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Aims: To improve the nutritional values of carrot in the Great North Cameroon by using natural fertilizing. Study Design: A 11x2x2 factorial design with 11 origins of carrot roots (fertilizing) (T0, T+, P10, P15, Py10, Py15, F1, F1+P10, F1+P15, F1+Py10 and F1+Py15), 02 harvest areas (Maroua and Ngaoundere (Cameroon)) and 02 harvest years (2019 and 2020). Place and Duration of Study: Laboratory of Biodiversity and Sustainable Development, University of Ngaoundere Cameroon, September 2019 and September 2020. Methodology: Nutrient parameters of carrot roots (moisture, vitamin C, carotenoids, fiber, carbohydrates and ash of carrot roots contents) were assessed according to standard methods. Results: Globally, carrot nutritional values varied significantly (p

Aims: Amendment of ferralitic soils of Ngaoundere (Cameroon) by rock materials, so-called petrofertilizer, can be a promising solution to improve their fertility and thus enhance crop yield. Study Design: In the present study, the influence of pyroclastic powder on the growth of the common bean (Phaseolus vulgaris L.) was assessed. Place and Duration of Study: Department of Biological Sciences. The sowing was done on June 13, 2017 until 2 septembre. Methodology: An experimental design with four (04) different treatments was implemented: 0 g per pot (0% of pyroclastic: the control), 150 g per pot (10% of pyroclastic: P10 Treatment), 300 g per pot (20% of pyroclastic: P20 Treatment) and 450 g per pot (30% of pyroclastic: P30 Treatment). The pyroclastic powder was applied at three different (03) stages: sowing, germination, and flowering stage. All the treatments were irrigated with 250 ml of water once every 3 days during the growing stage. Results: Growth parameters, seed yield, and seeds nutritional values were measured. Results revealed that seeds yield from the treated pot using 30% of pyroclastic powder is 4.2 times greater than that of the control. Globally, pyroclastic powder improved the nutritional values of common bean seeds compared to the Control. Fertilizing the soils at the sowing stage significantly (p

Aims: Moringa oleifera is a species with multivariate uses. Despite its socio-economic importance in the northern part of Cameroon, it remains undervalued. Understanding its contribution to the fight against climate change requires precise quantification of its biomass. However, there is a lack of site-specific allometric equations for estimating this biomass. The development of site-specific allometric equations of M.oleifera is therefore imperative to facilitate this effort. Study Design: To achieve this objective, a sample of fourteen trees of M.oleifera was taken in from the two areas and divided into diameter classes between 5 and 13 cm. Place and Duration of Study: Sample: Agroecological zones of High guinean savannahs and Sudano-sahelian zone of Cameroon between April and July 2021. Methodology: The diameter at breast height of these trees and their height were measured. After tree cutting, biomass of compartments of leaves, branches, trunks and roots were determined after drying and weighing. Various allometric equations between biomasses and two parameters of the tree (the diameter and the height) were tested. The adjusted coefficient of determination (R2adj), the residual standard error (RSE) and the Akaike Information Criteria were used for choosing the best models. Results: The different analyses showed that diameter at breast height (DBH) is the variable that offers the best correlation for global above-ground (AGB) and below-ground (BGB) biomass in contrast to the other compartments. Thus, the best models for predicting total above-ground biomass of M. oleifera are -3.653-0.250lnD+5.119lnH (Sudano-Sahelian), -3.916 + 2.982lnD (High guinean Savannahs), -2.340 + 2.117lnD (Global) and finally for roots -6.426 + 2.182lnD. Conclusion: These mathematical models could help in estimating the biomass of Moringa oleifera in agroforestry systems under the ecological conditions of Cameroon.

