Abstract
Abstract Switchgrass ( Panicum virgatum L.) and Caucasian bluestem [ Bothriochloa caucasica (Trin.) C.E. Hubbard] provide forage during summer when cool‐season grasses in the southern Corn Belt are unproductive. Information is limited on the response of these grasses to defoliation, especially the effect of harvest management on regrowth. Field studies on a Creldon silt loam soil (fine, mixed, mesic Mollic Fragiudalf) were conducted to determine forage yield and quality trends and persistence of Switchgrass and Caucasian bluestem as influenced by date of first harvest and stubble height. Five dates of first harvest and two cutting heights (8 and 23 cm) were imposed factorially on established stands of Switchgrass and Caucasian bluestem for 3 years. The first harvests were taken consecutively at 1 week intervals with the initial first harvest made when plants were in a vegetative to early jointing growth stage. When cut at an 8 cm stubble height, first harvest yields of Switchgrass and Caucasian bluestem averaged over 3 years increased 763 and 1,010 kg/ha per week, respectively, with each week delay of first harvest. However, corresponding total regrowth yields/ha declined 424 kg for Switchgrass and 632 kg for Caucasian bluestem. Trends were similar for cutting at a stubble height of 23 cm, but yields were usually less than at 8 cm. Forage in vitro dry matter disappearance declined 2.0 percentage units per week for both Switchgrass and Caucasian bluestem while crude protein declined 1.6 and 1.0 percentage units per week, respectively, with each week delay in first harvest. Neutral detergent fiber (NDF) increased 1.4 percentage units per week for Caucasian bluestem at both stubble heights and for Switchgrass at 8 cm; the NDF of Switchgrass at 23 cm increased 0.4 percentage units per week. Our results indicated that Switchgrass and Caucasian bluestem should be harvested when plants begin to joint. Early harvest results in forage of higher quality and regrowth potential than harvest at later growth stages.
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Claims 13
Claim · model-written summary
Switchgrass first harvest yield increased 763 kg/ha per week of delay at 8 cm.
- Taxon
- Switchgrass
Panicum virgatume0 - Treatment
- each week delay of first harveste0
- Outcome
- first harvest yieldse0
- Direction
- increasede0
- Value
- 763e0
- Qualifier
- 8 cm stubble heighte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When cut at an 8 cm stubble height, first harvest yields of Switchgrass and Caucasian bluestem averaged over 3 years increased 763 and 1,010 kg/ha per week, respectively, with each week delay of first harvest.”
Claim · model-written summary
Caucasian bluestem first harvest yield increased 1,010 kg/ha per week of delay at 8 cm.
- Taxon
- Caucasian bluesteme0
- Treatment
- each week delay of first harveste0
- Outcome
- first harvest yieldse0
- Direction
- increasede0
- Value
- 1,010 kg/hae0
Not reportedComparator
Verbatim
e0“When cut at an 8 cm stubble height, first harvest yields of Switchgrass and Caucasian bluestem averaged over 3 years increased 763 and 1,010 kg/ha per week, respectively, with each week delay of first harvest.”
Claim · model-written summary
Switchgrass regrowth yield declined 424 kg per week of harvest delay.
- Taxon
- SwitchgrassPanicum virgatume0
- Outcome
- total regrowth yields/hae0
- Direction
- declinede0
- Value
- 424 kge0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, corresponding total regrowth yields/ha declined 424 kg for Switchgrass and 632 kg for Caucasian bluestem.”
Claim · model-written summary
Caucasian bluestem regrowth yield declined 632 kg per week of harvest delay.
Not reportedTreatmentComparator
Verbatim
e0“However, corresponding total regrowth yields/ha declined 424 kg for Switchgrass and 632 kg for Caucasian bluestem.”
Claim · model-written summary
Yields at 23 cm were usually lower than at 8 cm.
Not reportedTaxon
Verbatim
e0“Trends were similar for cutting at a stubble height of 23 cm, but yields were usually less than at 8 cm.”
Claim · model-written summary
Switchgrass forage dry matter disappearance declined 2.0 percentage units per week.
