The symbiotic association (plant-soil-microorganisms) has an important role in nitrogen (N) and phosphorus (P) uptake. The main objective of this study is to assess the potential of fungal and rhizobial symbionts as well as the importance of plant-soil-microorganism interactions on microbial dynamics. The upland rice and the beans were cultivated in mono or in co-culture using the rhizospheric soil of the upland rice and beans collected on plots treated with different levels of organic and mineral fertilizers. What about saying: Microbial (fungal and rhizobial) inoculate were constituted by root fragments (rice or bean) collected from previous crop and coded as I1 (root fragments from rice), I2 (root fragments from bean) and I3 (mixed root fragments from rice and bean). The results showed that soils inoculated with I1 and I3, were characterized by high phosphatase activity. These two treatments enhance also the amount of nitrogen and phosphorus in the aerial part of upland rice intercropped with bean. These results suggest that the bean with its symbiont can be considered as ecological engineers that stimulate the biological functioning of soils and is beneficial for upland rice cultivation.