufficiencies by proposing a voting system to decide between the median-based voting and the mean-based one. It proposes, moreover, a new tie-breaking method computing intermedian ranks mean

New prospects in social choice theory: median and average as tools for measuring, electing and ranking

The goal of this paper is to show that neither mean-based voting systems nor median-based ones can fulfill requirements of an ideal democracy. We then work out an original voting function obtained by hydrizing Borda Majority Count (mean-based) and Majority Judgment (median-based). The so-called “Mean-Median Compromise Method” slices between mean and average values. It proposes, moreover, a new tiebreaking method computing intermedian grades mean

LA RAGE INFANTILE A PORTE D’ENTREE CEPHALIQUE (À propos de deux cas)

Après une morsure suspecte par un chien errant, la brièveté de la période d’incubation peut être préjudiciable aux victimes. Nous rapportons deux cas de rage furieuse à porte d’entrée céphalique dont la brièveté de la période d’incubation n’a pas permis de conduire à terme la prophylaxie antirabique. Le premier est un enfant de sept ans mordu à l’oreille gauche par un chien errant et le second est un adolescent de 14 ans mordu à la pommette droite. Le premier avait une blessure de catégorie II et le second avait une blessure de catégorie III. Tous avaient commencé la vaccination antirabique après la morsure suspecte mais la brièveté de la période d’incubation n’avait permis de terminer la série vaccinale avant que la maladie ne se déclare. Il nous semble utile d’associer la sérothérapie antirabique à la vaccination, en cas de morsure céphalique de catégorie II ou III. Les agents de santé devraient être conséquemment formés pour une prise en charge efficiente des cas de morsure par un chien errant

Participatory forest management in Burkina Faso: Members’ perception of performance

This study examines variations in the performance of participatory forest management programs among four forest management groups (FMGs) in southern Burkina Faso, and assesses the factors that influence their members’ perceptions of performance through a household survey of 216 members. Variations in performance scores among the FMGs were analyzed through multivariate analysis of variance while multinomial regression analysis was used to identify factors that influence their perception of the performance. The results reveal significant differences in performance scores among FMGs. Members of some FMGs perceived that the participatory forest management program enabled them to get benefits from the sale of fuelwood while performance scores in the forest conservation and decision-making processes is generally poor. The score for economic performance of FMGs in turn was related to better access to roads and markets. Group size tended to enhance economic performance via its strong influence on annual fuelwood harvest, while the resource base appeared to be inconsequential. Members of the forest management groups perceived that large group size and group heterogeneity, particularly in terms of ethnicity, as well as knowledge and awareness of problems related to the forest environment have no influence on the performance of their respective groups. For rural communities to have a favorable disposition toward sustainable forest management, differences in member understanding of collective actions and their impact before and during the implementation of participatory forest management programs should be considered

Effects of burning on soil macrofauna in a savanna-woodland under different experimental fuel load treatments

In West African savanna-woodland, the use of prescribed burning as a management tool has ecological implications for the soil biota. Yet, the effects of fire on soil inhabiting organisms are poorly understood. The aim of this study was to examine the responses of soil macro-invertebrates to early fires in a Sudanian savanna-woodland on a set of experimental plots subject to different fuel load treatments. The abundance of major macro-invertebrate taxa and functional groups, and taxon richness were quantified in soil cores collected from three different soil layers before and immediately after burning. The results indicated that, overall, there was substantial spatial and temporal variation in the composition of macro-invertebrate assemblages. The immediate effects of fire were to reduce total invertebrate numbers and numbers of many invertebrate groups dramatically. This is probably due to the fact that many of the surface-dwelling macrofauna perished as a result of less favorable microclimate due to fire, diminished resources, or migrate to safer environments. Fuel load treatment did not affect the community taxonomic richness or abundance of the soil-dwelling fauna. Furthermore, annual changes in community composition were more pronounced at the burnt site than in the control. This could be related to the inter-annual difference in precipitation pattern recorded during the two-year study period at our site. Since soil macrofauna population declines in fire-disturbed areas, increasing fire prevalence may jeopardize the long-term conservation of fire sensitive macrofauna groups. Special fire management attention is therefore recommended with due consideration to the type of burning and fuel properties to avoid the detrimental effects of intense fire affecting the resilience of savanna soil macrofauna species

New prospects in social choice theory: median and average as tools for measuring, electing and ranking

The goal of this paper is to show that neither mean-based voting systems nor median-based ones can fulfill requirements of an ideal democracy. We then work out an original voting function obtained by hydrizing Borda Majority Count (mean-based) and Majority Judgment (median-based). The so-called “Mean-Median Compromise Method” slices between mean and average values. It proposes, moreover, a new tiebreaking method computing intermedian grades mean