Abstract
Unreasonably high irrigation levels and excessive nitrogen (N) supplementation are common occurrences in the North China Plain that affect winter wheat production. Therefore, a 6-yr-long stationary field experiment was conducted to investigate the effects of irrigation and N regimes on root development and their relationship with soil water and N use in different soil layers. Compared to the non-irrigated treatment (W0), a single irrigation at jointing (W1) significantly increased yield by 3.6-45.6%. With increases in water (W2, a second irrigation at flowering), grain yield was significantly improved by 14.1-45.3% compared to the W1 treatments during the drier growing seasons (2010-2011, 2012-2013, and 2015-2016). However, under sufficient pre-sowing soil moisture conditions, grain yield was not increased, and water use efficiency (WUE) decreased significantly in the W2 treatments during normal precipitation seasons (2011-2012, 2013-2014, and 2014-2015). Irrigating the soil twice inhibited root growth into the deeper soil depth profiles and thus weakened the utilization of soil water and NO3-N from the deep soil layers. N applications increased yield by 19.1-64.5%, with a corresponding increase in WUE of 66.9-83.9% compared to the no-N treatment (N0). However, there was no further increase in grain yield and the WUE response when N rates exceeded 240 kg N ha-1 and 180 kg N ha-1, respectively. A N application rate of 240 kg ha-1 facilitated root growth in the deep soil layers, which was conducive to utilization of soil water and NO3-N and also in reducing the residual NO3-N. Correlation analysis indicated that the grain yield was significantly positively correlated with soil water storage (SWS) and nitrate nitrogen accumulation (SNA) prior to sowing. Therefore, N rates of 180-240 kg ha-1 with two irrigations can reduce the risk of yield loss that occurs due to reduced precipitation during the wheat growing seasons, while under better soil moisture conditions, a single irrigation at jointing was effective and more economical.
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Claims 17
Claim · model-written summary
One irrigation at jointing increased wheat yield compared with no irrigation.
- Taxon
- Wheat
Triticum aestivumt0 - Treatment
- a single irrigation at jointing (W1)e0
- Outcome
- yielde0
- Direction
- increasede0
- Value
- 3.6-45.6%e0
- Comparator
- non-irrigated treatment (W0)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the non-irrigated treatment (W0), a single irrigation at jointing (W1) significantly increased yield by 3.6-45.6%.”
t0“Wheat”
Claim · model-written summary
A second irrigation at flowering increased grain yield in drier seasons compared with one irrigation.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- W2, a second irrigation at floweringe0
- Outcome
- grain yielde0
- Direction
- improvede0
- Value
- 14.1-45.3%e0
- Qualifier
- during the drier growing seasonse0
- Comparator
- W1 treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With increases in water (W2, a second irrigation at flowering), grain yield was significantly improved by 14.1-45.3% compared to the W1 treatments during the drier growing seasons (2010-2011, 2012-2013, and 2015-2016).”
t0“Wheat”
Claim · model-written summary
Two irrigations did not increase grain yield under sufficient pre-sowing moisture in normal precipitation seasons.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- W2 treatmentse1
- Outcome
- grain yielde0
- Direction
- not increasede0
- Qualifier
- under sufficient pre-sowing soil moisture conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“under sufficient pre-sowing soil moisture conditions, grain yield was not increased”
e1“in the W2 treatments during normal precipitation seasons”
t0“Wheat”
Claim · model-written summary
Two irrigations significantly reduced water use efficiency in normal precipitation seasons.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- W2 treatmentse0
- Outcome
- water use efficiency (WUE)e0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“water use efficiency (WUE) decreased significantly in the W2 treatments during normal precipitation seasons”
t0“Wheat”
Claim · model-written summary
Two irrigations inhibited root growth into deeper soil layers.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Irrigating the soil twicee0
- Outcome
- root growth into the deeper soil depth profilese0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irrigating the soil twice inhibited root growth into the deeper soil depth profiles”
t0“Wheat”
Claim · model-written summary
Two irrigations weakened use of soil water and nitrate nitrogen from deep layers.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Irrigating the soil twicee0
- Outcome
- utilization of soil water and NO3-N from the deep soil layerse0
- Direction
- weakenede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irrigating the soil twice inhibited root growth into the deeper soil depth profiles and thus weakened the utilization of soil water and NO3-N from the deep soil layers.”
