# Presentation: 246354

## Three Candidate Nutrient Delivery Systems For A Portable, Lightweight Plant Growth Chamber

- By: Charlie M. Stinson, III
- SLSTP CBS
- PI: Oscar Monje Ph.D.
- July 12, 2004

## Introduction

- Long term space travel by humans may be limited by supplies of food, water, oxygen, and power. The success of a long term manned mission depends on efficient technologies enabling the needs of space crews to be met. Plants can provide food and oxygen, as well as recycle water in bioregenerative systems. The efficiency for food production of plant-based bioregenerative systems can be measured by taking into account the amounts of mass and power needed to produce edible biomass. Measurements of the efficiency of food production in bioregenerative systems in spacecraft can be influenced by environmental factors like chamber aeration rates and the presence of volatile organic compounds. A major component of plant-based systems is the nutrient delivery system (NDS), thus three candidate systems were built and evaluated. The focus of the research is to find the simplest NDS system that will grow the healthiest plants in the shortest amount of time. The radish (*Raphanus sativus L*.) was the selected plant for this research because of its quick growth ability and low maintenance.

## Purpose of Research

- Design, build and test three nutrient delivery systems for the root trays from the Biomass Production Educational System
- Hydroponic – re-circulating nutrient solution
- Substrate – time released nutrient
- Conventional Pot – time released nutrient

**Fig 1.** Hydroponic, Substrate-based and Conventional Pot NDS.

## Materials and Methods

- 	Hydroponic, substrate-based, and conventional potting systems were tested using a common  root tray (0.25m2), chamber walls and lighting system (fig. 1). The root trays were planted at the same planting density (160 plants/m2). Light level was 200 umol/m-2s-1 during germination and adjusted to 300 umol/m-2s-1 6 days after planting (DAP). The hydroponic system contains a pump, a reservoir, a tube irrigation system, and a pH controller.  In this system, Hoagland’s (1X) nutrient solution is re-circulated and electrical conductivity was adjusted daily. The substrate-based system contains a controlled pump, a porous tube irrigation system, a root tray (0.25m2) in area, and a stand pipe.  Water was delivered by the stand pipe in this system through the force of gravity. Osmocote, a time released fertilizer (7g/L), supplied nutrients in this system.  1-2mm arcillite was used as the media. The conventional pot system contains a root tray (0.25m2) in area, and twenty planting pots (50:50 peat/vermiculte). Hoagland’s (1x) nutrient solution was delivered by means of a capillary mat. The nutrient solution is delivered to each pot through the capillary mat by capillary action from a water reservoir.

- Conclusions

- The potted NDS had the lowest mass, used the smallest amount of power, required the least amount of time to plant, and it had the smallest biomass.  The hydroponic and substrate-based systems had similar masses, power use, required similar amounts of time to plant, and had nearly the same biomass at 21 DAP.