Effects of resource availability and quality on the structure of the micro-food web of an arable soil across depth

► Litter amendment trigged bottom-up effects in nematode guilds that feed on microbes. ► Enhanced resource supply did not sustain large biomass at higher trophic levels. ► Dominant groups of the food web, even with similar function, exploit different niches. ► Abiotic and biotic environment shaped food web structure more than resource amendment.