Agriculture and Soil Management in the Context of Sustainable Development in the Sudano-Sahelian Zone of Cameroon

The Sudanian-Sahelian zone of the Far-North Cameroon faces an extreme climate challenge resulting in increased vulnerability to erosion, soil degradation, and the effects of climate change, impacting soil fertility and agricultural yields. The objective of this study was to analyze agricultural practices, challenges related to climate change and soil degradation, as well as the solutions adopted by farmers to address these issues. To achieve this, 600 farmers from the six departments of the region were interviewed. The results highlight the significant impact of climatic conditions on soil health, agricultural activities, and food security. Farmers identified various indicators of soil degradation, including agricultural yields, bioindicator plants, plant growth, soil fauna, and root density. The main causes of soil degradation are associated with practices such as deforestation, intensive agriculture, the use of chemical fertilizers and pesticides, overgrazing, and the effects of climate change. The impacts of this degradation are multiple, including soil fertility loss, reduced agricultural yields, deforestation, reduced biodiversity, income loss, water resource pollution, and food insecurity. In response to these challenges, farmers have adopted sustainable soil management practices, including crop rotation, intercropping, fallowing, the use of organic fertilizers, and the adoption of conservation agriculture. To effectively address these challenges, concerted collaboration between farmers, civil society organizations, and government authorities is imperative to develop sustainable and effective solutions against soil degradation in the region.

Greywater Treatment by High Rate Algal Pond under Sahelian Conditions for Reuse in Irrigation

High Rate Algal Pond (HRAP) was constructed and operated using a mixer device to investigate its capability in treating greywater for reuse in gardening. Physico-chemical and microbiological parameters were monitored. With a hydraulic retention time of 7.5 days and a solid retention time of 20 days, the average removal efficiencies (ARE) were 69% and 62% for BOD5 and COD respectively. The ARE for , and were 23%, 52% and 43% respectively. The removal of suspended solids (SS) was unsatisfactory, which could be attributed to the low average algal settling efficiencies of 9.3% and 16.0% achieved after 30 and 60 minutes respectively. The ARE of fecal coliforms, Escherichia coli and enterococci were 2.65, 3.14 and 3.17 log units respectively. In view of the results, the HRAP technology could be adapted for greywater treatment in sahelian regions. However, further studies on the diversity of the algal species growing in the HRAP unit are necessary in order to increase the removal of SS. Hazards of a reuse of the effluents are discussed on the basis of the various qualitative parameters. The residual content of E. coli was varying from 4 CFU per 100 mL. Based on WHO guidelines for greywater reuse in irrigation, the effluents could be used for restricted irrigation (E. coli < 105 CFU per 100 mL). Furthermore, the reuse potential is discussed on the basis of FAO guidelines using SAR (3.03 to 4.11), electrical conductivity (482 to 4500 μS/cm) and pH values (6.45 to 8.6).

CHARACTERISTICS,ORIGIN AND EVOLUTION AGES OF AEOLIAN SAND IN THE SAHELIAN REGION OF MALI

The Sahelian region of Mali is one of the areas seriously affected by sandy desertitication in the world.Widely distributed aeolian sand lays a material basis for the development of sandy desertification. Aeolian sand in the region is dominated by fine sand, followed by very fine sand. Sand materials contained in various sand dunes are different in grain size to a certain extent and the mineral compositions of dune sand are dondnated by stable and extreme stable minerals, with high stability and maturity. Aeolian sand in the region mainly comes from the reachvation of ancient sand dunes, the transportation of recent runing water and the sand supply of dry lakes and arroyos. Since the Pliocene this region has experienced four major evolution periods of aelian sand, namely from the Pliocene to the early Quaternary, last glacial period, the Holocene and present.

Composition and Diversity of Soil Bacterial Communities along an Environmental Gradient in the Sudano-Sahelian Region of Senegal

