Abstract
Controlled-release urea (CRU) can improve nitrogen (N) use efficiency and yield, but comprehensive evaluations of its agronomic, physiological, and environmental impacts remain limited. Through a two-year field experiment comparing three CRU types with conventional urea at five N rates (0-280 kg N ha−1), we demonstrate that CRU at 180 kg N ha−1 maintained high maize yields (13.9 Mg ha−1) while improving N use efficiency, with thermosetting polymer-coated samples (TCU) showing superior performance. There was a significant increase in the net photosynthetic rate by 7.9–32.7% and intercellular CO2 concentration by 20.6–40.0% under CRU treatments during the silking and milking stages. The CRU treatments also sustained optimal levels of hormones, N metabolism enzymes, and sucrase and urease activities. Compared to common urea, life cycle assessment indicates that CRU has achieved a 47.5% reduction in reactive N losses and an 18.7% decrease in greenhouse gas emissions. Economically, CRU outperformed common urea, with TCU providing the highest net benefit through yield stability and labor savings. These findings establish TCU at 180 kg N ha−1 as an optimal strategy of maize production in the North China Plain, balancing productivity, profitability, and environmental protection.
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Claims 11
Claim · model-written summary
CRU at 180 kg N ha−1 maintained maize yield at 13.9 Mg ha−1.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CRU at 180 kg N ha−1 maintained high maize yields (13.9 Mg ha−1) while improving N use efficiency”
Claim · model-written summary
CRU at 180 kg N ha−1 improved nitrogen use efficiency.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CRU at 180 kg N ha−1 maintained high maize yields (13.9 Mg ha−1) while improving N use efficiency”
Claim · model-written summary
TCU performed best among the coated urea samples.
- Material
- thermosetting polymer-coated samples (TCU)e0
- Outcome
- superior performancee0
- Direction
- superiore0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“thermosetting polymer-coated samples (TCU) showing superior performance”
t0“Maize Physiology”
Claim · model-written summary
CRU significantly increased net photosynthetic rate by 7.9–32.7% during silking and milking.
- Organ / stage
- silking and milking stagese0
- Treatment
- CRU treatmentse0
- Outcome
- net photosynthetic ratee0
- Direction
- increasee0
- Value
- 7.9–32.7%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increase in the net photosynthetic rate by 7.9–32.7% and intercellular CO2 concentration by 20.6–40.0% under CRU treatments during the silking and milking stages”
t0“Maize Physiology”
Claim · model-written summary
CRU significantly increased intercellular CO2 concentration by 20.6–40.0%.
- Organ / stage
- silking and milking stagese0
- Treatment
- CRU treatmentse0
- Outcome
- intercellular CO2 concentratione0
- Direction
- increasee0
- Value
- 20.6–40.0%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increase in the net photosynthetic rate by 7.9–32.7% and intercellular CO2 concentration by 20.6–40.0% under CRU treatments during the silking and milking stages”
t0“Maize Physiology”
Claim · model-written summary
CRU sustained optimal hormone levels, N metabolism enzymes, and sucrase and urease activities.
- Treatment
- CRU treatmentse0
- Outcome
- optimal levels of hormones, N metabolism enzymes, and sucrase and urease activitiese0
- Direction
- sustainede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CRU treatments also sustained optimal levels of hormones, N metabolism enzymes, and sucrase and urease activities”
t0“Maize Physiology”
Claim · model-written summary
CRU reduced reactive N losses by 47.5% relative to common urea.
Not reportedTaxon
Verbatim
e0“Compared to common urea, life cycle assessment indicates that CRU has achieved a 47.5% reduction in reactive N losses”
Claim · model-written summary
CRU decreased greenhouse gas emissions by 18.7% relative to common urea.
- Treatment
- CRUe0
- Outcome
- greenhouse gas emissionse0
- Direction
- decreasee0
- Value
- 18.7%e0
- Comparator
- common ureae0
Not reportedTaxon
Verbatim
e0“Compared to common urea, life cycle assessment indicates that CRU has achieved a 47.5% reduction in reactive N losses and an 18.7% decrease in greenhouse gas emissions”
Claim · model-written summary
CRU outperformed common urea economically.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Economically, CRU outperformed common urea”
t0“Maize Physiology”
Claim · model-written summary
TCU provided the highest net benefit through yield stability and labor savings.
- Treatment
- TCUe0
- Outcome
- net benefite0
- Direction
- higheste0
- Qualifier
- through yield stability and labor savingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“TCU providing the highest net benefit through yield stability and labor savings”
t0“Maize Physiology”
Claim · model-written summary
The authors identify TCU at 180 kg N ha−1 as an optimal maize production strategy in the North China Plain.
- Treatment
- TCU at 180 kg N ha−1e0
- Outcome
- optimal strategy of maize productione0
- Setting
- North China Plaine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“TCU at 180 kg N ha−1 as an optimal strategy of maize production in the North China Plain”
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