Detrital subsidy alters the soil invertebrate community and reduces infection of winter wheat seedlings by Fusarium wilt

Biological control of pathogenic Fusarium species through the promotion of detrital food webs is a promising option for agricultural production and could be of high value in organic farming. To obtain quantitative information on the impact of detrital subsidy on the development of Fusarium infection in winter wheat seedlings, we established a 60-day laboratory experiment in which the soil was amended with either a N-poor or a N-rich mixture of straw and compost containing the same amount of organic carbon (200 g C m(-2)). Compared with the control treatment (no subsidy), shoot biomass decreased by 27% in the N-poor mulch treatment and increased by 24% in the N-rich mulch treatment. For both of the added mulch treatments, the population of mycophagous and predatory mites increased fivefold compared to the control. The abundance of Enchytraeidae also increased in both N-poor (by 68%) and N-rich (by 46%) mulch treatments. Unexpectedly, the abundance of gene copies of total soil fungi and of genus Fusarium in particular, as well as the abundance of Fusarium-specific polysaccharide protein conjugate (FPPC), were not affected by either mulch addition. Nevertheless, wheat seedlings were not infected by Fusarium wilt in either mulch treatment, whereas in the control treatment, the infection incidence was about 9%. The quantitative information obtained here may be important for the development of an ecological control method for cereal diseases caused by pathogenic Fusarium species.

Automated summary

The study shows that promoting detrital food webs can effectively control pathogenic Fusarium species and increase crop productivity. Adding detrital subsidy can increase the population of predatory mites and Enchytraeidae, thereby reducing the infection rate on winter wheat.