Work

Manure and chia mucilage as structure-forming agents in lunar and martian regolith simulants: a bio-based approach to substrate conditioning

Year: 2026

Type: article

Abstract: Space agriculture research is geared towards finding efficient growth media that combine nutrient availability with suitable physical properties for use in bioregenerative life-support systems and long-term missions. On Earth, lunar and martian regolith simulants provide experimental analogues for the development of strategies optimizing mineral substrates for plant growth. In this research, monogastric manure at 30% w/w and chia ( Salvia hispanica L.) seed mucilage at 0.2, 0.5 and 1% w/w were added to LHS-1 and MMS-1 regolith simulants as organic amendments to evaluate their effects on water-stable particle aggregation. The amended mixtures were then incubated for 1, 7 and 30 days and analyzed by wet sieving. Aggregate stability was assessed as the percentage of the initial dry mass retained in four aggregate-size classes (>1, 0.5–1, 0.2–0.5 and 0.1–0.2 mm). The elemental composition of manure amended fractions as well as a seed mucilage–simulant bonding assay was also evaluated. Manure increased the > 1 mm water-stable fraction, whereas mucilage produced concentration- and size-dependent responses, with higher concentrations generally favoring larger particle aggregates. LHS-1 showed greater retention in the >1 mm class, whereas MMS-1 in the intermediate fractions. Most structural changes occurred within 7 days. Higher contents of C, N, H and S were detected in the larger fraction of manure-amended samples. During water flow disturbance, chia seed mucilage retained more simulant than rocket diaspores, suggesting that greater adhesion of the particles depends on simulant type. These findings indicate that the investigated organic inputs promote distinct patterns of particle structuring in regolith simulants, providing a mechanistic framework for further studies on their physical conditioning as growth media for future space agriculture research.

Source: Frontiers in Soil Science

DOI: 10.3389/fsoil.2026.1999715