Abstract
Practices to promote tree root growth have been sought in arboriculture for many years, especially as a treatment for trees that are stressed or in decline. Tree fertilization is a common practice in arboriculture. A few research reports have shown that nitrogen fertilization can increase fine-root density in localized areas of soil where the fertilizer has been applied, but the effect on the whole root system has not been investigated. Research has reported fine-root stimulating effects from basal application of the growth regulator paclobutrazol, but results have not been consistent. More information is needed. A slow-release granular formulation of nitrogen was broadcast over the entire root system of mature oaks for four consecutive years, with or without a paclobutrazol basal drench in the first year. Nitrogen was also applied to younger green ash and black maple as granular broadcast or subsoil liquid soil injection for two consecutive years. There was no overall increase in fine-root development from any of the treatments, and no localized increase from soil injection application of nitrogen. Growth response of the crowns was minimal. Soil profiles were undisturbed with moderate natural nitrogen availability. The results suggest that routine fertilization of trees at standard recommended rates may be ineffective if soil fertility is moderate.
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Claims 5
Claim · model-written summary
Soil-applied slow-release nitrogen produced no overall increase in fine-root development of mature oaks.
- Taxon
- mature oakse1
- Treatment
- A slow-release granular formulation of nitrogene1
- Outcome
- fine-root developmente2
- Direction
- no overall increasee2
Not reportedComparator
Verbatim
e1“A slow-release granular formulation of nitrogen was broadcast over the entire root system of mature oaks for four consecutive years, with or without a paclobutrazol basal drench in the first year”
e2“There was no overall increase in fine-root development from any of the treatments, and no localized increase from soil injection application of nitrogen”
Claim · model-written summary
Paclobutrazol basal drench produced no overall increase in fine-root development of mature oaks.
- Taxon
- mature oakse1
- Treatment
- paclobutrazol basal drenche1
- Outcome
- fine-root developmente2
- Direction
- no overall increasee2
Not reportedComparator
Verbatim
e1“A slow-release granular formulation of nitrogen was broadcast over the entire root system of mature oaks for four consecutive years, with or without a paclobutrazol basal drench in the first year”
e2“There was no overall increase in fine-root development from any of the treatments, and no localized increase from soil injection application of nitrogen”
Claim · model-written summary
Subsoil liquid soil injection of nitrogen produced no localized increase in fine-root development of green ash and black maple.
- Taxon
- green ash and black maple
Fraxinus pennsylvanica
Acer saccharum subsp. nigrume3 - Treatment
- soil injection application of nitrogene2
- Outcome
- fine-root developmente2
- Direction
- no localized increasee2
- Qualifier
- localizede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“There was no overall increase in fine-root development from any of the treatments, and no localized increase from soil injection application of nitrogen”
e3“Nitrogen was also applied to younger green ash and black maple as granular broadcast or subsoil liquid soil injection for two consecutive years”
Claim · model-written summary
Growth response of the crowns of trees was minimal.
Verbatim
e3“Growth response of the crowns was minimal”
e5“The results suggest that routine fertilization of trees at standard recommended rates may be ineffective if soil fertility is moderate”
Claim · model-written summary
Routine fertilization of trees at standard recommended rates may be ineffective if soil fertility is moderate.
Verbatim
e5“The results suggest that routine fertilization of trees at standard recommended rates may be ineffective if soil fertility is moderate”
The same questions in other papers
application · growth · QuercusPositive and negative results
1 in the opposite direction
- positive
application · growth · Fraxinus pennsylvanica (green ash)Positive and negative results
1 in the opposite direction
- positive
application · growth · Acer saccharum (sugar maple)Positive and negative results
1 in the opposite direction
- positive
nitrogen · growth · Acer saccharum (sugar maple)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
nitrogen · growth · QuercusPositive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
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.