Irish potato (Solanum tuberosum) is one of the world’s most consumed staple worldwide and an important crop in terms of food security in the face of population growth and increased hunger rates. Potato yields in Cameroon have often been low as a result of decrease in soil fertility. Soil fertility has often been regarded as the chemical and physical properties of soil, with the microbial aspect often being ignored. An experiment was carried out in Bambili, Cameroon to evaluate the effect of two organic fertilizers (indigenous microorganism fertilizer, IMO, and effective microorganism fertilizers, EM) on the yield of Irish potato and to identify some soil bacteria and fungi. A randomized complete block design with three treatments (EM, IMO and control), and four replications was used. Fertilizers were applied one week before planting and repeated four and eight weeks after planting. Soil samples were collected before the application of fertilizers, and then 1, 6 and 10 weeks after application of the fertilizers and used to find out microorganisms present in the different treatments at different periods of plant growth. Different culture media were used for the primary cell culture of the bacteria and fungi using the spread plate technique while isolation of pure bacteria cultures was done by streaking. The fresh weight of tubers under IMO fertilizer was higher than those with EM fertilizer and the control. Some microorganisms identified in the different treatments included: Aspergillus, Rhizopus, Penicillium, Fusarium, Saccharomyces, Enterobacteria and Pseudomonas which were present in all the treatments but at different growth stages of the plants. Both IMO and EM fertilizers had significant positive effects on the tuber yield and the soil microbial population in the different treatments.

Keywords: Bacteria, fungi, Solanum tuberosum, tuber yield.