BioChar Amendments for Improved Plant Microbiome and Crop Health

Plant-based Environmental Control and Life Support Systems (ECLSS) enable human existence beyond Low Earth Orbit (LEO) by providing oxygen, water and food. The root modules are key to success of sustainable plant-based ECLSS. In microgravity, hydroponics is not viable as gases separate from fluids, thus plants are grown in soil substrates, which are bulky and must be maintained for optimal plant growth. Soil substrate selection also impacts ECLSS self-sufficiency. Savings in resupply mass and volume are possible if soil is developed in-situ from regolith found on moons or planets. Biochar, a soil amendment used by ancient civilizations to improve soil fertility that promotes plant health and root zone microbes, can be produced by pyrolysis of plant biomass. The goal is to study the effect of biochar on sequential crop plantings in a single root module. The objectives are: 1) follow changes in root-microbe interactions using metagenomic techniques and next-generation sequencing, 2) measure changes in microbial populations during sequential cropping in a single root module, and 3) examine effect of biochar amendments on soil microbe communities and plant growth. 

This study requires the characterization of root-microbe interactions, which can only be accomplished using state-of-the-art metagenomic techniques. Two 3D-printed root modules, developed at KSC for the Advanced Plant Habitat spaceflight growth chamber, will be planted with two soils: 1) Turface 1-2 mm, and 2) Turface 1-2 mm amended with biochar. Wheat plants will be used because they grow fast and have extensive roots. Each root module will be planted, harvested after 20 days of growth, dried by removing water with a syringe, and replanted three additional times without removing the roots from the previous crops. Thus, the roots from each harvest remain and decay in each root module. Dynamic changes in microbial communities will be followed using metagenomic analysis of 6 soil core samples from each root module per planting. The goal is to characterize plant growth and changes in microbial population from croppings in a single root module.