Feeding Mars: A pilot study growing vegetables using aquaponic effluent fertiliser in simulant and analogue Martian regoliths

Abstract

The Feeding Mars study was devised as a small, pilot proof of concept study to research the potential for using aquaponic effluents as an additive to regoliths which on Mars and the Moon are devoid of organic material and thus lacking microbes which assist in the delivery of water and nutrients to the plants via their roots. This research investigates aquaponics as a way to potentially produce fish and vegetal products in regoliths on Mars and the Moon as well as in extreme environments on Earth. In order to settle on Mars, settlers will have to grow their own food in systems that are self-perpetuating, with little or no inputs being brought from Earth once these systems have been established. This means that nutrients from the fish water can be used to grow plants in the hydroponic parts of the aquaponic system but also potentially in the Martian regoliths which are treated with effluents taken from aquaponic systems. Once production is established additional nutrients can be sourced from the arisings and waste, both from the fish (that are processed and eaten) and the plants, which can be used as compost to turn the regoliths into soil. In order to have fish in space, there is also the need for the systems to be self-sustaining in the production of fish feed. The key outcomes of the project were that all the species grown (potatoes, tomatoes, dwarf beans, carrots, lettuce, spring onions, chives and basil) indicate the potential to be grown in regoliths with the addition of aquaponic effluents. A significant result was that on the whole the plants that were grown with the addition of aquaponic effluents were greener than those grown in the horticultural soil, indicating that the nutrient supply was adequate. However, a key lesson learned is that germination and thus development of the plants grown in the Mars simulant and analogue was slower than those grown in the horticultural soil. Thus, developing nutrients in the soil before planting is necessary as it is with agriculture and horticulture practices on Earth, where manuring/fertilization occurs before planting. The consequence of this research, and the envisaged research to follow is not only for extra-terrestrial environments. The Earth has its own hostile environments, characterised with regoliths and other unproductive soils, and aquaponic water and aquaponic wastes can readily be envisaged as providing solutions to growing nutritious food in areas where agriculture is not currently viable. The research was undertaken in an exhibition gallery setting at the University of Greenwich in order to encourage public interest and dialogue, which it did.