Aeroponic Technology for Accelerated Weathering of Extraterrestrial Regolith to Extract Plant Essential Nutrients and Generate Arable Soils.

Abstract

Advancements in off-world food and fiber production should seek to utilize regolith as a source of nutrients and prepare it for use as a solid plant growth substrate. Towards this goal, aeroponic biowaste streams containing both inorganic nutrients and root system efflux from plants provide an opportunity for accelerated weathering and enhancement of extraterrestrial soils. To test this hypothesis, an aeroponic system was built that contained Martian simulant (Mars Mojave Simulant-2; MMS-2), inert sand, and a no-filter control to evaluate the in-line filters for simultaneous mineral weathering and recycling of biowastes from wheat. The growth performance of wheat in aeroponics was highly productive across all treatments. After inundation with biowastes from the aeroponic system growing wheat for 40 days, MMS-2 sorbed P and K and released Al, B, Ca, Fe, Mn, Na, and S into the nutrient solution. Generated plant biowaste was mixed into MMS-2 and sand treatments, which increased the extractable Fe, K, Mg, P, and S in MMS-2. Substrate chemical properties were quantified (e.g., total C and N, total and extractable elements, pH, EC, particle size, and P species). Augmentation of MMS-2 with aeroponic biowastes followed by amendment with plant residue greatly improved wheat growth compared with the unmodified MMS-2, which resulted in plant death. This technology expands lunar/Martian base agriculture by offering a means to acquire nutrients from weathered regolith while simultaneously improving the fertility of extraterrestrial soils.