Abstract
An ecosystem management model was used to project total aboveground and belowground production in hybrid poplar plantations for two sites in Saskatchewan that were previously in agricultural production and that differed in their soil organic matter and nitrogen content (categorized as poor and rich sites). Stemwood production (the primary measure of treatment response) was always negatively affected by the competition that resulted when weeds were abundant; the effect was more severe on the poor than on the rich site. Stemwood biomass was greater when weed competition was low, but peak production declined over successive rotations on both sites, regardless of whether fertilizer was used. Fertilization always enhanced stemwood production but less so on the rich than on the poor site. A single fertilizer application in the second or seventh year after plantation establishment resulted in consistently higher stemwood production than midrotation fertilization (year 12). Fertilization was more beneficial to stemwood production when weed competition was high than when it was low. Low weed competition in conjunction with early fertilization produced the highest stemwood production. The simulations indicate that the relative benefit of a given management regime cannot be considered independently of the site nutrient status and the particular rotation.
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The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
Abundant weeds reduced projected stemwood production, more severely on the poor site.
- Interactor
- weedse0weed
- Outcome
- Stemwood productione0
- Direction
- negatively affectede0
- Comparator
- rich sitee0
- Setting
- poore0
PopulusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“Stemwood production (the primary measure of treatment response) was always negatively affected by the competition that resulted when weeds were abundant; the effect was more severe on the poor than on the rich site.”
Claim · model-written summary
Low weed competition increased stemwood biomass.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“Stemwood biomass was greater when weed competition was low”
Claim · model-written summary
Peak stemwood production declined over successive rotations on both sites regardless of fertilizer.
- Outcome
- peak productione0
- Direction
- declinede0
- Qualifier
- over successive rotations on both sites, regardless of whether fertilizer was usede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“peak production declined over successive rotations on both sites, regardless of whether fertilizer was used”
Claim · model-written summary
Fertilization enhanced stemwood production, less on the rich site than the poor site.
- Treatment
- Fertilizatione0
- Outcome
- stemwood productione0
- Direction
- enhancede0
- Comparator
- poor sitee0
- Setting
- riche0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“Fertilization always enhanced stemwood production but less so on the rich than on the poor site.”
Claim · model-written summary
Fertilizer in year two or seven produced more stemwood than year twelve fertilization.
- Treatment
- A single fertilizer application in the second or seventh yeare0
- Outcome
- stemwood productione0
- Direction
- highere0
- Comparator
- midrotation fertilization (year 12)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“A single fertilizer application in the second or seventh year after plantation establishment resulted in consistently higher stemwood production than midrotation fertilization (year 12).”
Claim · model-written summary
Fertilization benefited stemwood production more under high weed competition.
- Treatment
- Fertilizatione0
- Interactor
- weede0weed
- Outcome
- stemwood productione0
- Direction
- more beneficiale0
- Comparator
- when it was lowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“Fertilization was more beneficial to stemwood production when weed competition was high than when it was low.”
Claim · model-written summary
Low weed competition with early fertilization gave the highest stemwood production.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“Low weed competition in conjunction with early fertilization produced the highest stemwood production.”
Claim · model-written summary
The relative benefit of management depended on site nutrient status and rotation.
- Outcome
- relative benefit of a given management regimee0
- Qualifier
- particular rotatione0
- Setting
- site nutrient statuse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“hybrid poplar plantations”
e0“The simulations indicate that the relative benefit of a given management regime cannot be considered independently of the site nutrient status and the particular rotation.”
The same questions in other papers
fertilization · yield · Populus (poplar)Results differ
10 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- no effect
- no effect
10 papers more in this group
See all 14 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.