Abstract
A closely spaced (1 x 1 m) cottonwood (Populus deltoides Bartr.) plantation was established to evaluate the effects of nutrient availability on fine root dynamics. Slow-release fertilizer (17:6:12 N,P,K plus micronutrients) was applied to 225-m(2) plots at 0, 50, 100 and 200 kg N ha(-1), and plots were monitored for two growing seasons. Fine root production, mortality, live root standing crop and life span were analyzed based on monthly minirhizotron observations. Fine root biomass was measured in soil cores. Fine root dynamics were controlled more by temporal, depth and root diameter factors than by fertilization. Cumulative fine root production and mortality showed strong seasonal patterns; production was greatest in the middle of the growing season and mortality was greatest after the growing season. Small diameter roots at shallow soil depths cycled more rapidly than larger or deeper roots. The strongest treatment effects were found in the most rapidly cycling roots. The standing crop of live roots increased with fertilizer treatment according to both minirhizotron and soil coring methods. However, production and mortality had unique treatment response patterns. Although cumulative mortality decreased in response to increased fertilization, cumulative production was intermediate at 0 kg N ha(-1), lowest with 50 kg N ha (-1), and highest with 200 kg N ha(-1). Aboveground growth responded positively to fertilization up to an application rate of 50 kg N ha(-1), but no further increases in growth were observed despite a threefold increase in application rate. Median fine root life span varied from 307 to over 700 days and increased with depth, diameter and nutrient availability.
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Claims 16
Claim · model-written summary
Temporal, soil depth and root diameter factors controlled fine root dynamics more than fertilization.
- Taxon
- Populus deltoides
Populus deltoidest0 - Outcome
- Fine root dynamicse0
- Direction
- moree0
- Qualifier
- temporal, depth and root diameter factorse0
- Comparator
- fertilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fine root dynamics were controlled more by temporal, depth and root diameter factors than by fertilization”
t0“Populus deltoides”
Claim · model-written summary
Fine root production peaked in the middle of the growing season.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Outcome
- productione0
- Direction
- greateste0
- Setting
- middle of the growing seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“production was greatest in the middle of the growing season”
t0“Populus deltoides”
Claim · model-written summary
Fine root mortality peaked after the growing season.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Outcome
- mortalitye0
- Direction
- greateste0
- Setting
- after the growing seasone0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mortality was greatest after the growing season”
t0“Populus deltoides”
Claim · model-written summary
Small shallow roots cycled more rapidly than larger or deeper roots.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Organ / stage
- Small diameter rootse0
- Outcome
- cyclede0
- Direction
- more rapidlye0
- Comparator
- larger or deeper rootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Small diameter roots at shallow soil depths cycled more rapidly than larger or deeper roots”
t0“Populus deltoides”
Claim · model-written summary
The strongest fertilization effects occurred in the most rapidly cycling roots.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Organ / stage
- most rapidly cycling rootse0
- Outcome
- treatment effectse0
- Direction
- strongeste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The strongest treatment effects were found in the most rapidly cycling roots”
t0“Populus deltoides”
Claim · model-written summary
Fertilization increased live root standing crop.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- fertilizer treatmente0
- Outcome
- standing crop of live rootse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The standing crop of live roots increased with fertilizer treatment according to both minirhizotron and soil coring methods”
t0“Populus deltoides”
Claim · model-written summary
Increasing fertilization decreased cumulative fine root mortality.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- increased fertilizatione0
- Outcome
- cumulative mortalitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cumulative mortality decreased in response to increased fertilization”
t0“Populus deltoides”
Claim · model-written summary
Cumulative fine root production was intermediate with no N fertilizer.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- 0 kg N ha(-1)e0
- Outcome
- cumulative productione0
- Direction
- intermediatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cumulative production was intermediate at 0 kg N ha(-1), lowest with 50 kg N ha (-1), and highest with 200 kg N ha(-1)”
t0“Populus deltoides”
Claim · model-written summary
Cumulative production was lowest at 50 kg N per hectare.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- 50 kg N ha (-1)e0
- Outcome
- cumulative productione0
- Direction
- loweste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cumulative production was intermediate at 0 kg N ha(-1), lowest with 50 kg N ha (-1), and highest with 200 kg N ha(-1)”
t0“Populus deltoides”
Claim · model-written summary
Cumulative production was highest at 200 kg N per hectare.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- 200 kg N ha(-1)e0
- Outcome
- cumulative productione0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cumulative production was intermediate at 0 kg N ha(-1), lowest with 50 kg N ha (-1), and highest with 200 kg N ha(-1)”
t0“Populus deltoides”
Claim · model-written summary
Aboveground growth rose with fertilizer up to 50 kg N per hectare.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- fertilization up to an application rate of 50 kg N ha(-1)e0
- Outcome
- Aboveground growthe0
- Direction
- positivelye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aboveground growth responded positively to fertilization up to an application rate of 50 kg N ha(-1)”
t0“Populus deltoides”
Claim · model-written summary
Higher fertilizer rates produced no further aboveground growth increase.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- threefold increase in application ratee0
- Outcome
- growthe0
- Direction
- no further increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no further increases in growth were observed despite a threefold increase in application rate”
t0“Populus deltoides”
Claim · model-written summary
Median fine root life span ranged from 307 to over 700 days.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Outcome
- Median fine root life spane0
- Value
- 307 to over 700 dayse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Median fine root life span varied from 307 to over 700 days”
t0“Populus deltoides”
Claim · model-written summary
Fine root life span increased with soil depth.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Outcome
- fine root life spane0
- Direction
- increasede0
- Setting
- depthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Median fine root life span varied from 307 to over 700 days and increased with depth, diameter and nutrient availability”
t0“Populus deltoides”
Claim · model-written summary
Fine root life span increased with diameter.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Organ / stage
- diametere0
- Outcome
- fine root life spane0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Median fine root life span varied from 307 to over 700 days and increased with depth, diameter and nutrient availability”
t0“Populus deltoides”
Claim · model-written summary
Fine root life span increased with nutrient availability.
- Taxon
- Populus deltoidesPopulus deltoidest0
- Treatment
- nutrient availabilitye0
- Outcome
- fine root life spane0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Median fine root life span varied from 307 to over 700 days and increased with depth, diameter and nutrient availability”
t0“Populus deltoides”
The same questions in other papers
nitrogen · growth · Populus deltoidesPositive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- negative
- positive
fertilization · growth · Populus deltoidesResults agree
5 papers in the same direction as this paper
- positive
- positive
- positive
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.