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

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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

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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.
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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.
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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, Hoaglands (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 (5050 peat/vermiculte). Hoaglands (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.