Abstract
Humic acids (HA) reportedly enhance the growth of numerous crops; however, little information is available as to their effects on turfgrasses. Experiments were conducted to evaluate the effect of a commercial preparation of HA on the photosynthesis, chlorophyll concentration, rooting, and nutrient content of `Crenshaw' creeping bentgrass ( Agrostis stolonifera L.). Bentgrass plugs were grown hydroponically in one-quarter-strength Hoagland's nutrient solution containing HA at 0, 100, 200, or 400 mg·L -1 with measurements made weekly for 1 month. The photosynthetic rates of plants growing in 100 or 200 mg·L -1 rarely differed from that of the control, but 400 mg·L -1 significantly enhanced net photosynthesis on all four observation dates. Chlorophyll content was unaffected by HA rate on all observation dates. Root dehydrogenase (DH) activity and root mass regrowth were significantly increased by HA at 400 mg·L -1 on all dates. The 100 and 200 mg·L -1 rates increased root DH activity on two of four observation dates, but root regrowth was unaffected. At one or more of the rates used, HA increased tissue concentrations of Mg, Mn, and S and decreased those of Ca, Cu, and N, but had no influence on the concentrations of P, K, Fe, Mo, and Zn.
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Claims 10
Claim · model-written summary
At 100 or 200 mg·L -1 humic acid, photosynthesis rarely differed from control.
- Taxon
- creeping bentgrass
Agrostis stoloniferat0 - Treatment
- 100 or 200 mg·L -1e0
- Outcome
- photosynthetic ratese0
- Direction
- rarely differede0
- Comparator
- controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rates of plants growing in 100 or 200 mg·L -1 rarely differed from that of the control”
t0“creeping bentgrass”
Claim · model-written summary
Humic acid at 400 mg·L -1 significantly enhanced net photosynthesis on all dates.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- 400 mg·L -1e0
- Outcome
- net photosynthesise0
- Direction
- enhancede0
- Qualifier
- all four observation datese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“400 mg·L -1 significantly enhanced net photosynthesis on all four observation dates”
t0“creeping bentgrass”
Claim · model-written summary
Chlorophyll content was unaffected by humic acid rate on all dates.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- HA ratee0
- Outcome
- Chlorophyll contente0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll content was unaffected by HA rate on all observation dates”
t0“creeping bentgrass”
Claim · model-written summary
Humic acid at 400 mg·L -1 increased root dehydrogenase activity on all dates.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- HA at 400 mg·L -1e0
- Outcome
- Root dehydrogenase (DH) activitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root dehydrogenase (DH) activity and root mass regrowth were significantly increased by HA at 400 mg·L -1 on all dates”
t0“creeping bentgrass”
Claim · model-written summary
Humic acid at 400 mg·L -1 increased root mass regrowth on all dates.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- HA at 400 mg·L -1e0
- Outcome
- root mass regrowthe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root dehydrogenase (DH) activity and root mass regrowth were significantly increased by HA at 400 mg·L -1 on all dates”
t0“creeping bentgrass”
Claim · model-written summary
Humic acid at 100 and 200 mg·L -1 increased root dehydrogenase activity on two dates.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- 100 and 200 mg·L -1e0
- Outcome
- root DH activitye0
- Direction
- increasede0
- Qualifier
- two of four observation datese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 100 and 200 mg·L -1 rates increased root DH activity on two of four observation dates”
t0“creeping bentgrass”
Claim · model-written summary
Humic acid at 100 and 200 mg·L -1 did not affect root regrowth.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- 100 and 200 mg·L -1e0
- Outcome
- root regrowthe0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The 100 and 200 mg·L -1 rates increased root DH activity on two of four observation dates, but root regrowth was unaffected”
t0“creeping bentgrass”
Claim · model-written summary
At one or more rates, humic acid increased tissue Mg, Mn and S concentrations.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
- Treatment
- HAe0
- Outcome
- tissue concentrations of Mg, Mn, and Se0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At one or more of the rates used, HA increased tissue concentrations of Mg, Mn, and S”
t0“creeping bentgrass”
Claim · model-written summary
At one or more rates, humic acid decreased tissue Ca, Cu and N concentrations.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased those of Ca, Cu, and N”
e1“At one or more of the rates used, HA increased tissue concentrations of Mg, Mn, and S and decreased those of Ca, Cu, and N”
t0“creeping bentgrass”
Claim · model-written summary
Humic acid did not affect tissue P, K, Fe, Mo and Zn concentrations.
- Taxon
- creeping bentgrassAgrostis stoloniferat0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“had no influence on the concentrations of P, K, Fe, Mo, and Zn”
e1“HA increased tissue concentrations of Mg, Mn, and S and decreased those of Ca, Cu, and N, but had no influence on the concentrations of P, K, Fe, Mo, and Zn”
t0“creeping bentgrass”
The same questions in other papers
other · physiology: pigments · Agrostis stolonifera (creeping bent grass)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
other · growth · Agrostis stolonifera (creeping bent grass)Positive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- positive
- positive
- no effect
1 paper more in this group
See all 5 papers →other · nutrient: content · Agrostis stolonifera (creeping bent grass)Positive and negative results
1 paper in the same direction as this paper · 3 in the opposite direction · 1 reporting no difference from an alternative
- no effect
- negative
- no effect
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.