4.3. Conclusions
The results of the field experiment showed that amendments of organic and inorganic N generate different responses in growth of AMF and saprotrophic fungi. The interaction between these two fungal groups, and the composition of the microbial community in the organic amendments in general, could be a determining factor in the effect generated by the organic amendments. The activity of saprophytic fungi may reduce AMF growth in a similar way as it can reduce bacterial growth, though this aspect needs to be further investigated.
The greenhouse experiment confirmed that two sources of organic N generate a similar effect on AMF growth, but showed low variance between different levels of N. This leads us to believe that the effect of N content might be insignificant or dependent on the origin of the N in the amendment. The N status of the plant did not appear to influence the effect of the organic amendments, which raises further questions about the correlation between N levels and AMF growth.