Abstract
Empirical data on the effect of plant density (PD) and length of the vegetative phase (DVP) on plant growth, yield, and cannabinoid concentration of medicinal cannabis (Cannabis sativa L.) are still scarce, leading to a lack of specific cultivation recommendations. We conducted two greenhouse experiments to investigate the effect of PD in the range of 12-36 plants m-2 (D-trial) and DVP in the range of 1-4 weeks (V-trial) on plant morphology, biomass growth of individual plant organs, and CBD concentration of individual inflorescence fractions. Empirical models for the relationships between the investigated plant traits and PD/DVP were created using linear regression analysis preceded by a lack-of-fit test. An increase in PD led to a linear decrease in inflorescence yield per plant (p = 0.02), whereas a positive linear relationship was found for inflorescence yield (p = 0.0001) and CBD yield (p = 0.0002) per m2. Total area yields in the D-trial ranged from 119 to 247 g m-2 from lowest to highest PD. DVP showed a positive linear relationship with inflorescence yield on an individual plant (p = 0.0001) and area basis (p < 0.0001) along with most other relevant agronomic traits such as CBD production, plant size and lateral shoot length. Total area yields in the V-trial ranged from 295 to 571 g m-2 from lowest to highest DVP. The yield increase could be linked to the increased inflorescence number per plant rather than inflorescence size. In contrast to expectations, neither PD nor DVP had significant effects on the cannabinoid concentration gradient from upper to lower canopy layers. CBD concentrations in inflorescences from lower canopy layers were reduced by 23% in the V-trial and 46% in the D-trial. However, with increasing PD, the proportion of higher-concentrated inflorescence fractions from upper canopy layers increased from 46% to 68%, while an extension of DVP shifted this proportion only marginally from 45% to 50%. In the context of standardized production, we therefore advocate high-density production systems that increase the proportion of desired inflorescence fractions from upper canopy layers.
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Claims 16
Claim · model-written summary
An increase in plant density led to a linear decrease in inflorescence yield per plant
- Taxon
- medicinal cannabis (Cannabis sativa L.)
Cannabis sativae0 - Treatment
- increase in PDe1
- Outcome
- inflorescence yield per plante1
- Direction
- linear decreasee1
- Qualifier
- lineare1
- Setting
- greenhouse experimentse2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“An increase in PD led to a linear decrease in inflorescence yield per plant (p = 0.02)”
e2“We conducted two greenhouse experiments”
Claim · model-written summary
Plant density had a positive linear relationship with inflorescence yield per m2
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- PDe1
- Outcome
- inflorescence yielde2
- Direction
- positive linear relationshipe2
- Qualifier
- per m2e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“An increase in PD led to a linear decrease in inflorescence yield per plant (p = 0.02)”
e2“a positive linear relationship was found for inflorescence yield (p = 0.0001) and CBD yield (p = 0.0002) per m2”
Claim · model-written summary
Plant density had a positive linear relationship with CBD yield per m2
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- PDe1
- Outcome
- CBD yielde2
- Direction
- positive linear relationshipe2
- Qualifier
- per m2e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“An increase in PD led to a linear decrease in inflorescence yield per plant (p = 0.02)”
e2“a positive linear relationship was found for inflorescence yield (p = 0.0001) and CBD yield (p = 0.0002) per m2”
Claim · model-written summary
Total area yields in the D-trial ranged from 119 to 247 g m-2 across the plant density range
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Outcome
- Total area yielde1
- Value
- 119 to 247 g m-2e1
- Setting
- D-triale1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“Total area yields in the D-trial ranged from 119 to 247 g m-2 from lowest to highest PD”
Claim · model-written summary
Vegetative phase length had a positive linear relationship with inflorescence yield per individual plant
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- DVPe1
- Outcome
- inflorescence yield on an individual plante1
- Direction
- positive linear relationshipe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“DVP showed a positive linear relationship with inflorescence yield on an individual plant (p = 0.0001) and area basis (p < 0.0001)”
Claim · model-written summary
Vegetative phase length had a positive linear relationship with inflorescence yield per m2
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- DVPe1
- Outcome
- inflorescence yielde1
- Direction
- positive linear relationshipe1
- Qualifier
- area basise1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“DVP showed a positive linear relationship with inflorescence yield on an individual plant (p = 0.0001) and area basis (p < 0.0001)”
Claim · model-written summary
Vegetative phase length had a positive linear relationship with CBD production, plant size and lateral shoot length
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- DVPe1
- Outcome
- CBD production, plant size and lateral shoot lengthe2
- Direction
