Although microbial biomass is a useful index in ecological research, more specific investigations of the microbial community will improve our understanding of these systems. The fungal:bacterial ratio is one such index that can improve
our understanding of microbial community responses to N input. Though there is some overlap in the physiological capabilities of fungi and bacteria, there are important differences that are likely to affect their response to
environmental changes. For example, the average C:N ratio of fungi is 15, versus 6 for bacteria, suggesting that bacteria
are able to use substrates of a lower C:N ratio than fungi