Drought reduces peanut yield indirectly through regulating soil nematode community in a manipulative field experiment in central China

Drought is a direct limiting factor for crop yield. Drought may also greatly affect soil nematode community due to their dependence on soil water and indirectly reduce crop yield. However, the regulatory role of soil nematodes in this process is poorly understood. In this study, we conducted a manipulative field experiment to study the changes in soil nematode community and peanut yield along an experimental drought gradient. Our results showed that drought decreased the total nematode and absolute and relative bacterivore abundance, nematode channel ratio, and peanut yield, but increased the absolute and relative abundance of fungivores, resulting in a fungal-based and slow energy channel. The structural equation model showed that peanut yield was influenced by all nematode trophic groups. This highlights the important role of soil nematode community in modulating crop production. Specifically, peanut yield was positively correlated with the relative abundance of bacterivores, fungivores, and omnivore-predators, and negatively correlated with the relative abundance of plant parasitic nematodes. In addition, moderate drought enhanced the complexity and stability of nematode interaction network, which is in accordance with the intermediate disturbance hypothesis. The effects of soil nematode community on peanut production should be emphasized in the context of more frequent droughts in the future.