Articles
MAINTAINING CONSTANT ROOT ENVIRONMENTS IN FLOATING HYDROPONICS TO STUDY ROOT-SHOOT RELATIONSHIPS
Article number
507_25
Pages
215 – 222
Language
English
Abstract
The design and operation of a floating hydroponic system are described.
The nutrient solution temperature and dissolved oxygen concentration in this hydroponic system were maintained with two simple control mechanisms.
During a 24 day growth trial with lettuce (Lactuca sativa L., cv Vivaldi), nutrient solution temperature was controlled to 24 ± 0.3 °C and the dissolved oxygen concentration to 8.4 ± 0.2 mg-L-1. Measurements of shoot fresh and dry mass as well as root dry mass of plants aged from 11 to 35 days after sowing were taken.
Desired nutrition and pH levels in this closed recirculation system were maintained manually.
Greenhouse air temperature and daily integrated light level were precisely maintained at consistent levels throughout the experiment.
Example data of plant response showed a rapid decline in root-shoot ratio shortly after transplant, followed by a gradual decline towards final harvest (35 days after sowing). Root-shoot ratio at final harvest was 10%. Percentage of shoot dry matter declined steadily from 8% at transplant to 4% at final harvest.
Results showed an improved environment control can result in highly uniform plant production.
The nutrient solution temperature and dissolved oxygen concentration in this hydroponic system were maintained with two simple control mechanisms.
During a 24 day growth trial with lettuce (Lactuca sativa L., cv Vivaldi), nutrient solution temperature was controlled to 24 ± 0.3 °C and the dissolved oxygen concentration to 8.4 ± 0.2 mg-L-1. Measurements of shoot fresh and dry mass as well as root dry mass of plants aged from 11 to 35 days after sowing were taken.
Desired nutrition and pH levels in this closed recirculation system were maintained manually.
Greenhouse air temperature and daily integrated light level were precisely maintained at consistent levels throughout the experiment.
Example data of plant response showed a rapid decline in root-shoot ratio shortly after transplant, followed by a gradual decline towards final harvest (35 days after sowing). Root-shoot ratio at final harvest was 10%. Percentage of shoot dry matter declined steadily from 8% at transplant to 4% at final harvest.
Results showed an improved environment control can result in highly uniform plant production.
Authors
A.J. Both, L.D. Albright, S.S. Scholl, R.W. Langhans
Keywords
dissolved oxygen, Lactuca sativa L., lettuce, temperature
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