The aim of the study was to investigate the effects of five plant growth-promoting rhizobacteria (PGPR) (Bacillus panthothenicus; Pseudomonas Cichorii; Pseudomonas Putida; Pseudomonas syringae and Serratia marcescens) on the growth and yield of maize on a ferruginous soil under field condition. Maize seeds were inoculated with 10 ml of bacterial suspension. Study was conducted in a completely randomized design with fifteen treatments and three replicates. A half-dose of recommended (13, 17, 17 kg•ha −1) NPK was applied 15 days after emergence. The results show that the Serratia marcescens + 50% NPK treatment yielded the best results for height, fresh underground biomass, dry aboveground biomass, dry underground biomass, and grain yield with respective increases of 41.09%, 217.5%, 213.34%, 93.82%, and 39.05% compared to the control. Maximum stem diameter (increases of 49.65%) was recorded in the plants treated with 100% NPK (full dose NPK) while the highest leaf area (466.36 ± 9.57 cm 2), obtained on plant treated with Pseudomonas putida + 50% NPK was 32.08% greater than in the non-inoculated control. Our results suggest the use of these rhizobacteria as biological fertilizers for enhancing the growth and maize seed yield in ferruginous soil in the North of Benin.

Le coton est la principale culture de rente au Bénin. L'accroissement continu des superficies cultivées a entraîné la sédentarisation des cultures avec pour corollaire la dégradation des sols et la baisse des rendements. L'objectif de l'étude est d'évaluer le niveau de fertilité des sols des bassins cotonniers du Bénin. Ainsi, 30 échantillons de sol ont été prélevés auprès de 30 producteurs de coton. Les résultats ont montré des sols sablo-limoneux avec un taux d'argile de 7,38 à 12,65%. La teneur en azote varie de 0,055 à 0,076% avec un pH de 5,7 à 6,5. Le taux de matière organique est compris entre 1,20 à 1,52%. La somme des cations échangeables varie de 3,98 à 6,98 cmol + /kg et la capacité d'échange cationique (CEC) entre 5,35 à 7,91 cmol + /kg. Le phosphore assimilable est compris entre 5 et 13 cmol + /kg. En définitive, les sols présentent de bonnes propriétés physiques, de piètres caractéristiques chimiques et par conséquent un faible niveau de fertilité, ce qui compromet la durabilité du système de production. L'application des amendements organiques et minéraux est donc indispensable pour le relèvement du pH et de la teneur en matière organique de ces sols.

L'objectif de l'étude est d'analyser l'influence de la fertilisation N, P et K sur les caractéristiques physico-chimique et organoleptique du jus Cayenne lisse produit au Bénin. Un essai en plan factoriel NPK complet a été installé à Soyo, un village de la commune d'Allada du Département de l'Atlantique en République du Bénin. Les traitements NPK appliqués en unités fertilisantes exprimées en g/plant et randomisés dans quatre blocs ont été les suivants : T1:

Feeding the world in 2050 requires us to find ways to boost yields of the main local crops. Among those crops, cowpea is one of the grain legumes that is playing an important role in the livelihood of millions of people in West Africa, especially in Benin. Unfortunately, cowpea on-farm yields are very low. In order to understand the main factors explaining cowpea yield gaps, we collected and analyzed detailed survey data from 298 cowpea fields in Benin during the 2017, 2018 and 2019′s rainy seasons, respectively. Composite soil samples were collected from cowpea fields and analyzed in the laboratory. Data on farm field management practices and field conditions were recorded through interviews with 606 farmers. Average cowpea grain yields were low and seldom surpassed 700 kg ha−1 on farmer’s fields. Significant differences were observed between cowpea grain yields from northern to southern Benin (p < 0.05), and the lowest yields were observed in northern Benin. These low yields are related to crop management practices, soil nutrient contents, and the interaction of both. According to the model of regression tree from northern to southern Benin, the use of mineral fertilizer, insecticide sprays to control pests, and the improvement of phosphorus, nitrogen, potassium (P, N, K) and cation sum content in the topsoil would increase cowpea grain yields. Insect pests, diseases, and soil fertility decline are the largest constraints limiting grain yield in Benin. Future research should focus on formulating site-specific fertilizer recommendations for effective cowpea cultivation in Benin, as well as the control of insect pests and diseases.

KEYWORDS ABSTRACTThe aim of this study was to assess the combined effects of the three plant growth promoting Rhizobacteria (Azospirillum lipoferum, Pseudomonas fluorescens and Pseudomonas putida) and a biostimulating molecule (chitosan) on plant growth parameters and seeds yield of maize in southern Benin. This study was conducted in reddish ferrous soil with fisher block experimental design. Maize seeds were soaked into chitosan solution for 12 hours and introduced into a seed hole with bacterial suspension. Experimental maize plants were fertilized by half or complete dose of NitrogenPhosphorus-Potassium (NPK) and Urea. Result of the study revealed that the combination of P. fluorescens along with chitosan and half dose of NPK-Urea increased maize height, circumference and seeds yield of 10.18%, 22.05% and 44.10% respectively. Furthermore, the produced biomass increased 71.43% compared to the control in the combination of P. fluorescens, chitosan and complete dose of NPK-Urea. Results of study suggesting that PGPR and chitosan can be used as an effective biological fertilizer combination for increasing maize production under field conditions.