This article presents the design, implementation and evaluation of performance tests of a motorized feed grinder-mixer made from local materials. The dynamic and dimensional study made, allowed the realization of a prototype of 350 liters in capacity. To assess the uniformity rate of the machine, three types of feed were used, namely: (1) starter, (2) chicken and (3) layer. In addition to food, the coefficient of variability between samples after chemical analysis was obtained for each chosen mixing time. The determination of the different optimal rational models of the homogeneity rate was made with Matlab R2017a to determine the minimum mixing time. The results of this study show that the machine developed allows the homogeneous mixing of 427 kg of feed per hour with a maximum energy consumption of 0.72 Wh/kg. The feed variability coefficient is less than 10% in 12 minutes of mixing, resulting in better homogeneity rates. The specific energy consumption is around 59%. This machine has low environmental pollution (little noise and dust), guaranteed ergonomics and stability; also, maintenance is easy. The estimated cost of developing the prototype is around 381,300 FCFA, or 568,00 USD; this machine is therefore accessible to average breeders. The results of this study also show that, compared to what exists on the Cameroonian market, this machine has several advantages for improving farming techniques and the living conditions of the populations.

A survey was conducted by administering a questionnaire to identify common bean (Phaseolus vulgaris L.) conservation methods used by farmers in the Hauts-Plateaux division, west region of Cameroon. To reduce post-harvest losses of common bean (P. vulgaris) in the study area, a six-month study was carried out on red and black beans. Vegetable powder of tobacco leaves (Nicotiana tabacum) was produced and tested against the bean weevil (Acanthoscelides obtectus). Tobacco leaves were dried to 13.5% moisture content, crushed and sieved to obtain a powder at pH 5.63. This powder and two other synthetic insecticidal powders (Antouka and Protect DP) based on permethrin were incorporated at a dose of 1 g kg-1 in batches of beans. The coated seeds were placed in 125 mL polyethylene boxes containing 100 seeds each, then stored for 6 months in a room at a temperature between 15 and 27 °C. The experimental set-up applied for each variety was a complete randomized design comprising four treatments and four replicates (Control without any treatment, Tobacco, Protect DP, Antouka). Data on perforated seeds, weevil emergence and mortality were observed throughout the experiment. Results showed that 41% of farmers use synthetic insecticides, 36% do not use any substance, 14% wood ash, 9% fir leaves. This study showed that tobacco powder significantly reduced the puncture of beans by weevils, indicating the importance of alternatives means for pest management. It also emerged from this study that the black bean is more resistant to weevils than the red one.