Mars Regolith Simulant Ameliorated by Compost as in situ Cultivation Substrate Improves Lettuce Growth and Nutritional Aspects

Abstract

Heavy payloads in future shuttle journeys to Mars present limiting factors, making self-sustenance essential for future colonies. Therefore, in situ resources utilization (ISRU) is the path to successful and feasible space voyages. This research frames the concept of planting leafy vegetables on Mars regolith simulant, ameliorating this substrate’s fertility by the addition of organic residues produced in situ. For this purpose, two butterhead lettuce (Lactuca sativa L. var. capitata) cultivars (green and red Salanova®) were chosen to be cultivated in four different mixtures of MMS-1 Mojave Mars simulant:compost (0:100, 30:70, 70:30 and 100:0; v:v) in a phytotron open gas exchange growth chamber. The impact of compost rate on both crop performance and the nutritive value of green- and red-pigmented cultivars was assessed. The 30:70 mixture proved to be optimal in terms of crop performance, photosynthetic activity, intrinsic water use efficiency and quality traits of lettuce. In particular, red Salanova® showed the best performance in terms of these quality traits, registering 32% more phenolic content in comparison to 100% simulant. Nonetheless, the 70:30 mixture represents a more realistic scenario when taking into consideration the sustainable use of compost as a limited resource in space farming, while still accepting a slight significant decline in yield and quality in comparison to the 30:70 mixture.

To Other Planets With Upgraded Millennial Kombucha in Rhythms of Sustainability and Health Support

“…As for Mars, no regolith sample has been brought back so far. Plants were successfully germinated and grown in Mars regolith simulants (Wamelink et al, 2014;Duri et al, 2020), but those differ from the regolith they mimick in ways that are critical to biological experiments. Generally speaking, it is thought that regolith from both bodies would require some physical, chemical, and/or biological modifications (e.g., Ming and Henninger 1994;Maggi and Pallud, 2010;Fackrell et al, 2021) before use as a substrate for plant growth, due to, for instance, poor water retention, low availability (or release up to toxic concentrations) of mineral nutrients, toxins, root damage by abrasive particles, and/or lack of metabolizable nitrogen.…”

“…For the case where such a treatment would not suffice for growing plants of high interest, an approach has been proposed where "firstgeneration plants" (i.e., plants with higher fitness in such an environment, such as Tagetes patula or Kalanhoe daigremontiana) would be grown first, supported by microbial communities, and composted to enrich a protosoil itself used for plants of direct interest such as calorie-dense crops (e.g., Lytvynenko et al, 2006;Zaets et al, 2011). In line with this, Duri et al (2020) suggested planting leafy vegetables on Martian regolith ameliorated with organic materials produced in situ. A composted kombucha mat could be an additional source of nutrients and other plant-supporting biologicals.…”

“…The use of local resources (in situ resource utilization, ISRU) could decrease the reliance of bioprocesses on Earth-imported materials and, thus, improve their cost-effectiveness. Researchers and engineers are, for instance, designing ways of growing plants on lunar or Martian analogue substrates (Lytvynenko et al, 2006;Zaets et al, 2011;Duri et al, 2020), possibly after processing them using microorganisms to release nutritive elements (Auerbach et al, 2019;Castelein et al, 2021).…”

Selected Plant-Related Papers from the First Joint Meeting on Soil and Plant System Sciences (SPSS 2019)—“Natural and Human-Induced Impacts on the Critical Zone and Food Production”

“…In view of a futuristic scenario that foresees the need for the self-sustenance of colonies on Mars due to constraints related to the delivery of food resources from Earth, Duri et al [ 46 ] attempted to grow two lettuce cultivars (green and red Salanova ® ) on Mojave Mars regolith simulant (MMS-1) mixed with different compost percentages (0:100, 30:70, 70:30 and 100:0; v:v ) inside a phytotron open gas exchange growth chamber. The addition of organic residues to MMS-1 ameliorated the quality of the substrate, thus evoking a better crop quality and higher yield.…”

Hydrogels Improve Plant Growth in Mars Analog Conditions

“…Solutions has been reported to improve water use efficiency by plants: based on the ability of organic matter to store water available for plant growth (Hudson 1994), the supplementation with compost has been reported to improve water use efficiency and lettuce growth (Duri et al, 2020;Caporale et al, 2020).…”