The soils of the semi-arid Sudano-Sahelian region of West Africa have been identified as being highly vulnerable to soil degradation with impacts on their capacity to provide goods and services in which soil microorganisms participate. Unfortunately, soil microbial diversity from this semi-arid region with high rainfall variability remains largely unexplored. The aim of the present study was to characterize the diversity and composition of the soil bacterial communities and to identify factors involved in their spatial distribution along an environmental gradient in Senegal. Samples were collected from non-anthropogenic sites across four pedoclimatic zones. Bacterial communities were characterized using next-generation sequencing and soil physico-chemical parameters were determined. Our results showed that Firmicutes, Actinobacteria, Proteobacteria, Chloroflexi, Gemmatimonadetes, Acidobacteria, and Verrucomicrobia phyla were predominant in the soils of the region. Bacterial α-diversity was stable along the environmental gradient whereas β-diversity highlighted significant changes in the composition of the soil bacterial community. Changes were driven by shifts in the relative abundance of OTUs belonging mainly to the genus Bacillus, Conexibacter, Kaistobacter, Solirubrobacter, Ktedonobacter, Sphingomonas, Microvirga, Rubrobacter and Pelobacter. Soil properties like pH, soil moisture and clay content were the environmental parameters identified as drivers of the composition of the bacterial communities in the semi-arid Sudano-Sahelian region of Senegal (West Africa).

Morphological and Biometric Diversity of Colletotrichum capsici Isolates, Causal Agent of Cowpea Brown Blotch Disease (Vigna unguiculata (L.) Walp) in the Sudano-Sahelian Zone of Cameroon

Cowpea [Vigna unguiculata (L.) Walp] is an important legume in the midst of about 170 species of its genus because it is an important source of protein and other essential nutrients for humans and animals. Its production faces many constraints such as the cowpea brown blotch disease caused by Colletotrichum capsici which contributes in wet conditions of the field to losses ranging from 42% to 100%. This study was conducted to identify Colletotrichum capsici isolates responsible for cowpea brown blotch disease and to determine their diversity in the Sudano-Sahelian zone of Cameroon. Identification and isolation were made from cowpea organ samples on the Potato Dextrose Agar (PDA) medium and, morphological and biometric characteristics such as: the colony color, the mycelium shape, the abundance of acervules, the presence or absence of saltations, the mycelial growth rate, the conidia length and width were used to assess the diversity. The results obtained indicate that 55 Colletotrichum capsici isolates have been identified in the Sudano-Sahelian zone of Cameroon. Statistical analysis showed that there is a significant difference between isolates. Isolates showed multiple colony colours and were brown coloured as presented by 36.36% of isolates, compact mycelium is found in 56.36% of isolates, 56.36% of isolates have abundant acervulis, and saltations were absent in 45.45% of C. capsici isolates. The mycelial growth rate is between 6.69 mm/d and 12.33 mm/d. The principal component analysis (PCA) made indicated that there are differences between the observed and measured characteristics. The Hierarchical Ascending Classification (HAC) was done and 10 morphotypes of C. capsici in the Sudano-Sahelian zone were identified.

中国北方农牧交错带与非洲萨哈尔地带全新世环境变迁的比较研究

中国北方农牧交错带和非洲萨哈尔带均为处在季风尾闾带的干旱向半湿润气候过渡的地带。通过对比分析 ,发现两个地带自然地理环境及其全新世以来的环境演变等具有很大程度的相似性 ;自全新世以来 ,两个地带均出现过几乎同步的 8个千年尺度的冷暖、干湿旋回 ;在近百年的干湿变化方面都有 10～ 2 0a变化周期 ;在少雨期和多雨期的转变过程中非洲萨哈尔带较中国北方农牧交错带提前 5a以上。这一超前信息的存在 ,为中国北方农牧交错带的气候预测提供了一个重要的前兆因素。

Inventory, Geographical Distribution of <i>Caryedon</i>Species in Burkina Faso, and Evaluation of Their Impact on Stored Groundnut

To understand the mechanism of infestation of stored groundnut in farming areas, studies on the inventory and geographical distribution of Caryedon species were carried out in the tree savannah and in producers’ storage structures. The incidence of C. serratus in stored groundnut was evaluated. Inventory and geographical distribution of insects belonging to Caryedon genus was achieved through a sampling in the savannah and producers’ granaries. The inventory and geographical distribution of insects was made throughout Burkina Faso whereas the evaluation of the perforations of groundnut pods was made in the western zone of the country. The results of the inventory showed the presence of two species belonging to Caryedon genus which are C. serratus and C. crampelii. These species are found on the agro-ecological zones of the country. The survival and maintenance of Caryedon species genus are ensured by the presence of plants belonging to various families such as Caesalpiniceae and Mimosaceae. The evaluation of the losses caused by C. serratus in producer’s stored groundnut revealed that the pods perforation rate varied according to the locality. In?Toussiana, the rate of perforated pods ranged from 53.72% to 100% in five months while in?Karangasso Sembla, for the same conservation time, the rate was in the range from 2.8% to 35%. However it is C. serratus which is responsible for the losses observed in the stored groundnut. Indeed, in the western area of Burkina Faso where more than 25% of the production is realized, 70% of groundnut stocked without treatment is destroyed by this insect after only four months of storage.