- positive linear relationshipe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“DVP showed a positive linear relationship with inflorescence yield on an individual plant (p = 0.0001) and area basis (p < 0.0001)”
e2“along with most other relevant agronomic traits such as CBD production, plant size and lateral shoot length”
Claim · model-written summary
Total area yields in the V-trial ranged from 295 to 571 g m-2 across the vegetative phase range
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Outcome
- Total area yieldse1
- Value
- 295 to 571 g m-2e1
- Setting
- V-triale1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“Total area yields in the V-trial ranged from 295 to 571 g m-2 from lowest to highest DVP”
Claim · model-written summary
The yield increase is linked to more inflorescences per plant rather than larger inflorescences
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Outcome
- yield increasee1
- Qualifier
- increased inflorescence number per plant rather than inflorescence sizee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“The yield increase could be linked to the increased inflorescence number per plant rather than inflorescence size”
Claim · model-written summary
Plant density had no significant effect on the cannabinoid concentration gradient from upper to lower canopy layers
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- PDe1
- Outcome
- cannabinoid concentration gradient from upper to lower canopy layerse1
- Direction
- no_changeinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“neither PD nor DVP had significant effects on the cannabinoid concentration gradient from upper to lower canopy layers”
Claim · model-written summary
Vegetative phase length had no significant effect on the cannabinoid concentration gradient from upper to lower canopy layers
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- DVPe1
- Outcome
- cannabinoid concentration gradient from upper to lower canopy layerse1
- Direction
- no_changeinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“neither PD nor DVP had significant effects on the cannabinoid concentration gradient from upper to lower canopy layers”
Claim · model-written summary
CBD concentrations in inflorescences from lower canopy layers were 23% lower in the V-trial
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Organ / stage
- lower canopy layerse1
- Outcome
- CBD concentrations in inflorescencese1
- Direction
- reducede1
- Value
- 23%e1
- Setting
- V-triale1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“CBD concentrations in inflorescences from lower canopy layers were reduced by 23% in the V-trial and 46% in the D-trial”
Claim · model-written summary
CBD concentrations in inflorescences from lower canopy layers were 46% lower in the D-trial
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Organ / stage
- lower canopy layerse1
- Outcome
- CBD concentrations in inflorescencese1
- Direction
- reducede1
- Value
- 46%e1
- Setting
- D-triale1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“CBD concentrations in inflorescences from lower canopy layers were reduced by 23% in the V-trial and 46% in the D-trial”
Claim · model-written summary
Increasing plant density increased the proportion of higher-concentrated inflorescence fractions from upper canopy layers from 46% to 68%
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- increasing PDe1
- Outcome
- proportion of higher-concentrated inflorescence fractions from upper canopy layerse1
- Direction
- increasede1
- Value
- from 46% to 68%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“with increasing PD, the proportion of higher-concentrated inflorescence fractions from upper canopy layers increased from 46% to 68%”
Claim · model-written summary
Extending the vegetative phase shifted the proportion of higher-concentrated upper canopy inflorescence fractions only marginally, from 45% to 50%
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- extension of DVPe2
- Outcome
- proportion of higher-concentrated inflorescence fractions from upper canopy layerse1
- Direction
- only marginallye2
- Value
- from 45% to 50%e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“with increasing PD, the proportion of higher-concentrated inflorescence fractions from upper canopy layers increased from 46% to 68%”
e2“an extension of DVP shifted this proportion only marginally from 45% to 50%”
Claim · model-written summary
High-density production systems are advocated to increase the proportion of desired upper canopy inflorescence fractions
- Taxon
- medicinal cannabis (Cannabis sativa L.)Cannabis sativae0
- Treatment
- high-density production systemse1
- Outcome
- proportion of desired inflorescence fractions from upper canopy layerse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“medicinal cannabis (Cannabis sativa L.)”
e1“we therefore advocate high-density production systems that increase the proportion of desired inflorescence fractions from upper canopy layers”
The same questions in other papers
density · growth · Cannabis sativaPositive and negative results
3 papers in the same direction as this paper · 2 in the opposite direction
- negative
- no effect
- positive
2 papers more in this group
See all 6 papers →density · yield · Cannabis sativaPositive and negative results
1 paper in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- positive
5 papers more in this group
See all 9 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.