Soil food web is a nonlinearity system with complex structure and multifunctions, and described by three step-up levels of connectedness web, energy flow web and functional web. However, it is difficult to infer directly the structure and function by measuring the biomass of soil organism and calculating the energy flux among the functional groups with modes. Therefore, it is important that searching a simple bioindicator evaluate indirectly the structure and function of soil food web. Nematode is a good biondicator of soil food structure and function because it is the most abundant metazoan with high diversity of species composition, feeding habits, life history strategies and functional guilds, and participate in several links and energy channels within the soil food web, and occupy the central position of soil food web.
The paper reviewed the history,principle, calculation, meaning of nematode fauna analysis (NFA) as well as the application of NFA in managing soil food web. The NFA can be divided four developing stages of individual taxon, life history strategy taxon, functional guild taxon and metabolic footprint. Actually, only the latter two stages give insight into soil food web. The NFA based on functional guilds developed a serial indices through integrating the feeding habit and life history strategy, and indicate the soil food web connectedness and condition, food chain length, decomposition path, the input of external resource and response to disturbance. However, the NFA based on functional guilds only provide the relative proportion of services and functions, but not of their magnitude. The magnitude can be indicated by the NFA based on metabolic footprint that determined by the carbon of nematode biomass and respiration. Seven metabolic footprint indices were developed and some of them, such as enrichment footprint and structure footprint, are corresponding to the enrichment index and structure index that deduced from NFA based on functional guilds. NFA based on functional guild taxon and metabolic footprint had been used widely to evaluate the bottom-up regulation of soil food web through the input of external resource and top-down suppression on plant parasite nematodes.