Allometric models for estimating aboveground biomass and carbon in Faidherbia albida and Prosopis africana under agroforestry parklands in drylands of Niger

This study developed allometric models to estimate aboveground biomass and carbon of Prosopis africana and Faidherbia albida. The destructive method was used with a sample of 20 trees per species for the two parkland sites. Linear regression with log transformation was used to model aboveground biomass according to dendrometric parameters. Error analysis, including mean absolute percentage of error(MAPE) and root mean square of error(RMSE), was used to select and validate the models for both species. Model 1(biomass according to tree diameter) for P. africana and F. albida were considered more representative. The statistical parameters of these models were R2 = 0.99, MAPE 0.98% and RMSE1.75% for P. africana, and R2 = 0.99, MAPE 1.19%,RMSE 2.37% for F. albida. The average rate of carbon sequestered was significantly different for the two species(P ≤ 0.05). The total amount sequestered per tree averaged0.17 × 10-3 Mg for P. africana and 0.25 × 10-3 Mg for F. albida. These results could be used to develop policies that would lead to the sustainable management of these resources in the dry parklands of Niger.

Compressed Bricks Made of Makabaye and PitoaréClay: Implementation and Production

In a strong commitment to economic valorisation that began a decade and relevant contribution to the problems of housing and creation of small jobs response, the Cameroonian government has invested heavily in promoting use of local materials through the creation of MIPROMALO (Mission for Promotion of local Materials) in 1991 (economic crisis), and through the signing of government circular from the Prime Minister, thus placing its development policies in prior to any development strategy more distant prospect. It was then that housing through development of local building materials becomes one of major policy priorities of Cameroonian’s government. However, there is a low valuation thereof despite availability of local materials and political will expressed in Circular No. 002/CAB/PM of 12 March 2007 on the use of local materials in construction of public buildings. In this study, we analyse the contribution that can play promotion of local materials in construction in the Sahel zone which for a harmonious sustainable development. Specifically, it’s to highlight the added value of using local materials, propose strategies for implementation and production of compressed bricks. This scientific work has therefore a double interest, scientific and technological industrial view and contributes to the development, promotion of local materials and the development of soil and/or basement areas. We arrived after analysis of our data to the conclusion that valuation of clay materials from Maroua’s town was a factor for economic growth and sustainable development. This inventory allows us to implement and produce prototypes suitable compressed bricks, shapes of housing in Sahel zone. However, physical and geotechnical tests on materials clay (raw materials for production of bricks), allow us to better assess characteristics of clay before production of bricks. Well after we submit our bricks to various mechanical and technological tests to assess their ability to withstand loads in extreme temperature conditions of Sahel zone.

Breast Morphometry in Senegalese Women:Study on a Sample of 118 Subjects

Nowadays, women are more and more resorting to breast surgery for the purposes of isolated esthetics or within the framework of a mammectomy for tumor with its cohort of psychological problems post mutilation often requiring reconstruction. In context of breast cancer increase in Senegal, we have carried out breast morphology in female subjects of the Sahelian type in order to contribute to the development of a morphological database for reconstruction, reduction or breast augmentation. It was a prospective study on 118 female subjects received at Cancer Institute for screening. They were divided into two groups (age ≤ 40 years and age?> 40 years). Subjects’?morphometric variables were collected in anatomical position and correlated with age, parity, obesity and genital activity using. Fifty six subjects (47.5%) were over 40 years of age. There were 40 multiparous (33.9%). Fifteen subjects (12.7%) and six subjects (5%) were obese and morbidly obese, respectively. Subjects in genital activity were 34 (29%). The overall average size of the areola was 4.3 ± 1.5 cm. The nipple was low located with an average of 7.2 ± 3.5 cm. The diameters mentioned above increased significantly with age and body mass index, for p-values ?0.05, with the exception of the vertical diameter. Breast diameters were greater in postmenopausal women. Morphometry of Sahelian-type women’s breast is strongly influenced by socio-demographic data, hence the need to take it into account during reconstruction, reduction or breast augmentation surgeries in Senegal.