The present study aimed to evaluate the effect of the combination of various natural fertilisers on growth and seed yield of the soybean plants. Field experimentations were carried out during two cropping seasons (2018 and 2019). A randomized complete block experimental design with 11 treatments (F1: 30 g of poultry litter, F2: 60 g of poultry litter, MP: 10 g of mycorrhizae + 10 g of vivianite powder, MF1: 10 g of mycorrhizae + 30 g of poultry litter, MF2: 10 g of mycorrhizae + 60 g of poultry litter, PF1: 10 g of vivianite powder + 30 g of poultry litter, PF2: 10 g of vivianite powder + 60 g of poultry litter, MPF1: 10 g of mycorhizae + 10 g of vivianite powder + 30 g of poultry litter, MPF2: 10 g of mycorrhizae + 10 g of vivianite powder + 60 g of poultry litter, T+: chemical fertiliser, T–: unfertilised plants) and three replications were used. The growth parameters and seed yield were evaluated. The results showed that the growth and seed yield of soybean varied depending on the fertiliser and the cropping season. Plants that have received the MPF2 treatment exhibited significantly (p ˂ 0.05) the highest values of the studied parameters (plants height, foliar production, plants dry biomass, seed yield). The MPF2 treatment increased the seed yield of soybean by 20.08% and 184.76% compared to T+ and T– treatments, respectively. The supply of the following combination, 10 g of mycorrhizae + 10 g of vivianite powder + 60 g of poultry litter was found to be very promising in improving the soybean plant growth and therefore, can be used as an alternative to replacing the mineral fertilisers usually employed for the cultivation of this crop.

This work aims at determining the impact of soils' chemical properties on the dynamics of biodiversity in the Benoue National Park (BNP) of Cameroon and its peripheries (surrounding hunting concessions N ° 1, 4, 5 and 7). Nine, out of the sixteen soil units encountered in the BNP were studied, because of their accessibility. On each of these nine soil units studied, three elementary plots were materialized for the collection of soil samples and for the study of vegetation dynamics. The chemical parameters were evaluated according to appropriate methods and the dynamics of the vegetation was obtained by carrying out a floristic inventory. Heterogeneity was observed in the chemical parameters of the different soil units. Soil units S5 and S6 are the most damaged regarding their low organic matter content (0.95 ± 0.78%) and (1.02 ± 0.33%), their carbon (5.53 ± 4.54 g.kg-1) and (5.91 ± 1.93 g.kg-1) and nitrogen (1.20 ± 0.45 g.kg-1) and (1.89 ± 0.41 g.kg-1) contents and a very low C/N ratio (4.72 ± 3.96) and (3.29 ± 1.37) respectively. These soils also have a low floristic abundance S5 (22 ± 0.53 individuals) and S6 (8 ± 1.86 individuals) unlike S4 which has good chemical properties, according to its OM (5.60 ± 0.83 %) and carbon (32.49 ± 4.79 g.kg-1) content, and C/N ratio (22.38 ± 6.84). Consequently, its floristic abundance (75 ± 1.37 individuals) and diversity (18.42 %) are considerable. These results show that the degree of chemical degradation varies according to soils. Elsewhere chemical properties of the soil influence the dynamics and sustainability of the biodiversity.

Experiments in pots were conducted in order to establish appropriate technical route for regeneration of Afzelia africana, which becomes rare because of overexploitation in the Northern Cameroon. Study was conducted within campus of the University of Ngaoundere (Cameroon) from December 2017 to September 2018. A randomised experimental design with 04 treatments (control: unfertilized plant (T), compost derived from 100% cattle manure (CBV), compost derived from 100% poultry litter (CFP) and mixture 50% compost derived cattle manure with compost derived 50% poultry litter (MCBVFP)) was used. There were 45 plants per treatment. Seedling emergence rate and growth parameters (plant height, number of leaves per plant, diameter of stem at collar and total dry biomass of plant) were assessed, and 30 plants were sampled. Seedling emergence rates from treated pots by CBV, CFP and MCBVFP were 2.19, 1.81 and 1.31 respectively fold higher than that from unfertilized pots. There was a significant (p˂0.05) difference between compost qualities used relative to the growth parameters. CBV, CFP and MCBVFP encreased the total dry biomass of plants at 62.40%, 47.81%, 29.93% respectively compared to T. These results suggest that the origin and the quality of composting substrate was important not only for seedling emergence, but also for the growth of A. africana. We recommend the compost derived from 100% cattle manure for the regeneration of A. africana in the Nortern Cameroon.

