Biochar improves lettuce seedling growth by influencing the nutrient content of simulated lunar soil

The utilization of native lunar soil and recycled organic waste as primary resources will reduce the reliance on terrestrial inputs and improve the self-sufficiency of bioregenerative life support systems (BLSSs) in future lunar bases. A major question to address is the suitability of lunar soil for plant growth and how soil agronomic performance is affected by biochar. Biochar treatments increased the organic matter content and promoted greater availability of N, P, and K in the simulated lunar soil. It also reduced the bulk density and facilitated the optimal distribution of plant roots. Redundancy analysis indicated that the physical and chemical properties of soil pH, alkali-hydrolyzable nitrogen (AN), and total nitrogen (TN) content might be critical factors influencing lettuce growth. The aforementioned analysis suggested that the optimum rate of biochar addition to improve simulated lunar soil is 3%. The results showed that the utilization of pyrolysis for treating solid waste in BLSSs has significant potential, with biochar enhancing the properties of the simulated lunar soil.