Abstract
Abstract Hemp ( Cannabis sativa L.) was recently re‐legalized in the United States and cultivated for various purposes, including floral cannabidiol (CBD), grain, and fiber. Due to prohibition of hemp for a century, research supporting production guidelines, including plant density effects on CBD production, remains limited. This study determined the responses of field‐grown full‐season CBD hemp cultivars to plant stand densities ranging from 4000 to 86,000 plants ha −1 from 2021 to 2023 in a semiarid, irrigated environment in Southern Oregon. Crop measurements included primary, secondary (2° colas) and tertiary floral (3° colas) biomass, Stem+Leaf biomass, cannabinoid concentration, and cannabinoid yield. Over an eightfold increase in stand density each year, plant morphology clearly changed. Stem+Leaf biomass per plant decreased by about fourfold, expressed as smaller plants having fewer side branches. The biomass of 2° colas decreased by about fivefold per plant, while 3° cola biomass also decreased to nearly zero at the highest densities. The primary flower size varied little with density. Since floral CBD concentration was almost constant at all stand densities, the CBD yield per hectare was controlled by the yield of floral material. While the per‐plant biomass of floral material decreased as density increased, the simultaneous increase in plant number per hectare resulted in an apparent CBD “yield plateau” at a density of about 50,000–60,000 plant ha −1 for Stella and about 70,000–80,000 plant ha −1 for Lifter. These were 10–15 times the densities commonly seen in production fields in southern Oregon.
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Claims 9
Claim · model-written summary
Stem+Leaf biomass per plant decreased by about fourfold as stand density increased in hemp.
- Taxon
- Hemp
Cannabis sativa subsp. sativae0 - Treatment
- stand densitye1
- Outcome
- Stem+Leaf biomass per plante1
- Direction
- decreasede1
- Value
- about fourfolde1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e1“Over an eightfold increase in stand density each year, plant morphology clearly changed. Stem+Leaf biomass per plant decreased by about fourfold, expressed as smaller plants having fewer side branches. The biomass of 2° colas decreased by about fivefold per plant, while 3° cola biomass also decreased to nearly zero at the highest densities.”
Claim · model-written summary
The biomass of 2° colas decreased by about fivefold per plant as stand density increased in hemp.
- Taxon
- HempCannabis sativa subsp. sativae0
- Treatment
- stand densitye1
- Outcome
- biomass of 2° colase1
- Direction
- decreasede1
- Value
- about fivefolde1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e1“Over an eightfold increase in stand density each year, plant morphology clearly changed. Stem+Leaf biomass per plant decreased by about fourfold, expressed as smaller plants having fewer side branches. The biomass of 2° colas decreased by about fivefold per plant, while 3° cola biomass also decreased to nearly zero at the highest densities.”
Claim · model-written summary
3° cola biomass decreased to nearly zero at the highest stand densities in hemp.
- Taxon
- HempCannabis sativa subsp. sativae0
- Treatment
- stand densitye1
- Outcome
- 3° cola biomasse1
- Direction
- decreasede1
- Value
- nearly zeroe1
- Qualifier
- at the highest densitiese1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e1“Over an eightfold increase in stand density each year, plant morphology clearly changed. Stem+Leaf biomass per plant decreased by about fourfold, expressed as smaller plants having fewer side branches. The biomass of 2° colas decreased by about fivefold per plant, while 3° cola biomass also decreased to nearly zero at the highest densities.”
Claim · model-written summary
Primary flower size varied little with plant density in hemp.
- Taxon
- HempCannabis sativa subsp. sativae0
- Treatment
- densitye3
- Outcome
- primary flower sizee3
- Direction
- no_changeinferrede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e3“The primary flower size varied little with density”
Claim · model-written summary
Floral CBD concentration was almost constant across all stand densities in hemp.
- Taxon
- HempCannabis sativa subsp. sativae0
- Treatment
- stand densitiese2
- Outcome
- floral CBD concentratione2
- Direction
- no_changeinferrede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e2“Since floral CBD concentration was almost constant at all stand densities, the CBD yield per hectare was controlled by the yield of floral material”
Claim · model-written summary
CBD yield per hectare was controlled by the yield of floral material in hemp.
- Taxon
- HempCannabis sativa subsp. sativae0
- Outcome
- CBD yield per hectaree2
- Qualifier
- controlled by the yield of floral materiale2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e2“Since floral CBD concentration was almost constant at all stand densities, the CBD yield per hectare was controlled by the yield of floral material”
Claim · model-written summary
CBD yield reached an apparent plateau at about 50,000–60,000 plants per hectare for Stella.
- Taxon
- HempCannabis sativa subsp. sativae0
- Material
- Stellae4
- Outcome
- yield plateaue4
- Value
- 50,000–60,000 plant ha −1e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e4“the simultaneous increase in plant number per hectare resulted in an apparent CBD “yield plateau” at a density of about 50,000–60,000 plant ha −1 for Stella and about 70,000–80,000 plant ha −1 for Lifter”
Claim · model-written summary
CBD yield reached an apparent plateau at about 70,000–80,000 plants per hectare for Lifter.
- Taxon
- HempCannabis sativa subsp. sativae0
- Material
- Liftere4
- Outcome
- yield plateaue4
- Value
- 70,000–80,000 plant ha −1e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e4“the simultaneous increase in plant number per hectare resulted in an apparent CBD “yield plateau” at a density of about 50,000–60,000 plant ha −1 for Stella and about 70,000–80,000 plant ha −1 for Lifter”
Claim · model-written summary
The yield plateau densities were 10–15 times the densities commonly seen in production fields in southern Oregon.
- Taxon
- HempCannabis sativa subsp. sativae0
- Outcome
- densitiese5
- Value
- 10–15 timese5
- Comparator
- densities commonly seen in production fieldse5
- Setting
- southern Oregone5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hemp ( Cannabis sativa L.)”
e5“These were 10–15 times the densities commonly seen in production fields in southern Oregon”
The same questions in other papers
density · molecular: metabolites · Cannabis sativaPositive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
- no effect
density · growth · Cannabis sativaPositive and negative results
1 paper in the same direction as this paper · 4 in the opposite direction
- positive
- positive
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2 papers more in this group
See all 6 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.