Abstract
Urban farms, particularly those utilizing vertical space and hydroponics, have the potential to address many challenges of the existing food system. The use of organic inputs in hydroponics can conserve dwindling non-renewable resources and mitigate greenhouse gas (GHG) emissions associated with inorganic nitrogen (N) fertilizer production and use. The study compared plant growth using organic liquid fertilizer (OLF) from insect and chicken waste in a two-step aerobic bioreactor. Basil (Ocimum basilicum) plants were grown with an inorganic fertilizer control and a novel OLF at two separate locations. In the first part of the study, plant yield, nutrient uptake and tissue elemental composition were used to validate the functional equivalency of OLF versus inorganic fertilizer. The second part of the study used these results to conduct a life-cycle assessment (LCA) to quantify GHG mitigation potential of the novel OLF. N-mass balance showed a liquid nitrogen conversion rate ∼40% for the bioreaction. Solid output from the bioreaction contained approximately 35% of the initial N. N-gaseous loss was approximately 25% of total N-input. Because the nature of gaseous N-loss was unknown, LCA modeled different scenarios varying the percent of gaseous N-loss as N2O, as it is the only nitrogen-based gas with appreciable global warming potential. Models showed that N2O leakage during bioreaction must be below 5% of total N-input for OLF to mitigate GHG emissions associated with fertilizer usage in urban hydroponic production. Further studies should focus on direct quantification and characterization of gaseous N-loss during this type of bioreaction.
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Claims 6
Claim · model-written summary
Organic liquid fertilizer had functionally equivalent basil yield, nutrient uptake, and tissue composition to inorganic fertilizer.
- Taxon
- Basil
Ocimum basilicumt0 - Treatment
- OLFe0
- Outcome
- plant yield, nutrient uptake and tissue elemental compositione0
- Direction
- functional equivalencye0
- Comparator
- inorganic fertilizere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plant yield, nutrient uptake and tissue elemental composition were used to validate the functional equivalency of OLF versus inorganic fertilizer.”
e1“plant yield, nutrient uptake and tissue elemental composition were used to validate the functional equivalency of OLF versus inorganic fertilizer.”
t0“Basil (Ocimum basilicum) plants were grown”
t1“Basil (Ocimum basilicum) plants were grown”
Claim · model-written summary
Bioreaction converted about 40% of nitrogen to liquid nitrogen.
Not reportedTaxon
Verbatim
e0“N-mass balance showed a liquid nitrogen conversion rate ∼40% for the bioreaction.”
e1“N-mass balance showed a liquid nitrogen conversion rate ∼40% for the bioreaction.”
Claim · model-written summary
Bioreaction solid output retained about 35% of initial nitrogen.
Not reportedTaxon
Verbatim
e0“Solid output from the bioreaction contained approximately 35% of the initial N.”
e1“Solid output from the bioreaction contained approximately 35% of the initial N.”
Claim · model-written summary
Bioreaction gaseous nitrogen loss was about 25% of input.
Not reportedTaxon
Verbatim
e0“N-gaseous loss was approximately 25% of total N-input.”
e1“N-gaseous loss was approximately 25% of total N-input.”
Claim · model-written summary
The LCA found N2O leakage must remain below 5% of input for organic liquid fertilizer to reduce hydroponic fertilizer emissions.
- Taxon
- BasilOcimum basilicumt0
- Outcome
- mitigate GHG emissionse0
- Value
- below 5% of total N-inpute0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Models showed that N2O leakage during bioreaction must be below 5% of total N-input for OLF to mitigate GHG emissions associated with fertilizer usage in urban hydroponic production.”
e1“Models showed that N2O leakage during bioreaction must be below 5% of total N-input for OLF to mitigate GHG emissions associated with fertilizer usage in urban hydroponic production.”
t0“Basil (Ocimum basilicum) plants were grown”
t1“Basil (Ocimum basilicum) plants were grown”
Claim · model-written summary
The authors recommend directly measuring and characterizing gaseous nitrogen loss from this bioreaction.
- Outcome
- direct quantification and characterization of gaseous N-losse0
Not reportedTaxon
Verbatim
e0“Further studies should focus on direct quantification and characterization of gaseous N-loss during this type of bioreaction.”
e1“Further studies should focus on direct quantification and characterization of gaseous N-loss during this type of bioreaction.”
The same questions in other papers
fertilization · quality: general · Ocimum basilicum (basil)Results agree
6 papers in the same direction as this paper
- positive
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3 papers more in this group
See all 7 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.