Variations in soil fertility under cotton crops in the Bénoué cotton-growing area in Northern Cameroon

The status of soils under cotton crops must be compared before and after a sufficiently long cropping period in order to detect variations that have occurred. Continuous monitoring of plots in research stations to determine such patterns is, however, long and costly. To overcome this problem, a study was carried out in 2004 on plots that had been monitored previously. Scientists, technicians and farmers who participated in the first assessment were also involved in the present study, so the plots could be accurately located. The second assessment was conducted using the same analytical techniques as those described in the first assessment. A database was compiled with data from 58 plots on ferruginous soils in the Bénoué cotton-growing area, with the interval between two assessments ranging from 4 to 21 years. The results presented here concern 27 plots. The study revealed that: (i) the soil organic matter and available P contents had barely declined, (ii) the soil CEC had sharply decreased along with the N, K, Ca and Mg soil mineral contents, and (iii) this decline in mineral reserves paralleled the mineral budget of the crops. These hypotheses should be confirmed by processing the remaining collected data, but it was found that the characteristics of these especially fragile soils decreased. These results were readily and cost-effectively obtained. The geographical coordinates of the fields in which soil samples were collected were unfortunately not determined, and the soil analysis results were not adequately stored. This calls for the construction of databases to pool raw research results that are accessible to everyone. Research would thus fulfil its role of producing and providing public access to collected information. (Résumé d'auteur

Regulation of Microfinance Institutions in Developing countries: an incentives theory approach

We analyze the optimal policy of regulation of microfinance institutions in developing countries, where investment funds are insured by the government and customer deposits. We used a mixed model, combining adverse selection and moral hazard to characterize a class of optimal incentive schemes applied in presence of government funds and in non-government funded. We also analyse the effects of prudential regulation of deposits on the profitability of MFI and social welfare, and we compare prudential and non-prudential regulation. The incentive scheme that we propose can be regarded as a "smart subsidy" mechanism that contributes to the economic and social development

Intensification of maize cultivation: impacts of climate, soils fertility and prices in Northern Cameroon

Soils degradation is the factor that most affects the profitability of crop management on maize cultivation in Northern Cameroon and reduces the interest of their intensification. It is also affected by severe weather conditions but mainly by low valuation of agricultural products. Maize cultivation intensification is only possible with the help of a seasonal credit system to acquire inputs. The use of casual hired labor and an increase in the purchase price of corn are other conditions that will favor its implementation. (Résumé d'auteur

Effect of processing conditions on cyanide content and colour of cassava flours from West Africa

The evolution of cyanide content and colour were monitored during the processing of lafu, traditional flour and improved flour from five cassava cultivars from Benin. In addition, the total phenol, polyphenoloxidase (PPO), peroxydase (POD) and linamarase activities were assessed. The processing of cassava in lafu and improved flour proved superior for producing safe and white non-fermented and fermented cassava flours with total cyanide mean values of 16.6 and 11.4 mg HCN/kg, db and DE values of 9.2 and 12.1, respectively. Detoxification appeared to be only linked to processing, in particular to the size reduction level of cassava roots, regardless of the initial cyanide level and the linamarase activity of the fresh roots. Cassava flour yellowness was closely linked to the phenol content (r = 0.95) that decreased after steeping and pressing. The PPO and POD activities did not appear to be linked to flour discoloration. (Résumé d'auteur

Forest co-management policy and transformational adaptation in Burkina Faso

In most regions of West Africa, livelihoods depend on goods and services from savannah ecosystems, in interplay with agricultural and livestock production systems. Economic, ecological, social and political changes represent challenges for the governance of the commons. In the international development agendas, adaptive co-management appears as an emergent and promising strategy in complex and multi scale, overlapping, governance mechanisms among socio-ecological systems. In Burkina Faso, under state control, forest policies have been introduced since the 1980s' that give more rights to communities to access and collectively manage forest resources in bounded areas. In two villages involved in this devolution process, we conducted vulnerability assessment surveys and focus group discussions. We analyse how vulnerability and adaptive capacity of people, belonging to different social groups, using common resources, evolve under the implementation of this co management system promoted by the state on behalf of sustainable development. We also analyse how the management norms shape people's collective action and adaptive capacity and how they reflect their ordinary priorities. We discuss the pertinence of this resource management system to both incremental and transformational adaptation to climate change. Our results show that comanagement applied without reinforced rights and leadership of the most vulnerable, including a radical change in behavioural and institutional patterns, tends to maintain existing power relationships, renders powerless groups vulnerable and inhibits institutional adaptive transformation to climate change. (Résumé d'auteur

Introduction des désherbants chimiques dans la zone cotonnière du Cameroun : diagnostic d'une innovation en pleine expansion

International audienceDurant les campagnes agricoles 1999 et 2000, une étude sur le semis direct avec désherbage chimique a été réalisée au sud du bassin cotonnier du Nord-Cameroun. L'objectif était de faire un diagnostic sur cette innovation, afin de savoir comment elle se diffuse, les principales contraintes et envisager les voies d'amélioration. Cette synthèse est le résultat d'une série d'enquêtes et d'observations dans 55 exploitations agricoles, réparties dans différents terroirs de la zone d'étude. Les paramètres pris en compte sont, les superficies cultivées en semis direct et en labour, le taux d'équipement, les types des herbicides et les différentes doses utilisées par les paysans. Cette innovation représente 40% à 70% des superficies cultivées en cotonniers selon les régions. L'adoption et le succès de cette technique auprès des agriculteurs, sont liés à une politique des prix d'achat attractifs et au passage dans le domaine public des herbicides totaux (paraquat et glyphosate), mais aussi au fait que cette technique permet la mise en place rapide et précoce des cultures. En outre, l'utilisation des herbicides procure une économie en temps de travail (18 à 24 heures/ha) et en investissement. Après avoir relevé les difficultés liées à la maîtrise des mauvaises herbes, l'étude permet d'orienter les voies d'amélioration de ce système de culture vers des itinéraires techniques sans travail de sol et avec couverture végétale. (Résumé d'auteur

Coarse and uniform embeddings between Orlicz sequence spaces

We give an almost complete description of the coarse and uniform embeddability between Orlicz sequence spaces. We show that the embeddability between two Orlicz sequence spaces is in most cases determined only by the values of their upper Matuszewska-Orlicz indices. On the other hand, we present examples which show that sometimes the embeddability is not determined by the values of these indices.Comment: 12 pages. This is the final version. To appear in Mediterr. J. Mat