Aims: Baillonella toxisperma P. (moabi) is a woody which belongs to Sapotaceae family. It is endemic to the forests of Congo Basin, and therefore to Cameroonian forests. In Cameroon, B. toxiperma undergoes anthropogenic pressure which may lead to its complete disappearance. In this respect, the establishment of an appropriate technical route for regeneration of this species, which becomes rare because of overexploitation, is a necessity. This study aimed to improve the regeneration of moabi while contributing to sustainable agriculture. Study Design: A random device design with 5 treatments (control, compost derived sugar cane processing waste, bagasse, molasses and bagasse-molasses mixture) was used. Place and Duration of Study: Under Bimodal Forest climate in the Central Cameroon region, between September, 2018 and April 2019. Methodology: The breaking of moabi seeds dormancy, physico-chemical properties of soil and produced compost, and growth parameters (plant height, foliar production, diameter of stem, and dry biomass of plant) were evaluated to determine the development of the seedlings. Results: Moabi seeds stored cold at 4°C for 48 hours before sowing germinated better. Compost significantly (p˂0.001) increased moabi plants growth compared to bagasse, molasses, bagasse-molasses mixture. Dry biomass of treated moabi plants by compost, bagasse, bagasse-molasses mixture and molasses were 1.80; 1.13; 1.78; 1.40 fold greater than those of unfertilized plants respectively. Conclusion: The use of sugar cane compounds works as a double benefit because in addition to using compounds previously discarded, we are adding potent fertilizers that act strongly on moabi growth.

Ricinus communis L. (castor bean) is an oilseed plant with multiple socio-economic benefits. It grows wild in Cameroon. The study aimed at determining main uses, describing, evaluating the carbon stock as well as carbon credits and geolocalizing castor bean accessions from Adamawa Cameroon. The location of various sites for ethnobotanical survey was identified by random sampling techniques which consist in randomly selecting the various locations, overall sample consists of 1440 peoples; the respondents were questioned individually using a questionnaire form. Results showed that castor bean is used to treat several diseases; seeds oil is consumed and plants present margico-religious powers. Four local castor bean accessions (Vina, Martap, Nyambaka and Bélel) were identified. Overall, there was a significant difference (p < 0.05) between castor bean accessions identified with respect to the physical characteristics of vegetative organs and seeds. Plants of Bélel accession were tallest (302.96 ± 44.36 cm) while the smallest plants height (148.63 ± 19.05 cm) were from Vina accession. Vina accession was the most widespread while Nyambaka and Bélel accessions were the least widespread in the study areas. This information will be useful in the implantation program of castor bean as alternative crop of the Cameroonian agriculture. © 2020 International Formulae Group. All rights reserved. Keywords: Ricinus communis L., ethnobotanical survey, vegetative organs, carbon stock, geolocalizing, Adamawa-Cameroon

The present work aims to show the biodiversity of traditional vegetables consumed by the people of the Nyong and Kelle division by an inventory. Traditional vegetables are those vegetables which originate from a locality or imported from another area, but are consumed by the people of the locality for many years (between twenty five and thirty) years. The consumption habit is transmitted from generation to generation. These vegetables become the heritage of the people consuming them. Some traditional vegetables are been abandoned nowadays in a way that if nothing is done they will disappear and this will lead to the loss of the food identity of this people. A systematic survey was carried out to identify the traditional vegetables found in the markets and crop farms in ten sub divisions of the Nyong and kelle division. In all 25traditional vegetables were recorded and fell under 15 botanical families according to the Linear Angiosperm Phylogeny Group III classification. According to parts of vegetables consumed 76% leafy, 12% fruit, 4%seed, 4% stem and 4% root vegetables were recorded .76% of the vegetables was cultivated and 14%was not cultivated. Some vegetables were used in folk medicine by the people to heal certain illnesses. The abandoned vegetables have to be encouraged for sustainable development and for the preservation of the food identity of the people of the Nyong and kelle division.

This study describes the diversity of arbuscular mycorrhizal fungi (AMF) that enter into association with castor bean growth wild in Subsaharan Africa. Three sites of castor bean stands were selected in each of the three Subdivisions (Ngaoundere I, Ngaoundere II and Nyambaka) of the Vina Division in Adamawa Cameroon. Soil samples and roots were taken from each castor bean rhizosphere. All samples from one site were mixed into a composite sample. Leek was used as trap plant. Mycorrhizal parameters, spores density and specific richness were determined following to the standard methods. After spore extraction, species identification was obtained through the informations provided by the International Vesicular Mycorrhizal fungi collection. Results indicate that Cameroonian castor bean accession was found to be symbiotic with AMF under Sudano-Guinean climate of Adamawa Cameroon. The morphological and structural characterization enabled the description of six AMF species, belonging to three genera: Glomus fasciculatum, Glomus sp1, Glomus sp2, Scutellospora calospora, Scutellospora purpurasens, Entrophospora infrequens. These findings open opportunities for domestication and application of AMF for a sustainable castor bean productivity.

