Influence of organic fertilization and cultural association practices on bacteria PGPR in a tomato field in Saguia (Niger): Density, morphological and biochemical traits

This study evaluates the impact of cultural practices and cultural associations on the density, morphological and biochemical characteristics of bacteria PGPR in a tomato experimental field in Saguia, Niamey region of Niger. After the experiments, morphological and biochemical analyses (Gram, API 20E) were carried out. The results show that the microbial density varies significantly with the type and dose of fertilizer, with maximum values observed below the recommended dose in ASD medium and under the poultry dropper in PDA medium. The bacterial genera PGPR identified are Bacillus spp., Serratia rubidaea, Burkholderia cepacia and Stenotrophomonas maltophilia, as well as fungi such as Candida non albicans and Aspergillus fumigatus. Crop associations also influence microbial diversity, although less markedly than organic amendments. The study concludes that organic fertilizers, particularly at optimized doses, promote soil biological fertility by stimulating the density and diversity of beneficial microorganisms. These results support the adoption of sustainable agroecological practices to improve market productivity in Sahelian areas.