Abstract
Long-term continuous cropping, excessive nitrogen input, and low nitrogen use efficiency are prevalent issues in wheat production in the Northwest Oasis irrigation area. This study examined the compensatory mechanism on grain yield and nitrogen utilization by reducing nitrogen input in wheat and multi-cropping of green manure after wheat harvest. The goal was to provide a theoretical basis for developing efficient wheat production technologies with reduced nitrogen input. This long-term field experiment, initiated in 2018, collected data from 2020 to 2022. The main plot included four green manures: multi-cropped common vetch mixed with hairy vetch (HCV), common vetch (CV), rapeseed (R), and fallow (F) after the previous wheat harvest. Subplots applied three nitrogen rates: the local conventional rate (N3, 180 kg hm-2), reduced by 20% (N2, 144 kg hm-2), and reduced by 40% (N1, 108 kg hm-2). Our results indicated that reducing conventional nitrogen by 20% and 40% significantly decreased both grain yield and nitrogen uptake. However, multi-cropped hairy vetch mixed with common vetch after wheat harvest could compensate for the yield and nitrogen uptake losses caused by a 40% nitrogen reduction. When combined with a 20% nitrogen reduction, grain yield and nitrogen uptake increased by 21.4% and 6.9%, respectively (P < 0.05). Additionally, this cropping pattern compensated for the decreased nitrogen use efficiency resulting from a 40% nitrogen reduction and, when combined with a 20% nitrogen reduction, enhanced nitrogen use efficiency by 13.4% (P < 0.05). The compensation mechanism was attributed to: (1) Under a 40% nitrogen reduction, multi-cropped hairy vetch mixed with common vetch compensated for nitrogen uptake rate, increased net nitrogen assimilation rate by 34.3% (P < 0.05), maintained nitrogen distribution in the ear, and enhanced the nitrogen transportation rate from the stem by 6.6% (P < 0.05). (2) Compared with fallow after wheat harvest and the conventional nitrogen application rate, multi-cropped hairy vetch mixed with common vetch under a 20% nitrogen reduction increased mean nitrogen uptake efficiency and net nitrogen assimilation rate by 7.2% and 34.1%, respectively (P < 0.05). It also improved nitrogen distribution in the ear from early filling to maturity stages by 6.7% (P < 0.05) and enhanced the contribution rate of nitrogen transportation from stem and leaf to ear by 17.8% and 8.9%, respectively (P < 0.05). Therefore, multi-cropped hairy vetch mixed with common vetch after wheat harvest is a viable measure to reduce nitrogen fertilizer input. When combined with a 20% nitrogen reduction, it can increase grain yield and nitrogen use efficiency in wheat by improving nitrogen uptake rate, net nitrogen assimilation rate, and the contribution rate of nitrogen transportation from leaf and stem to ear, thereby promoting nitrogen distribution in the ear in arid oasis irrigated areas.
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Claims 16
Claim · model-written summary
Reducing conventional nitrogen by 20% and 40% significantly decreased wheat grain yield and nitrogen uptake.
- Taxon
- wheat
Triticum aestivumt0 - Treatment
- reducing conventional nitrogen by 20% and 40%e1
- Outcome
- grain yield and nitrogen uptakee1
- Direction
- decreasede1
- Comparator
- conventional nitrogene1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“reducing conventional nitrogen by 20% and 40% significantly decreased both grain yield and nitrogen uptake”
t0“wheat”
Claim · model-written summary
Multi-cropped hairy vetch mixed with common vetch after wheat harvest could compensate for the yield and nitrogen uptake losses caused by a 40% nitrogen reduction in wheat.
- Taxon
- wheatTriticum aestivume1
- Treatment
- multi-cropped hairy vetch mixed with common vetch after wheat harveste1
- Outcome
- yield and nitrogen uptake lossese1
- Direction
- compensatee1
- Qualifier
- 40% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“multi-cropped hairy vetch mixed with common vetch after wheat harvest could compensate for the yield and nitrogen uptake losses caused by a 40% nitrogen reduction”
Claim · model-written summary
Combined with a 20% nitrogen reduction, the vetch mixture increased wheat grain yield by 21.4% (P < 0.05).
