Abstract
Increasing nitrogen (N) rate could accelerate the decomposition of crop residues, and then improve crop yield by increasing N availability of soil and N uptake of crops. However, it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate. This study seeks to assess the effects of N rate and plant density on cotton yield, N use efficiency, leaf senescence, soil inorganic N, and apparent N balance in cotton stubble return fields in Liaocheng, China, in 2016 and 2017. Three plant densities 5.25 (D5.25), 6.75 (D6.75) and 8.25 (D8.25) plants m−2 and five N rates 0 (N0), 105 (N105), 210 (N210), 315 (N315), and 420 (N420) kg ha−1 were investigated. Compared to the combination used by local farmers (D5.25N315), a 33.3% N reduction and a 28.6% increase in plant density (D6.75N210) can maintain high cotton yield, while a 66.7% N reduction at 6.75 plants m−2 (D6.75N105) can only achieve high yield in the first year. Biological yield increased with the increase of N rate and plant density, and the highest yield was obtained under 420 kg N ha−1 at 8.25 plants m−2 (D8.25N420) across the two years under investigation. Compared to D5.25N315, N agronomic efficiency (NAE) and N recovery efficiency (NRE) in D6.75N210 increased by 30.2 and 54.1%, respectively, and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%, respectively. Soil inorganic N decreased sharply under 105 kg N ha−1, but no change was found under 210 kg N ha−1 at 6.75 plants m−2. N deficit occurred under 105 kg N ha−1, but it did not occurr under 210 kg N ha−1 at 6.75 plants m−2. Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha−1 were higher than those under N rate of 0 or 105 kg N ha−1 at all three densities. The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.
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Claims 14
Claim · model-written summary
Plant density 6.75 per m2 with 210 kg N ha-1 can maintain high cotton yield compared with the local farmers combination.
- Taxon
- cotton
Gossypium hirsutumt0 - Treatment
- D6.75N210e1
- Outcome
- cotton yielde1
- Direction
- maintaine1
- Qualifier
- a 33.3% N reduction and a 28.6% increase in plant densitye1
- Comparator
- the combination used by local farmers (D5.25N315)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e1“Compared to the combination used by local farmers (D5.25N315), a 33.3% N reduction and a 28.6% increase in plant density (D6.75N210) can maintain high cotton yield”
Claim · model-written summary
Plant density 6.75 per m2 with 105 kg N ha-1 achieved high cotton yield only in the first year.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- D6.75N105e2
- Outcome
- high yielde2
- Qualifier
- in the first yeare2
- Comparator
- the combination used by local farmers (D5.25N315)e1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e1“Compared to the combination used by local farmers (D5.25N315), a 33.3% N reduction and a 28.6% increase in plant density (D6.75N210) can maintain high cotton yield”
e2“a 66.7% N reduction at 6.75 plants m−2 (D6.75N105) can only achieve high yield in the first year”
Claim · model-written summary
Biological yield of cotton increased with higher N rate and plant density.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- N rate and plant densitye3
- Outcome
- Biological yielde3
- Direction
- increasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e3“Biological yield increased with the increase of N rate and plant density”
Claim · model-written summary
The highest cotton yield was obtained under 420 kg N ha−1 at 8.25 plants m−2 across the two years.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 420 kg N ha−1 at 8.25 plants m−2e4
- Outcome
- highest yielde4
- Direction
- higheste4
- Qualifier
- across the two years under investigatione4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e4“the highest yield was obtained under 420 kg N ha−1 at 8.25 plants m−2 (D8.25N420) across the two years under investigation”
Claim · model-written summary
D6.75N210 increased N agronomic efficiency by 30.2 compared with D5.25N315.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- D6.75N210e5
- Outcome
- N agronomic efficiency (NAE)e5
- Direction
- increasede5
- Value
- 30.2e5
- Comparator
- D5.25N315e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e5“Compared to D5.25N315, N agronomic efficiency (NAE) and N recovery efficiency (NRE) in D6.75N210 increased by 30.2 and 54.1%, respectively”
Claim · model-written summary
