Centre for Plant & Water Science - Central Queensland University

Centre for Plant & Water Science 2008 Annual Report
HYDROPONIC PRODUCTION OF A LEAF VEGETABLE PAK CHOI
(Brassica rapa L.CHINESIS GROUP) GROWN WITH BOTH
CHEMICAL (INORGANIC) FERTILIZER AND VERMICAST
EFFLUENT
SUMMARY
Some effects of vermicompost effluent (vermiliquor), formed during the breakdown of
organic wastes by earthworms (vermicomposting), on plant growth and nutrient uptake have
been evaluated in a series of experiments.
The overall purpose of the project is to develop an organic alternative to conventional
inorganic solutions for hydroponically-growing plants and to formulate an organic fertilizer
for the hydroponic production of Pak Choi.
This project is the first to quantify how vermiliquor influences plant growth. By
manipulating such parameters as pH, pH-buffers, ratio of dilution (electrical conductivity),
aeration, and also differences in the type of composting process and the kind of organic
wastes from which vermiliquor derived, growth of hydroponic vegetables can be modiifed.
Worm and vermiliquor production also depend on season and source of food wastes.
The experiments monitored the contribution of the parameters of nutrient solution like
temperature, electrical conductivity, dissolved oxygen, nitrate, ammonium, potassium and
external parameters like shading/solar activity and temperature on growth characteristics
(growth period, leaf area, shoot and root weights).
To increase commercial viability of the project the trial experiments were carried out in
commercially adopted nutrient film technique and pot systems under different climatic
conditions on both batched vermiliquor and in vivo vermiliquor from vermitanks directly
linked to the hydroponic system. The latter, thus created a system of a ‘live’ vermiliquor
recirculating between vermipits and hydroponic units.
All physical, chemical and favourable visual differences of Pak Choi, hydroponically-grown
with organic vermiliquor, compared to a conventional inorganic fertilizer Boxsell.
PROJECT STAFF Principal Investigator:
Co-Principal Investigator:
Others:
FUNDING RIRDC
INCOME $131,100
Elena Churilova
Prof David Midmore
Brock McDonald
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