- Taxon
- wheatTriticum aestivume1
- Treatment
- multi-cropped hairy vetch mixed with common vetch after wheat harveste1
- Outcome
- grain yielde2
- Direction
- increasede2
- Value
- 21.4%e2
- Qualifier
- 20% nitrogen reductione2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“multi-cropped hairy vetch mixed with common vetch after wheat harvest could compensate for the yield and nitrogen uptake losses caused by a 40% nitrogen reduction”
e2“When combined with a 20% nitrogen reduction, grain yield and nitrogen uptake increased by 21.4% and 6.9%, respectively (P < 0.05)”
Claim · model-written summary
Combined with a 20% nitrogen reduction, the vetch mixture increased wheat nitrogen uptake by 6.9% (P < 0.05).
- Taxon
- wheatTriticum aestivume1
- Treatment
- multi-cropped hairy vetch mixed with common vetch after wheat harveste1
- Outcome
- nitrogen uptakee2
- Direction
- increasede2
- Value
- 6.9%e2
- Qualifier
- 20% nitrogen reductione2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“multi-cropped hairy vetch mixed with common vetch after wheat harvest could compensate for the yield and nitrogen uptake losses caused by a 40% nitrogen reduction”
e2“When combined with a 20% nitrogen reduction, grain yield and nitrogen uptake increased by 21.4% and 6.9%, respectively (P < 0.05)”
Claim · model-written summary
The multi-cropping pattern compensated for the decreased nitrogen use efficiency caused by a 40% nitrogen reduction in wheat.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- this cropping patterne1
- Outcome
- nitrogen use efficiencye1
- Direction
- compensatede1
- Qualifier
- 40% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“this cropping pattern compensated for the decreased nitrogen use efficiency resulting from a 40% nitrogen reduction”
t0“wheat”
Claim · model-written summary
Combined with a 20% nitrogen reduction, the multi-cropping pattern enhanced wheat nitrogen use efficiency by 13.4% (P < 0.05).
- Taxon
- wheatTriticum aestivumt0
- Treatment
- this cropping patterne1
- Outcome
- nitrogen use efficiencye1
- Direction
- enhancede1
- Value
- 13.4%e1
- Qualifier
- 20% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“this cropping pattern compensated for the decreased nitrogen use efficiency resulting from a 40% nitrogen reduction and, when combined with a 20% nitrogen reduction, enhanced nitrogen use efficiency by 13.4%”
t0“wheat”
Claim · model-written summary
Under a 40% nitrogen reduction, multi-cropped hairy vetch mixed with common vetch compensated for nitrogen uptake rate in wheat.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- multi-cropped hairy vetch mixed with common vetche1
- Outcome
- nitrogen uptake ratee1
- Direction
- compensatede1
- Qualifier
- Under a 40% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Under a 40% nitrogen reduction, multi-cropped hairy vetch mixed with common vetch compensated for nitrogen uptake rate, increased net nitrogen assimilation rate by 34.3%”
t0“wheat”
Claim · model-written summary
Under a 40% nitrogen reduction, the vetch mixture increased net nitrogen assimilation rate of wheat by 34.3% (P < 0.05).
- Taxon
- wheatTriticum aestivumt0
- Treatment
- multi-cropped hairy vetch mixed with common vetche1
- Outcome
- net nitrogen assimilation ratee1
- Direction
- increasede1
- Value
- 34.3%e1
- Qualifier
- Under a 40% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Under a 40% nitrogen reduction, multi-cropped hairy vetch mixed with common vetch compensated for nitrogen uptake rate, increased net nitrogen assimilation rate by 34.3%”
t0“wheat”
Claim · model-written summary
Under a 40% nitrogen reduction, the vetch mixture maintained nitrogen distribution in the ear of wheat.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- eare1
- Treatment
- multi-cropped hairy vetch mixed with common vetche1
- Outcome
- nitrogen distribution in the eare1
- Direction
- maintainede1
- Qualifier
- Under a 40% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Under a 40% nitrogen reduction, multi-cropped hairy vetch mixed with common vetch compensated for nitrogen uptake rate, increased net nitrogen assimilation rate by 34.3% (P < 0.05), maintained nitrogen distribution in the ear, and enhanced the nitrogen transportation rate from the stem by 6.6%”
t0“wheat”
Claim · model-written summary
Under a 40% nitrogen reduction, the vetch mixture enhanced the nitrogen transportation rate from the wheat stem by 6.6% (P < 0.05).
