Perennial cultivation of green pepper provides pest suppression, ecosystem development and high crop yield

Perennial cultivation (PC) provides economic benefits to farmers and environmental benefits to society such as soil protection. However, little is known about the effects of PC on soil pest occurrence. This 4-year study used overwintered green pepper (GP) and root-knot nematodes (RKN) as a model plant–soil pest system. We compared the levels of RKN, its antagonists, and other organisms in strip-shaped PC microplots to those of annual cultivation (AC) and no-tillage AC (NT) microplots. To promote RKN occurrence, we inoculated the ends of all microplots with RKN in the spring of year 3 of study. During autumn in years 3 and 4, we determined abundance of RKN and antagonistic animals, DNA operational taxonomical units (OTUs) counts of antagonistic microbes. The results showed that the rate of RKN occurrence was lower in PC and NT than in AC due to minimal soil movement, rather than to suppression by antagonists, although some antagonists such as collembolan and nematode-trapping fungi increased in PC. Moreover, plant biomass was higher in PC than in NT and AC during fruiting period due to persistence of the plant body over years. We also found signs of ecosystem development in PC, which is an essential background for pest suppression: the maturity index (a measure of disturbance) of the nematode community, fungal diversity, frequency of plant and animal symbionts/parasites were greater in PC than in NT or AC. These findings suggested that ecosystem development had commenced within the 4-year study period. We conclude that the long-lasting plant body and undisturbed soil environment are specific to PC, and could provide agronomical and ecological benefits. [Display omitted] •Perennial cultivation (PC) and no-tillage (NT) reduced Meloidogyne (RKN) levels.•Minimal soil movement was the main factor influencing RKN reduction.•More RKN antagonists were found in PC than in NT and annual cultivation.•PC had diverse nematode and fungal communities and frequent plant/animal symbionts.•Long-lasting plant biomass leads to higher crop yield in PC.