Utilization of Recovered Inorganic Nutrients From Composted Fresh or Oven-Dried Inedible Plant Biomass for Supporting Growth of Wheat in a BLSS 2001-01-2273

The use of composting technology is attractive to NASA’s Bioregenerative Life Support System (BLSS) research because it offers a potential reduction in system costs when compared to other waste recycling approaches. Water-soluble leachates from 28-day composted fresh or oven-dried inedible wheat biomass were amended with reagent-grade nutrients to be inorganically equivalent to ½-strength Hoagland’s (control) replenishment solution. A portion of the fresh and oven-dried compost leachate was filtered to remove large organic particles and a majority of the microflora, and wheat plants were grown hydroponically on these amended leachates. For both the fresh and oven-dried compost leachate treatments, filtering the leachate had no effect on plant response. No significant difference was observed between the fresh compost leachate treatments and the control. However, growing wheat plants on the oven-dried compost leachate treatments showed significant reductions in growth compared to the control. These results suggest that the additional microbial loading and organic particulates are not responsible for previous observations of reduced growth for plants grown on compost leachates. Additionally, 28 days is sufficient to remove any phytotoxic properties from fresh compost, however a longer composting time may be necessary for composting oven-dried composter feed material.