|Authors: ||C.L. Mackowiak, G.W. Stutte, R.M. Wheeler, L.M. Ruffe, N.C. Yorio|
|Keywords: ||recirculating hydroponics, monoculture, polyculture, soybean, tomato|
Recirculating hydroponic systems are being used to test the feasibility of using crops in NASA's Advanced Life Support (ALS) systems for long duration space missions.
If crops can be grown in shared compartments with common nutrient solutions, this may reduce system complexity and improve system efficiency.
Tomato and soybean are two crops proposed for ALS systems that are productive in a similar environment.
Tomato (Lycopersicon esculentum Mill.) cv.
Reimann Philipp 75/59 and soybean (Glycine max L. Merr.) cv.
Hoyt were grown in a controlled environment chamber using recirculating hydroponics.
Each species was grown in separate culture trays with either its own nutrient delivery system (monoculture) or a nutrient delivery system shared with the other species (polyculture). A concentrated nutrient stock was added to maintain an electrical conductivity of 1.2 dS m-1. Tomatoes were harvested weekly, beginning approximately nine weeks into the study, and all biomass was harvested at 90 days after planting.
The study was repeated once.
There were no significant differences in soybean or tomato yields between plants grown in monoculture or polyculture systems.
Tomato fruit fresh mass averaged 30 kg.m-2. Soybean seed dry mass averaged 420 g.m-2. Crops differed in water uptake, acid requirement for pH control, and nutrient uptake but the polyculture system had no effect on these parameters.
Polyculture appears to be a viable option for these species.
Additional testing is needed to see what other crops are compatible and what happens over several cropping cycles.
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