Positive effects and mechanisms of simulated lunar low-magnetic environment on earthworm-improved lunar soil simulant as a cultivation substrate

Abstract: With the advancement of crewed deep-space missions, Bioregenerative Life Support Systems (BLSS) for lunar bases face stresses from lunar environmental factors. While microgravity and radiation are well-studied, the low-magnetic field's effects remain unclear. Earthworms ("soil scavengers") improve lunar soil simulant and degrade plant waste, as shown in our prior studies. We tested earthworms in lunar soil simulant mixed with organic waste (from "Lunar Palace 365" experiment) under three magnetic conditions: lunar-low, Earth, and high. Stronger fields increased earthworm oxidative stress (MDA) and impaired neurotransmitters. Weaker fields enhanced substrate cultivability: neutralized pH, increased nutrients, humus, and wheat seedling rate. Microbial analyses showed: (1) Higher fungal Shannon index under high fields indicated impaired digestion; (2) More positive correlations in gut networks suggested slower microbial cooperation (e.g., lignocellulose degradation); (3) Reduced Network Size, Path Length and Modularity confirmed disrupted interactions. This disproves lunar low-magnetic stress on earthworm-soil-waste systems, aiding deep-space BLSS research.