Abstract
Abstract Switchgrass ( Panicum virgatum L.) has been the principal perennial herbaceous crop investigated for bioenergy production in North America given its high production potential, relatively low input requirements, and potential suitability for use on marginal lands. Few large trials have determined switchgrass yields at field scale on marginal lands, including analysis of production costs. Thus, a field‐scale study was conducted to develop realistic yield and cost estimates for diverse regions of the USA . Objectives included measuring switchgrass response to fertility treatments (0, 56, and 112 kg N ha −1 ) and generating corresponding estimates of production costs for sites with diverse soil and climatic conditions. Trials occurred in Iowa, New York, Oklahoma, South Dakota, and Virginia, USA . Cultivars and management practices were site specific, and field‐scale equipment was used for all management practices. Input costs were estimated using final harvest‐year (2015) prices, and equipment operation costs were estimated with the MachData model ($2015). Switchgrass yields generally were below those reported elsewhere, averaging 6.3 Mg ha −1 across sites and treatments. Establishment stand percent ranged from 28% to 76% and was linked to initial year production. No response to N was observed at any site in the first production year. In subsequent seasons, N generally increased yields on well‐drained soils; however, responses to N were nil or negative on less well‐drained soils. Greatest percent increases in response to 112 kg N ha −1 were 57% and 76% on well‐drained South Dakota and Virginia sites, where breakeven prices to justify N applications were over $70 and $63 Mg −1 , respectively. For some sites, typically promoted N application rates may be economically unjustified; it remains unknown whether a bioenergy industry can support the breakeven prices estimated for sites where N inputs had positive effects on switchgrass yield.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 11
Claim · model-written summary
Switchgrass yield averaged 6.3 Mg per ha across sites and treatments.
- Taxon
- Switchgrass
Panicum virgatume0 - Outcome
- Switchgrass yieldse0
- Direction
- belowe0
- Value
- 6.3 Mg ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Switchgrass yields generally were below those reported elsewhere, averaging 6.3 Mg ha −1 across sites and treatments”
Claim · model-written summary
Establishment stands ranged from 28% to 76%.
- Taxon
- SwitchgrassPanicum virgatumt0
- Outcome
- Establishment stand percente0
- Value
- 28% to 76%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Establishment stand percent ranged from 28% to 76%”
t0“Switchgrass”
Claim · model-written summary
Establishment stand percentage was linked to initial year production.
- Taxon
- SwitchgrassPanicum virgatumt0
- Material
- Establishment stand percente0
- Outcome
- initial year productione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Establishment stand percent ranged from 28% to 76% and was linked to initial year production”
t0“Switchgrass”
Claim · model-written summary
Nitrogen gave no yield response at any site in the first production year.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- Ne0
- Outcome
- response to Ne0
- Direction
- No responsee0
- Qualifier
- first production yeare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No response to N was observed at any site in the first production year”
t0“Switchgrass”
Claim · model-written summary
Nitrogen generally increased yields on well-drained soils in later seasons.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- Ne0
- Outcome
- yieldse0
- Direction
- increasede0
- Qualifier
- well‐drained soilse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In subsequent seasons, N generally increased yields on well‐drained soils”
t0“Switchgrass”
Claim · model-written summary
Nitrogen responses were nil or negative on less well-drained soils.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- Ne0
- Outcome
- responses to Ne0
- Direction
- nil or negativee0
- Qualifier
- less well‐drained soilse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“responses to N were nil or negative on less well‐drained soils”
t0“Switchgrass”
Claim · model-written summary
At the South Dakota site, 112 kg N per ha increased yield 57%.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- 112 kg N ha −1e0
- Outcome
- percent increasese0
- Direction
- increasese0
- Value
- 57%e0
- Setting
- South Dakotae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Greatest percent increases in response to 112 kg N ha −1 were 57% and 76% on well‐drained South Dakota and Virginia sites”
t0“Switchgrass”
Claim · model-written summary
At the Virginia site, 112 kg N per ha increased yield 76%.
- Taxon
- SwitchgrassPanicum virgatumt0
- Treatment
- 112 kg N ha −1e0
- Outcome
- percent increasese0
- Direction
- increasese0
- Value
- 76%e0
- Setting
- Virginiae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Greatest percent increases in response to 112 kg N ha −1 were 57% and 76% on well‐drained South Dakota and Virginia sites”
t0“Switchgrass”
Claim · model-written summary
South Dakota required a breakeven price over $70 per Mg to justify nitrogen.
- Taxon
- SwitchgrassPanicum virgatumt0
- Outcome
- breakeven prices to justify N applicationse0
- Value
- $70e0
- Setting
- South Dakotae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“where breakeven prices to justify N applications were over $70 and $63 Mg −1 , respectively”
e1“South Dakota and Virginia sites”
t0“Switchgrass”
Claim · model-written summary
Virginia required a breakeven price over $63 per Mg to justify nitrogen.
- Taxon
- SwitchgrassPanicum virgatumt0
- Outcome
- breakeven prices to justify N applicationse0
- Value
- $63 Mg −1e0
- Setting
- Virginiae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“where breakeven prices to justify N applications were over $70 and $63 Mg −1 , respectively”
e1“South Dakota and Virginia sites”
t0“Switchgrass”
Claim · model-written summary
Promoted N rates may be uneconomic at some sites.
- Taxon
- SwitchgrassPanicum virgatumt0
- Outcome
- typically promoted N application rates may be economically unjustifiede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For some sites, typically promoted N application rates may be economically unjustified”
t0“Switchgrass”
The same questions in other papers
nitrogen · yield · Panicum virgatum (switchgrass)Results differ
22 papers in the same direction as this paper · 6 in the opposite direction
- no effect
- positive
- positive
25 papers more in this group
See all 29 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.