Abstract
Amino acid‐based products have been used as alternative fertilizer nitrogen (N) sources to improve turfgrass performance, especially where there is a strong reliance on synthetic N sources. However, the physiological mechanisms underlying improvements in turfgrass performance are not well documented. The objective of this research was to determine whether applications of a tryptophan‐containing organic byproduct (TRP‐B) or tryptophan (TRP) + urea improve creeping bentgrass ( Agrostis stolonifera L.) performance compared with standalone applications of urea, a commonly used synthetic N source. At two separate universities, mature ‘A‐4’ creeping bentgrass plugs were transplanted into containers and allowed to re‐establish in growth chambers before being treated. Treatments included TRP‐B, urea, and TRP + urea applied every 14 d at three different N rates: 2.5, 12.25, and 24.5 kg N ha −1 . At the trial's end, TRP‐B and TRP + urea increased leaf indole‐3‐acetic acid (IAA) by 227 and 255%, respectively, relative to urea at the high N rate, as measured at day 42 of the study. Applications of TRP‐B and TRP + urea also increased root biomass by 22 and 20%, respectively, when compared with urea only at the high N rate. The TRP‐B and TRP + urea treatments did not impact leaf total amino acids or photochemical efficiency when compared with urea only. Overall, results indicate that application of TRP‐B or TRP + urea at 24.5 kg N ha −1 every 2 wk may improve leaf and root IAA content, root biomass, and subsequent creeping bentgrass quality relative to applications of urea only.
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Claims 6
Claim · model-written summary
TRP-B increased leaf indole-3-acetic acid (IAA) by 227% relative to urea at the high N rate.
- Taxon
- Creeping Bentgrass
Agrostis stoloniferat0 - Organ / stage
- leafe1
- Treatment
- TRP‐Be1
- Outcome
- indole‐3‐acetic acid (IAA)e1
- Direction
- increasede1
- Value
- 227e1
- Comparator
- urea at the high N ratee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Creeping Bentgrass (Agrostis stolonifera L.)”
e1“TRP‐B and TRP + urea increased leaf indole‐3‐acetic acid (IAA) by 227 and 255%, respectively, relative to urea at the high N rate”
Claim · model-written summary
TRP + urea increased leaf indole-3-acetic acid (IAA) by 255% relative to urea at the high N rate.
- Taxon
- Creeping BentgrassAgrostis stoloniferat0
- Organ / stage
- leafe1
- Treatment
- TRP + ureae1
- Outcome
- indole‐3‐acetic acid (IAA)e1
- Direction
- increasede1
- Value
- 255e1
- Comparator
- urea at the high N ratee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Creeping Bentgrass (Agrostis stolonifera L.)”
e1“TRP‐B and TRP + urea increased leaf indole‐3‐acetic acid (IAA) by 227 and 255%, respectively, relative to urea at the high N rate”
Claim · model-written summary
TRP-B increased root biomass by 22% relative to urea only at the high N rate.
- Taxon
- Creeping BentgrassAgrostis stoloniferat0
- Organ / stage
- roote2
- Treatment
- TRP‐Be2
- Outcome
- root biomasse2
- Direction
- increasede2
- Value
- 22e2
- Comparator
- urea onlye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Creeping Bentgrass (Agrostis stolonifera L.)”
e2“Applications of TRP‐B and TRP + urea also increased root biomass by 22 and 20%, respectively, when compared with urea only at the high N rate”
Claim · model-written summary
TRP + urea increased root biomass by 20% relative to urea only at the high N rate.
- Taxon
- Creeping BentgrassAgrostis stoloniferat0
- Organ / stage
- roote2
- Treatment
- TRP + ureae2
- Outcome
- root biomasse2
- Direction
- increasede2
- Value
- 20e2
- Comparator
- urea onlye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Creeping Bentgrass (Agrostis stolonifera L.)”
e2“Applications of TRP‐B and TRP + urea also increased root biomass by 22 and 20%, respectively, when compared with urea only at the high N rate”
Claim · model-written summary
TRP-B and TRP + urea did not impact leaf total amino acids or photochemical efficiency compared with urea only.
- Taxon
- Creeping BentgrassAgrostis stoloniferat0
- Organ / stage
- leafe3
- Treatment
- TRP‐B and TRP + ureae3
- Outcome
- leaf total amino acids or photochemical efficiencye3
- Direction
- did not impacte3
- Comparator
- urea onlye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Creeping Bentgrass (Agrostis stolonifera L.)”
e3“The TRP‐B and TRP + urea treatments did not impact leaf total amino acids or photochemical efficiency when compared with urea only”
Claim · model-written summary
Applying TRP-B or TRP + urea at 24.5 kg N ha-1 every 2 wk may improve creeping bentgrass quality relative to urea only.
- Taxon
- Creeping BentgrassAgrostis stoloniferat0
- Organ / stage
- leaf and roote4
- Treatment
- application of TRP‐B or TRP + urea at 24.5 kg N ha −1 every 2 wke4
- Outcome
- creeping bentgrass qualitye4
- Comparator
- urea onlye4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Creeping Bentgrass (Agrostis stolonifera L.)”
e4“application of TRP‐B or TRP + urea at 24.5 kg N ha −1 every 2 wk may improve leaf and root IAA content, root biomass, and subsequent creeping bentgrass quality relative to applications of urea only”
The same questions in other papers
nitrogen · growth · Agrostis stolonifera (creeping bent grass)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
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.