Cropping systems that improve richness convey greater resistance and resilience to soil fungal, relative to prokaryote, communities.

Resistance is the capacity for a community to remain unchanged, and resilience the capacity to return to an original state, in response to disturbance. Increasing species richness may increase both dynamics. In a long-term agricultural field experiment incorporating conventional (CON), conservation (CA), organic (ORG) and integrated (INT) cropping systems, the effects of crop harvest and fallow period on the disturbance of prokaryote, fungal and arbuscular mycorrhizal fungi (AMF) communities were investigated. Prokaryote community structure shifted over the growing season, forming distinct saprotroph- and rhizosphere-dominated communities, and composition was primarily affected by time than cropping system. Species-rich prokaryotes demonstrated the highest resistance/resilience. Cropping system was more important for fungal communities, with resistance highest under CA. CON was particularly detrimental to AMF resistance and resilience. Prokaryote plant-growth promoters and saprotrophs, but not ammonia oxidisers and methylotrophs, were stable functional groups. Cosmopolitan soil fungal genera were stable, but most were not. Glomus AMF were stable, while most other genera were most stable under CA and ORG. These results demonstrate that practices promoting richness increase the stability of soil microbial communities in response to crop removal after harvest, with this effect being more pronounced in fungal (and AMF) communities.