This study describes endomycorrhiza that enter into association with Gossypium hirsitum L. (cotton) grown in North Cameroon. During the study, twenty seven (27) soil samples were collected from three Divisions of the North Cameroon (Benoue, Mayo-Rey, Mayo-Louti). In each Division, nine (09) composite soils were sampled, thus 03 per locality (village), corresponding to sampling sites. Cotton seeds were grown in field for 04 months. Mycorrhizal parameters, spores density and specific richness were determined following to the appropriate methods. After spore extraction, species description and characterization were obtained through the informations provided by the International Vesicular Mycorrhizal fungi collection (INVAM): http://invam.caf.wv.edu/fungi/taxonomy/species ID.htm. Results indicate that mycorrhizal parameters varied depending on sampling sites significantly (p˂0.05). Mayo-Louti (286.22 ± 11.47 spores/100 g of soil) and Benoue (273.77 ± 83.28 spores/100 g of soil) had higher spores densities than Mayo-Rey (209.55 ± 40.01 spores/100 g of soil). The morphological and structural characterization enabled the description of five endomycorrhizal species, belonging to four genera: Glomus constrictum, Glomus manihotis, Acaulospora kentinensis, Entrophospora infrequens, Rhizophagus intraradices. . Glomus is the only genus found in all sampling sites. These findings open opportunities for domestication and application of endomycorrhiza for a sustainable field productivity of cotton in the North Cameroon.Read Complete Article at ijSciences: V92020012257 AND DOI: http://dx.doi.org/10.18483/ijSci.2257

Thermal buckling of new model of functionally graded (FG) sandwich beams is presented in this study. Material properties and thermal expansion coefficient of FG sheets are assumed to vary continuously along the thickness according to either power-law (P-FGM) or sigmoid function (S-FGM) in terms of the volume fractions of the constituents. Equations of stability are derived based on the generalized higher-order shear deformation beam theory. Thermal loads are supposed to be constant, linear or nonlinear distribution along the thickness direction. An accurate form solution for nonlinear temperature variation through the thickness of S-FGM and P-FGM sandwich beams is presented. Numerical examples are presented to examine the influence of thickness ratio, the inhomogeneity parameter and the thermal loading kinds on the thermal buckling response of various types of FG sandwich beams.

Oignon (Allium cepa L.) est une culture maraîchère présentant un atout économique important pour les paysans Camerounais. Cette étude visait à faire un diagnostic de production de l’oignon dans la partie Septentrionale du Cameroun afin de développer des stratégies d’amélioration durable de cette filière. Une enquête a été menée pour déterminer le profil des acteurs de la filière oignon, les variétés cultivées, les techniques culturales ainsi que les contraintes de production. Les enquêtes s’étaient déroulées en 2017 auprès des acteurs de la filière oignon. L’échantillonnage était constitué de 60 personnes dans chacune des trois régions du Grand Nord Cameroun, soit un échantillonnage global de 180 personnes. Les résultats montrent que la plupart des acteurs sont des producteurs et sont 1,47 fois plus nombreux que les commerçants. 04 variétés d’oignon sont cultivées : Goudami, Chagari, Belami et violet de Galmi. La variété Goudami avait un rendement en bulbe élevé (10 à 35 t/ha), une durée de conservation des bulbes plus importante et est la plus cultivée. La quasi-totalité (69%) des producteurs utilise les engrais chimiques pour améliorer le rendement de cette culture. Ces informations serviront de base de données dans le programme de perfectionnement de la filière oignon au Cameroun. English title: Diagnosis of onion production in the Northern Part of Cameroon Onion (Allium cepa L.) is a market garden crop that is a major economic asset for Cameroonian farmers. This study aimed at diagnosing onion production in the Northern part of Cameroon in order to develop strategies for onion sustainable improvement. A survey was conducted to determine the actors profile relative to onion sector, varieties grown, crop techniques as well as production constraints. The surveys were conducted in 2017 among actors of onion sector. The sample consisted of 60 people in each of the three regions of Far North Cameroon, for an overall sample of 180 people. The results shown that most of the actors are producers, they are 1.47 folds greater than traders. Four onion varieties are grown in the Northern part of Cameroon: Goudami, Chagari, Belami and Galmi violet. The Goudami variety presents high bulb yield (10 to 35 t/ha) and longer bulb shelf life, and is the most widely cultivated. Almost all (69%) of the producers use chemical fertilizers to improve onion growth. This information will be used as a database to improve the performance of onion sector in Cameroon.

