ABSTRACT: This research aimed to investigate the influence of Arbuscular Mycorrhizal Fungi (AMF) species Rhizoglomus macrocarpium (GM); Rhizoglomus irregularis (GI) and Rhizoglomus fasciculatum (GF) inoculation, under alkaline soil conditions, on the Respiration of Microbial Soil (RMS) through the emission of CO₂, in an attempt to increase soil health and subsequently the plant growth and productivity. Nitrogen (N) and Potassium (K) fertilizers were applied at the rate of 30 g NH₄NO₃ and 20 g K₂SO₄ per seedling. Three levels of phosphorus fertilizer (calcium superphosphate (15.5 % P₂O₅)) were applied before filling the pots. In AMF pots, one week before planting, the soil was inoculated with 30 ml of AMF inoculums. Also, 20 ml of AMF inoculums were added with the seedlings of guava. Every day, tap water was used to irrigate all of the pots. The guava seedlings were harvested 120 days after planting. The results showed that all AMF species were effective on plant growth and P uptake in guava (Psidium guajava L.) seedlings. The AMF species GI developed the plant growth and P content of guava seedlings compared to other AMF species. The guava (Psidium guajava L.) seedlings inoculation with AMF led to increased soil microbial activity this is supported by evidence of increased RMS and CO₂, this resulted in improving soil health and increasing the availability of elements in the soil, resulting in increased P uptake by plants and increased plant growth.