t0“Wheat”
Claim · model-written summary
Nitrogen application increased wheat yield compared with no nitrogen.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- N applicationse0
- Outcome
- yielde0
- Direction
- increasede0
- Value
- 19.1-64.5%e0
- Comparator
- no-N treatment (N0)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N applications increased yield by 19.1-64.5%, with a corresponding increase in WUE of 66.9-83.9% compared to the no-N treatment (N0).”
t0“Wheat”
Claim · model-written summary
Nitrogen application increased wheat water use efficiency compared with no nitrogen.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- N applicationse0
- Outcome
- WUEe0
- Direction
- increasee0
- Value
- 66.9-83.9%e0
- Comparator
- no-N treatment (N0)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N applications increased yield by 19.1-64.5%, with a corresponding increase in WUE of 66.9-83.9% compared to the no-N treatment (N0).”
t0“Wheat”
Claim · model-written summary
Wheat grain yield did not rise further above 240 kg N ha-1.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- N rates exceeded 240 kg N ha-1e0
- Outcome
- grain yielde0
- Direction
- no further increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no further increase in grain yield and the WUE response when N rates exceeded 240 kg N ha-1 and 180 kg N ha-1, respectively.”
t0“Wheat”
Claim · model-written summary
Wheat water use efficiency did not rise further above 180 kg N ha-1.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- N rates exceeded 240 kg N ha-1 and 180 kg N ha-1e0
- Outcome
- WUE responsee0
- Direction
- no further increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no further increase in grain yield and the WUE response when N rates exceeded 240 kg N ha-1 and 180 kg N ha-1, respectively.”
t0“Wheat”
Claim · model-written summary
Nitrogen at 240 kg ha-1 facilitated wheat root growth in deep soil.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- A N application rate of 240 kg ha-1e0
- Outcome
- root growth in the deep soil layerse0
- Direction
- facilitatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A N application rate of 240 kg ha-1 facilitated root growth in the deep soil layers”
t0“Wheat”
Claim · model-written summary
Nitrogen at 240 kg ha-1 facilitated deep soil water and nitrate nitrogen use.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- A N application rate of 240 kg ha-1e0
- Outcome
- utilization of soil water and NO3-Ne0
- Direction
- conducivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A N application rate of 240 kg ha-1 facilitated root growth in the deep soil layers, which was conducive to utilization of soil water and NO3-N”
t0“Wheat”
Claim · model-written summary
Nitrogen at 240 kg ha-1 reduced residual nitrate nitrogen.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- A N application rate of 240 kg ha-1e0
- Outcome
- residual NO3-Ne0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A N application rate of 240 kg ha-1 facilitated root growth in the deep soil layers, which was conducive to utilization of soil water and NO3-N and also in reducing the residual NO3-N.”
t0“Wheat”
Claim · model-written summary
Grain yield was significantly positively correlated with pre-sowing soil water storage.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- grain yielde0
- Direction
- positively correlatede0
- Qualifier
- soil water storage (SWS)e0
- Setting
- prior to sowinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the grain yield was significantly positively correlated with soil water storage (SWS) and nitrate nitrogen accumulation (SNA) prior to sowing.”
t0“Wheat”
Claim · model-written summary
Grain yield was significantly positively correlated with pre-sowing nitrate nitrogen accumulation.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- grain yielde0
- Direction
- positively correlatede0
- Qualifier
- nitrate nitrogen accumulation (SNA)e0
- Setting
- prior to sowinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the grain yield was significantly positively correlated with soil water storage (SWS) and nitrate nitrogen accumulation (SNA) prior to sowing.”
t0“Wheat”
Claim · model-written summary
The authors recommend 180-240 kg ha-1 nitrogen with two irrigations to reduce yield-loss risk in dry growing seasons.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- N rates of 180-240 kg ha-1 with two irrigationse0
- Qualifier
- reduced precipitation during the wheat growing seasonse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N rates of 180-240 kg ha-1 with two irrigations can reduce the risk of yield loss that occurs due to reduced precipitation during the wheat growing seasons”
t0“Wheat”
Claim · model-written summary
The authors recommend a single irrigation at jointing under better soil moisture conditions.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- a single irrigation at jointinge0
- Qualifier
- under better soil moisture conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“under better soil moisture conditions, a single irrigation at jointing was effective and more economical.”
t0“Wheat”
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