Abstract
Abstract A 3‐yr study in northern Wisconsin measured the effects of ground cover treatments and N fertilization on tree growth, NO 3 − ‐N leaching, and N mineralization in an irrigated hybrid poplar ( Populus deltoides Bartr. × P. trichocarpa Torr. and Gray, clone NC‐9922) plantation. Annually fertilized (112 kg N/ha per year) and unfertilized plots were either maintained weed‐free (bare soil), allowed to revegetate with native weeds, or seeded to birdsfoot trefoil ( Lotus corniculatus L.). Soil solution NO 3 − ‐N was monitored in samples from permanently installed cup lysimeters. During the first two growing seasons, fertilization in bare soil plots increased NO 3 − ‐N concentrations below the rooting zone to over 150 mg N/L. Tree growth response to fertilization in these plots occurred primarily in the third growing season, and NO 3 − ‐N concentrations were much lower in and below the rooting zone relative to previous years. Fertilization increased NO 3 − ‐N concentrations in the rooting zone during growing seasons two through four in trefoil plots and three and four in native weed plots. Nitrate‐N concentrations below the rooting zone in all trefoil and native weed plots averaged ≤ 11 mg/L until the end of the fourth growing season when it averaged 20 to 24 mg/L in fertilized plots. Fertilization significantly increased soil N mineralization in buried plastic bags only in plots with a ground cover and was 42 to 47% greater in these plots compared with fertilized bare soil plots. This study indicates that ground cover plays an important role in preventing leaching losses of fertilizer and native soil N in young biomass plantations.
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Claims 10
Claim · model-written summary
Fertilization in bare soil plots increased soil NO3-N concentrations below the rooting zone to over 150 mg N/L during the first two growing seasons.
- Treatment
- Annually fertilized (112 kg N/ha per year)e4
- Outcome
- concentrations below the rooting zonee2
- Direction
- increasede1
- Value
- over 150 mg N/Le2
- Qualifier
- During the first two growing seasonse3
- Comparator
- unfertilized plotse5
- Setting
- northern Wisconsine6
PopulusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e1“fertilization in bare soil plots increased”
e2“concentrations below the rooting zone to over 150 mg N/L”
e3“During the first two growing seasons”
e4“Annually fertilized (112 kg N/ha per year)”
e5“and unfertilized plots were either maintained”
e6“in northern Wisconsin”
Claim · model-written summary
Tree growth response to fertilization occurred primarily in the third growing season of the hybrid poplar plantation.
- Treatment
- fertilizatione6
- Outcome
- Tree growth responsee6
- Direction
- increaseinferrede6
- Qualifier
- primarily in the third growing seasone6
- Comparator
- unfertilized plotse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e6“Tree growth response to fertilization in these plots occurred primarily in the third growing season”
e5“and unfertilized plots were either maintained”
Claim · model-written summary
In the third growing season, NO3-N concentrations below and within the rooting zone of fertilized poplar plots were much lower than in previous years.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e6“Tree growth response to fertilization in these plots occurred primarily in the third growing season”
e7“concentrations were much lower in and below the rooting zone relative to previous years”
Claim · model-written summary
Fertilization increased NO3-N concentrations in the rooting zone of trefoil plots during growing seasons two through four.
- Treatment
- Fertilizatione6
- Outcome
- concentrations in the rooting zonee7
- Direction
- increasede6
- Qualifier
- during growing seasons two through foure7
- Comparator
- unfertilized plotse5
- Setting
- trefoil plotse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e6“Fertilization increased”
e7“concentrations in the rooting zone during growing seasons two through four in trefoil plots”
e5“and unfertilized plots were either maintained”
Claim · model-written summary
Fertilization increased NO3-N concentrations in the rooting zone of native weed plots in growing seasons three and four.
- Treatment
- Fertilizatione6
- Outcome
- concentrations in the rooting zonee7
- Direction
- increasede6
- Qualifier
- three and foure1
- Comparator
- unfertilized plotse5
- Setting
- native weed plotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e6“Fertilization increased”
e7“concentrations in the rooting zone during growing seasons two through four in trefoil plots”
e1“three and four in native weed plots”
e5“and unfertilized plots were either maintained”
Claim · model-written summary
In trefoil and native weed plots, NO3-N concentrations below the rooting zone averaged 11 mg/L or less until the end of the fourth growing season.
- Outcome
- concentrations below the rooting zonee1
- Value
- ≤ 11 mg/Le1
- Qualifier
- until the end of the fourth growing seasone1
- Setting
- trefoil and native weed plotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e1“concentrations below the rooting zone in all trefoil and native weed plots averaged ≤ 11 mg/L until the end of the fourth growing season when it averaged 20 to 24 mg/L in fertilized plots”
Claim · model-written summary
In fertilized plots, NO3-N concentrations below the rooting zone averaged 20 to 24 mg/L at the end of the fourth growing season, higher than in unfertilized plots.
- Treatment
- fertilizede1
- Outcome
- concentrations below the rooting zonee1
- Direction
- higherinferrede1
- Value
- 20 to 24 mg/Le1
- Comparator
- unfertilized plotse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e1“concentrations below the rooting zone in all trefoil and native weed plots averaged ≤ 11 mg/L until the end of the fourth growing season when it averaged 20 to 24 mg/L in fertilized plots”
e5“and unfertilized plots were either maintained”
Claim · model-written summary
Fertilization significantly increased soil N mineralization in buried bags only in plots with a ground cover.
- Treatment
- Fertilizatione1
- Outcome
- soil N mineralizatione1
- Direction
- increasede1
- Qualifier
- only in plots with a ground covere1
- Comparator
- unfertilized plotse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e1“Fertilization significantly increased soil N mineralization in buried plastic bags only in plots with a ground cover”
e5“and unfertilized plots were either maintained”
Claim · model-written summary
Soil N mineralization in ground cover plots was 42 to 47% greater than in fertilized bare soil plots.
- Treatment
- ground covere1
- Outcome
- soil N mineralizatione1
- Direction
- greatere2
- Value
- 42 to 47%e2
- Comparator
- fertilized bare soil plotse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e1“Fertilization significantly increased soil N mineralization in buried plastic bags only in plots with a ground cover”
e2“was 42 to 47% greater in these plots compared with fertilized bare soil plots”
Claim · model-written summary
Ground cover plays an important role in preventing leaching losses of fertilizer and native soil N in young poplar plantations, compared with bare soil.
- Treatment
- ground covere2
- Outcome
- preventing leaching losses of fertilizer and native soil Ne2
- Direction
- preventinge2
- Comparator
- bare soile1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in an irrigated hybrid poplar”
e2“This study indicates that ground cover plays an important role in preventing leaching losses of fertilizer and native soil N in young biomass plantations”
e1“fertilization in bare soil plots increased”
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fertilization · growth · Populus (poplar)Results differ
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See all 23 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.