Background:

Mycorrhizal fungi (MF) inoculation in cover crops increases nutrient uptake and the settlement of other symbiotic microorganisms like nitrogen-fixing bacteria. In addition, competition of these microorganisms within the soil affects the efficiency of the MF inoculation. Furthermore, plant responses to the introduction of external inoculums differ from the responses of native inoculums.

Objective:

Compare the efficiency between an introduced and native inoculum within the growth of six cover plants and their influence in the nitrogen fixing bacteria establishment.

Methods:

Six species of cover crops were sown in sterilized and unsterilized soils. Soils were inoculated with introduced and native MF and the growth variables were measured at 60 days after inoculation.

Results and conclusions:

Introduced fungi inoculation increased the value of the growth variables and the nodule number in sterilized soil showing a relationship between nodule weight and the mycorrhizal root colonization percentage. A suppressive effect was observed in the crops because of the native microbial community. In brief, the use of MF introduced inoculants showed an advantage over the native species.