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- steme1
- Treatment
- multi-cropped hairy vetch mixed with common vetche1
- Outcome
- nitrogen transportation rate from the steme1
- Direction
- enhancede1
- Value
- 6.6%e1
- Qualifier
- Under a 40% nitrogen reductione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Under a 40% nitrogen reduction, multi-cropped hairy vetch mixed with common vetch compensated for nitrogen uptake rate, increased net nitrogen assimilation rate by 34.3% (P < 0.05), maintained nitrogen distribution in the ear, and enhanced the nitrogen transportation rate from the stem by 6.6%”
t0“wheat”
Claim · model-written summary
Under a 20% nitrogen reduction, the vetch mixture increased mean nitrogen uptake efficiency of wheat by 7.2% compared with fallow and conventional nitrogen (P < 0.05).
- Taxon
- wheatTriticum aestivumt0
- Treatment
- multi-cropped hairy vetch mixed with common vetch under a 20% nitrogen reductione1
- Outcome
- mean nitrogen uptake efficiencye1
- Direction
- increasede1
- Value
- 7.2%e1
- Comparator
- fallow after wheat harvest and the conventional nitrogen application ratee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Compared with fallow after wheat harvest and the conventional nitrogen application rate, multi-cropped hairy vetch mixed with common vetch under a 20% nitrogen reduction increased mean nitrogen uptake efficiency and net nitrogen assimilation rate by 7.2% and 34.1%”
t0“wheat”
Claim · model-written summary
Under a 20% nitrogen reduction, the vetch mixture increased net nitrogen assimilation rate of wheat by 34.1% compared with fallow and conventional nitrogen (P < 0.05).
- Taxon
- wheatTriticum aestivumt0
- Treatment
- multi-cropped hairy vetch mixed with common vetch under a 20% nitrogen reductione1
- Outcome
- net nitrogen assimilation ratee1
- Direction
- increasede1
- Value
- 34.1%e1
- Comparator
- fallow after wheat harvest and the conventional nitrogen application ratee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Compared with fallow after wheat harvest and the conventional nitrogen application rate, multi-cropped hairy vetch mixed with common vetch under a 20% nitrogen reduction increased mean nitrogen uptake efficiency and net nitrogen assimilation rate by 7.2% and 34.1%”
t0“wheat”
Claim · model-written summary
The vetch mixture under a 20% nitrogen reduction improved nitrogen distribution in the wheat ear from early filling to maturity stages by 6.7% (P < 0.05).
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- early filling to maturity stagese1
- Outcome
- nitrogen distribution in the eare1
- Direction
- improvede1
- Value
- 6.7%e1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“improved nitrogen distribution in the ear from early filling to maturity stages by 6.7%”
t0“wheat”
Claim · model-written summary
The vetch mixture under a 20% nitrogen reduction enhanced the contribution rate of nitrogen transportation from stem to ear by 17.8% in wheat.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- steme1
- Outcome
- contribution rate of nitrogen transportation from stem and leaf to eare1
- Direction
- enhancede1
- Value
- 17.8%e1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“enhanced the contribution rate of nitrogen transportation from stem and leaf to ear by 17.8% and 8.9%”
t0“wheat”
Claim · model-written summary
The vetch mixture under a 20% nitrogen reduction enhanced the contribution rate of nitrogen transportation from leaf to ear by 8.9% in wheat.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- leafe1
- Outcome
- contribution rate of nitrogen transportation from stem and leaf to eare1
- Direction
- enhancede1
- Value
- 8.9%e1
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“enhanced the contribution rate of nitrogen transportation from stem and leaf to ear by 17.8% and 8.9%”
t0“wheat”
Claim · model-written summary
The authors conclude that multi-cropped hairy vetch mixed with common vetch after wheat harvest is a viable measure to reduce nitrogen fertilizer input.
- Taxon
- wheatTriticum aestivume1
- Outcome
- viable measure to reduce nitrogen fertilizer inpute1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“multi-cropped hairy vetch mixed with common vetch after wheat harvest is a viable measure to reduce nitrogen fertilizer input”
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