Abstract
The use of waste-derived fertilizers, also known as bio-based fertilizers (BBFs), for the production of ready-to-eat vegetables can efficiently contribute to sustainability and circularity. However, studies on the efficiency and safety of these fertilizers are needed. Thus, this study aimed to examine and characterize the effects of combined application of BBFs on lettuce yield and quality and soil properties in a trial conducted under open field conditions. The eight experimental treatments included green- or food waste compost combined with either human urine, food waste digestate or synthetic fertilizer and compared to treatments with synthetic fertilizer alone or in combination with manure. The control treatment received no BBF or other type of fertilizer. The results showed statistically similar fresh lettuce yields after 48 days among the treatments, all of which were larger than the yield of the unfertilized control treatment. The highest fresh yield (73 t ha−1) was observed with the combination of manure and synthetic fertilizer. Yield in treatments that received green waste or food waste composts tended to decrease slightly, more likely due to nitrogen immobilization after the application of incompletely stabilized composts and the low initial mineral N. Nitrate contents in fresh lettuce leaves were below the EU limits (3000 mg kg−1) in all the treatments. Analysis of pathogens and trace elements present in aboveground lettuce showed no significant risk. The application of BBFs also appeared to maintain the soil pH compared to synthetic fertilizer treatments. The important nutrient and carbon contents of BBFs and their positive effect on lettuce yield associated with their non-harmful impact on lettuce quality suggest that BBFs can be used for vegetable production and to increase the soil carbon stocks and contribute to city sustainability.
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Claims 10
Claim · model-written summary
Fertilized treatments had statistically similar lettuce fresh yields after 48 days.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- treatmentse0
- Outcome
- fresh lettuce yieldse0
- Direction
- statistically similare0
- Qualifier
- after 48 dayse0
- Comparator
- among the treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“statistically similar fresh lettuce yields after 48 days among the treatments”
Claim · model-written summary
All fertilized treatments yielded more lettuce than the unfertilized control.
- Taxon
- lettuceLactuca sativat0
- Treatment
- treatmentse1
- Outcome
- yielde0
- Direction
- largere0
- Comparator
- unfertilized control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all of which were larger than the yield of the unfertilized control treatment”
e1“among the treatments”
t0“lettuce”
Claim · model-written summary
Manure plus synthetic fertilizer produced the highest fresh lettuce yield, 73 t ha−1.
- Taxon
- lettuceLactuca sativat0
- Treatment
- combination of manure and synthetic fertilizere0
- Outcome
- fresh yielde0
- Direction
- higheste0
- Value
- 73 t ha−1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest fresh yield (73 t ha−1) was observed with the combination of manure and synthetic fertilizer.”
t0“lettuce”
Claim · model-written summary
Green or food waste compost treatments tended to reduce lettuce yield slightly.
- Taxon
- lettuceLactuca sativat0
- Treatment
- green waste or food waste compostse0
- Outcome
- Yielde0
- Direction
- decreasee0
- Qualifier
- tended to decrease slightlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield in treatments that received green waste or food waste composts tended to decrease slightly”
t0“lettuce”
Claim · model-written summary
The authors suggest nitrogen immobilization and low initial mineral N likely explain the lower yields with compost.
- Taxon
- lettuceLactuca sativat0
- Outcome
- Yielde1
- Qualifier
- nitrogen immobilization after the application of incompletely stabilized composts and the low initial mineral Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“more likely due to nitrogen immobilization after the application of incompletely stabilized composts and the low initial mineral N.”
e1“Yield in treatments that received green waste or food waste composts tended to decrease slightly”
t0“lettuce”
Claim · model-written summary
Lettuce leaf nitrate content was below the EU limit in every treatment.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- leavese0
- Outcome
- Nitrate contentse0
- Direction
- belowe0
- Value
- 3000 mg kg−1e0
- Qualifier
- in all the treatmentse0
- Comparator
- EU limitse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrate contents in fresh lettuce leaves were below the EU limits (3000 mg kg−1) in all the treatments.”
Claim · model-written summary
Pathogen analysis of aboveground lettuce showed no significant risk.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- abovegrounde0
- Outcome
- pathogense0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Analysis of pathogens and trace elements present in aboveground lettuce showed no significant risk.”
Claim · model-written summary
Trace element analysis of aboveground lettuce showed no significant risk.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- abovegrounde0
- Outcome
- trace elementse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Analysis of pathogens and trace elements present in aboveground lettuce showed no significant risk.”
Claim · model-written summary
BBF application appeared to maintain soil pH relative to synthetic fertilizer.
- Taxon
- lettuceLactuca sativat0
- Treatment
- application of BBFse0
- Outcome
- soil pHe0
- Direction
- maintaine0
- Comparator
- synthetic fertilizer treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The application of BBFs also appeared to maintain the soil pH compared to synthetic fertilizer treatments.”
t0“lettuce”
Claim · model-written summary
The authors suggest BBFs for vegetable production and increasing soil carbon stocks.
- Taxon
- lettuceLactuca sativat0
- Outcome
- vegetable production and to increase the soil carbon stockse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“BBFs can be used for vegetable production and to increase the soil carbon stocks”
t0“lettuce”
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See all 249 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.