D6.75N210 increased N recovery efficiency by 54.1% compared with D5.25N315.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- D6.75N210e5
- Outcome
- N recovery efficiency (NRE)e5
- Direction
- increasede5
- Value
- 54.1%e5
- Comparator
- D5.25N315e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e5“Compared to D5.25N315, N agronomic efficiency (NAE) and N recovery efficiency (NRE) in D6.75N210 increased by 30.2 and 54.1%, respectively”
Claim · model-written summary
D6.75N105 increased NAE by 104.8 compared with D5.25N315.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- D6.75N105e6
- Outcome
- NAEe6
- Direction
- increasede6
- Value
- 104.8e6
- Comparator
- D5.25N315e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e5“Compared to D5.25N315, N agronomic efficiency (NAE) and N recovery efficiency (NRE) in D6.75N210 increased by 30.2 and 54.1%, respectively”
e6“NAE and NRE in D6.75N105 increased by 104.8 and 88.1%, respectively”
Claim · model-written summary
D6.75N105 increased NRE by 88.1% compared with D5.25N315.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- D6.75N105e6
- Outcome
- NREe6
- Direction
- increasede6
- Value
- 88.1%e6
- Comparator
- D5.25N315e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e5“Compared to D5.25N315, N agronomic efficiency (NAE) and N recovery efficiency (NRE) in D6.75N210 increased by 30.2 and 54.1%, respectively”
e6“NAE and NRE in D6.75N105 increased by 104.8 and 88.1%, respectively”
Claim · model-written summary
Soil inorganic N decreased sharply under 105 kg N ha-1 in cotton stubble fields.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 105 kg N ha−1e7
- Outcome
- Soil inorganic Ne7
- Direction
- decreased sharplye7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e7“Soil inorganic N decreased sharply under 105 kg N ha−1, but no change was found under 210 kg N ha−1 at 6.75 plants m−2”
Claim · model-written summary
Soil inorganic N showed no change under 210 kg N ha-1 at 6.75 plants per m2.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 210 kg N ha−1 at 6.75 plants m−2e7
- Outcome
- Soil inorganic Ne7
- Direction
- no changee7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e7“Soil inorganic N decreased sharply under 105 kg N ha−1, but no change was found under 210 kg N ha−1 at 6.75 plants m−2”
Claim · model-written summary
N deficit occurred under 105 kg N ha-1 in cotton stubble fields.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 105 kg N ha−1e7
- Outcome
- N deficite7
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e7“N deficit occurred under 105 kg N ha−1, but it did not occurr under 210 kg N ha−1 at 6.75 plants m−2”
Claim · model-written summary
No N deficit occurred under 210 kg N ha-1 at 6.75 plants per m2.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 210 kg N ha−1 at 6.75 plants m−2e7
- Outcome
- N deficite7
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e7“N deficit occurred under 105 kg N ha−1, but it did not occurr under 210 kg N ha−1 at 6.75 plants m−2”
Claim · model-written summary
Net photosynthetic rate and leaf N concentration of cotton were higher under 210 to 420 kg N ha-1 than under 0 or 105 kg N ha-1 at all three densities.
- Taxon
- cottonGossypium hirsutumt0
- Organ / stage
- leavese6
- Treatment
- N rate ranging from 210 to 420 kg ha−1e6
- Outcome
- Net photosynthetic rate and N concentration of leavese6
- Direction
- highere6
- Qualifier
- at all three densitiese6
- Comparator
- N rate of 0 or 105 kg N ha−1e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e6“Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha−1 were higher than those under N rate of 0 or 105 kg N ha−1 at all three densities”
Claim · model-written summary
D6.75N210 is a superior combination for cotton stubble retaining fields in the Yellow River Valley and similar ecologies.
- Taxon
- cottonGossypium hirsutumt0
- Outcome
- superior combinatione5
- Setting
- Yellow River Valleye5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Effects of plant density and nitrogen rate on cotton yield”
e5“The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies”
The same questions in other papers
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- no effect
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285 papers in the same direction as this paper · 53 in the opposite direction · 4 reporting no difference from an alternative
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See all 343 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.