Drilling is a chip machining process widely used in manufacturing .The term drilling includes all methods for making cylindrical holes in a work piece with chip cutting tools. There are many applications where drilling is used, such as drilling holes in PCBs. Robotic systems are used today to perform the drilling process. A problem that affects the use of these systems is the drilling sequence, as there are usually a number of points to visit. The determination of the drilling sequence is similar to the problem of synchronization of movement and travel time. The main objective is to optimize the time and trajectory of the three axes robot equipped with an automatic drill that seeks the best performance. In this paper, we have built a genetic optimization and problem solving algorithms to shorten the machining time to drill a given group of holes and reduce machining costs in order to improve the efficiency of the machining process as well robotic machining with three axes without degradation of the precision of the movement. The results of the experiments show that the proposed approach is feasible and practical. It is particularly useful in planning and scheduling systems for real-time manufacturing processes.

The investigation of multiple crack interactions in fracture mechanics is important to predict the safety and reliability of structures. This paper introduces a numerical investigation used to calculate the J-integral of the main crack behaviour emanating from a semicircular notch and double semicircular notch and its interaction with another crack which may occur in various positions in (TiB/Ti) FGM plate subjected to tensile mechanical load. Young’s modulus of the functionally graded material plate varies along the specimen width (notch radius direction r-FGM) with exponential-law (E-FGM) function. Further, the Poisson’s ratio is taken as a constant in normal direction. For this purpose the variations of the material properties are applied at the integration points and at the nodes by implementing a subroutine USDFLD in the ABAQUS software. The variation of the J-integral according to the position, the length, and the angle of rotation of cracks is demonstrated. The variation of the J-integral according to the position, the length, and the angle of rotation of cracks are examined; also the effect of different parameters for double notch FGM plate is investigated as well as the effect of band of FGM within the ceramic plate to reduce J-integral. According to the numerical analysis, all parameters above played an important role in determining the J-integral.

Objective of this work is to optimize the structural configuration of laminates in terms of design for the maximization of buckling resistance of laminates under the effect of constraints. The predominant design parameter is the orientation of the fibers in the layers of the laminate. High-order deformation theory is used in the mathematical formulation in the buckling analysis of stratified composite plates. For this purpose, we will use the optimization technique genetic algorithm taking into account the various factors: number of fibers, geometric ratio, load ratio and boundary conditions.

The main objective of our work is to optimize the positional and orientation error of a platform using the direct geometric model of a parallel plane manipulator robot. It is well known that the main disadvantage of parallel manipulators is the existence of singularities within its workspace, the adaptive neuro-fuzzy solution is proposed in this study. Intermediate methods have been used to determine the optimal solution. The first method is a graphical method which determines all possible positions of the platform based on the intersection of circles. The second method is the polynomial method used to calculate the coordinates of the center of gravity and the orientation of the platform. Matlab programming simulation of these methods makes it possible to find all the solutions deduced from these methods. The analysis shows that the polynomial method is the one that provides the optimal solution.

This work is consisted to investigate the vibration behavior of FGM beams under different boundary conditions with diverse volume fraction. The main objective in this paper is to study the thickness influence of the sandwich beams skin on the frequencies of the structures. The classical Euler-Bernoulli theory (CLBT) with assuming that the material properties of the FGM layer will evaluated continuously in the thickness direction according to the power law (P-FGM) is used to derived the equation of motion. The frequencies obtained are compared with the natural frequencies of a two-material and those of the base materials.