Abstract
Golf course putting greens are evaluated based on aesthetic qualities and playability. Cultural practices such as nitrogen (N) fertility and the use of plant growth regulators (PGRs) can influence both quality and the visual aesthetic of a putting green surface. The objectives of this research were to assess the effects of 1) N rate and the combination of trinexapac-ethyl, paclobutrazol, and flurprimidol on the playability and turfgrass quality of creeping bentgrass (Agrostis stolonifera cv ‘777’), and 2) N rate and the combination of trinexapac-ethyl, paclobutrazol, and flurprimidol on the severity of the disease commonly referred to as dollar spot, caused by the fungus (Clarireedia jacksonii) on a research putting green in north-central Oklahoma. Nitrogen application treatments included five rates (0, 4.9, 9.8, 14.7, 19.5 kg ha⁻¹ N per application) arranged in factorial with three rates of (0.9, 1.3, 1.6 L ha⁻¹ per application) a mixture of trinexapac-ethyl (1.4%), paclobutrazol (5.6%), and flurprimidol (5.6%). Applications were made every 14 days for 20 weeks starting 1st May 2021 and 2022. Golf ball roll distance (BRD) was measured using a Stimpmeter at 7 and 14 days after each N and PGR application. Visual turfgrass quality (TQ) ratings, normalized difference vegetation index (NDVI), normalized difference red edge (NDRE), and dark green color index (DGCI) were measured weekly to quantify aesthetic quality. Visual dollar spot disease incidence and digital image analysis (DIA) were used to assess dollar spot disease severity. For TQ, NDVI, and NDRE the N treated plots had higher ratings than the non-fertilized plots. Plots receiving PGR had significantly lower NDVI than the non-regulated plots. In 2021, the 0 and 4.9 kg ha⁻¹ N plots resulted in greater BRD than the other three N rates, while a similar pattern was found in 2022. The use of PGR did not influence BRD in 2021, but the highest rate increased BRD in 2022. In 2021, the high N rate (19.5 kg ha⁻¹ N) reduced disease incidence, while in 2022 plots receiving N had reduced disease compared the 0 N rate. Visual disease was also decreased by PGR applications. For each year, average dollar spot size and diameter were decreased by using the high N rate (19.5 kg ha⁻¹ N). Plots treated with PGR had less dollar spot disease than the non-regulated plots. Increasing N resulted in lower BRD but improved turfgrass quality. Both increasing N rates and the use of PGR decreased dollar spot severity and increased turfgrass quality.
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Claims 14
Claim · model-written summary
Nitrogen raised turf quality, NDVI and NDRE relative to unfertilized plots.
- Taxon
- creeping bentgrass
Agrostis stoloniferat0 - Treatment
- N treatede0
- Outcome
- TQ, NDVI, and NDREe0
- Direction
- highere0
- Comparator
- non-fertilized plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For TQ, NDVI, and NDRE the N treated plots had higher ratings than the non-fertilized plots”
t0“creeping bentgrass”
Claim · model-written summary
Growth regulators significantly reduced NDVI.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- PGRe0
- Outcome
- NDVIe0
- Direction
- lowere0
- Comparator
- non-regulated plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plots receiving PGR had significantly lower NDVI than the non-regulated plots”
t0“creeping bentgrass”
Claim · model-written summary
Low nitrogen rates produced greater ball roll distance in 2021.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- 0 and 4.9 kg ha⁻¹ Ne0
- Outcome
- BRDe0
- Direction
- greatere0
- Qualifier
- 2021e0
- Comparator
- other three N ratese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2021, the 0 and 4.9 kg ha⁻¹ N plots resulted in greater BRD than the other three N rates”
t0“creeping bentgrass”
Claim · model-written summary
The low nitrogen rate pattern for ball roll distance recurred in 2022.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Outcome
- similar patterne0
- Qualifier
- 2022e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while a similar pattern was found in 2022”
t0“creeping bentgrass”
Claim · model-written summary
Growth regulators did not change ball roll distance in 2021.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- PGRe0
- Outcome
- BRDe0
- Direction
- did not influencee0
- Qualifier
- 2021e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The use of PGR did not influence BRD in 2021”
t0“creeping bentgrass”
Claim · model-written summary
The highest growth regulator rate increased ball roll distance in 2022.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- highest ratee0
- Outcome
- BRDe0
- Direction
- increasede0
- Qualifier
- 2022e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the highest rate increased BRD in 2022”
t0“creeping bentgrass”
Claim · model-written summary
High nitrogen reduced dollar spot incidence in 2021.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- high N rate (19.5 kg ha⁻¹ N)e0
- Interactor
- Clarireedia jacksoniiClarireedia jacksoniie1pathogent0
- Outcome
- disease incidencee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2021, the high N rate (19.5 kg ha⁻¹ N) reduced disease incidence”
e1“caused by the fungus (Clarireedia jacksonii)”
t0“creeping bentgrass”
Claim · model-written summary
Nitrogen reduced disease versus zero nitrogen in 2022.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- receiving Ne0
- Interactor
- Clarireedia jacksoniiClarireedia jacksoniie1pathogent0
- Outcome
- diseasee0
- Direction
- reducede0
- Comparator
- 0 N ratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in 2022 plots receiving N had reduced disease compared the 0 N rate”
e1“caused by the fungus (Clarireedia jacksonii)”
t0“creeping bentgrass”
Claim · model-written summary
Growth regulator applications decreased visual disease.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- PGR applicationse0
- Interactor
- Clarireedia jacksoniiClarireedia jacksoniie1pathogent0
- Outcome
- Visual diseasee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Visual disease was also decreased by PGR applications”
e1“caused by the fungus (Clarireedia jacksonii)”
t0“creeping bentgrass”
Claim · model-written summary
High nitrogen decreased average dollar spot size and diameter in both years.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- high N rate (19.5 kg ha⁻¹ N)e0
- Interactor
- Clarireedia jacksoniiClarireedia jacksoniie1pathogent0
- Outcome
- average dollar spot size and diametere0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For each year, average dollar spot size and diameter were decreased by using the high N rate (19.5 kg ha⁻¹ N)”
e1“caused by the fungus (Clarireedia jacksonii)”
t0“creeping bentgrass”
Claim · model-written summary
Growth regulator plots had less dollar spot than non-regulated plots.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- PGRe0
- Interactor
- Clarireedia jacksoniiClarireedia jacksoniie1pathogent0
- Outcome
- dollar spot diseasee0
- Direction
- lesse0
- Comparator
- non-regulated plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plots treated with PGR had less dollar spot disease than the non-regulated plots”
e1“caused by the fungus (Clarireedia jacksonii)”
t0“creeping bentgrass”
Claim · model-written summary
Increasing nitrogen lowered ball roll distance.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- Increasing Ne0
- Outcome
- BRDe0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing N resulted in lower BRD but improved turfgrass quality”
t0“creeping bentgrass”
Claim · model-written summary
Increasing nitrogen improved turfgrass quality.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- Increasing Ne0
- Outcome
- turfgrass qualitye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing N resulted in lower BRD but improved turfgrass quality”
t0“creeping bentgrass”
Claim · model-written summary
Growth regulators increased turfgrass quality.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- PGRe0
- Outcome
- turfgrass qualitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the use of PGR decreased dollar spot severity and increased turfgrass quality”
t0“creeping bentgrass”
The same questions in other papers
class · growth · Agrostis stolonifera (creeping bent grass)Positive and negative results
2 in the opposite direction
- positive
- positive
class · quality: general · Agrostis stolonifera (creeping bent grass)Results agree
1 paper in the same direction as this paper
- 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.