- Taxon
- SwitchgrassPanicum virgatume0
- Treatment
- each week delay in first harveste0
- Outcome
- Forage in vitro dry matter disappearancee0
- Direction
- declinede0
- Value
- 2.0 percentage units per weeke0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Forage in vitro dry matter disappearance declined 2.0 percentage units per week for both Switchgrass and Caucasian bluestem while crude protein declined 1.6 and 1.0 percentage units per week, respectively, with each week delay in first harvest.”
Claim · model-written summary
Caucasian bluestem forage dry matter disappearance declined 2.0 percentage units per week.
- Taxon
- Caucasian bluesteme0
- Treatment
- each week delay in first harveste0
- Outcome
- Forage in vitro dry matter disappearancee0
- Direction
- declinede0
- Value
- 2.0 percentage units per weeke0
Not reportedComparator
Verbatim
e0“Forage in vitro dry matter disappearance declined 2.0 percentage units per week for both Switchgrass and Caucasian bluestem while crude protein declined 1.6 and 1.0 percentage units per week, respectively, with each week delay in first harvest.”
Claim · model-written summary
Switchgrass crude protein declined 1.6 percentage units per week.
- Taxon
- SwitchgrassPanicum virgatume0
- Treatment
- each week delay in first harveste0
- Outcome
- crude proteine0
- Direction
- declinede0
- Value
- 1.6e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Forage in vitro dry matter disappearance declined 2.0 percentage units per week for both Switchgrass and Caucasian bluestem while crude protein declined 1.6 and 1.0 percentage units per week, respectively, with each week delay in first harvest.”
Claim · model-written summary
Caucasian bluestem crude protein declined 1.0 percentage units per week.
- Taxon
- Caucasian bluesteme0
- Treatment
- each week delay in first harveste0
- Outcome
- crude proteine0
- Direction
- declinede0
- Value
- 1.0 percentage units per weeke0
Not reportedComparator
Verbatim
e0“Forage in vitro dry matter disappearance declined 2.0 percentage units per week for both Switchgrass and Caucasian bluestem while crude protein declined 1.6 and 1.0 percentage units per week, respectively, with each week delay in first harvest.”
Claim · model-written summary
Caucasian bluestem NDF increased 1.4 percentage units per week at both stubble heights.
- Taxon
- Caucasian bluesteme0
- Outcome
- Neutral detergent fiber (NDF)e0
- Direction
- increasede0
- Value
- 1.4 percentage units per weeke0
Not reportedTreatmentComparator
Verbatim
e0“Neutral detergent fiber (NDF) increased 1.4 percentage units per week for Caucasian bluestem at both stubble heights and for Switchgrass at 8 cm; the NDF of Switchgrass at 23 cm increased 0.4 percentage units per week.”
Claim · model-written summary
Switchgrass NDF increased 1.4 percentage units per week at 8 cm.
- Taxon
- SwitchgrassPanicum virgatume0
- Outcome
- NDFe0
- Direction
- increasede0
- Value
- 1.4 percentage units per weeke0
- Qualifier
- 8 cme0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neutral detergent fiber (NDF) increased 1.4 percentage units per week for Caucasian bluestem at both stubble heights and for Switchgrass at 8 cm; the NDF of Switchgrass at 23 cm increased 0.4 percentage units per week.”
Claim · model-written summary
Switchgrass NDF increased 0.4 percentage units per week at 23 cm.
- Taxon
- SwitchgrassPanicum virgatume0
- Outcome
- NDFe0
- Direction
- increasede0
- Value
- 0.4 percentage units per weeke0
- Qualifier
- 23 cme0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neutral detergent fiber (NDF) increased 1.4 percentage units per week for Caucasian bluestem at both stubble heights and for Switchgrass at 8 cm; the NDF of Switchgrass at 23 cm increased 0.4 percentage units per week.”
Claim · model-written summary
The authors recommend harvesting switchgrass and Caucasian bluestem when plants begin to joint.
Verbatim
e0“Our results indicated that Switchgrass and Caucasian bluestem should be harvested when plants begin to joint.”
The same questions in other papers
pruning · yield · Panicum virgatum (switchgrass)Positive and negative results
7 papers in the same direction as this paper · 3 in the opposite direction
- positive
- negative
- positive
7 papers more in this group
See all 11 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.