Abstract
Abstract Background : Blends of controlled‐release and slow‐release urea may help to synchronize N release from fertilizers and N uptake by maize to improve the plant nitrogen use efficiency. Aim : We aimed to investigate the effects of slow‐release urea and controlled‐release urea and their blends with uncoated urea to release N for maize uptake over time in comparison to urea and ammonium nitrate. Methods : The experiment was performed under greenhouse conditions, and the treatments consisted of conventional urea, ammonium nitrate, three controlled‐release ureas (Multicote 4M®, Nitrocote®, and polyurethane‐coated urea), one slow‐release urea, and mixtures of controlled‐ release urea and slow‐release urea with uncoated urea. These treatments were applied at concentrations of 0, 150, 300, and 450 mg N kg −1 of soil. We evaluated the dry mass, nitrogen accumulation in the shoots, agronomic efficiency index and applied nitrogen recovery after each of three maize croppings. Furthermore, we characterized the N release pattern of the controlled‐release ureas and their coating thicknesses by using scanning electron microscopy. Results : The N release curves showed that Multicote 4M®, Nitrocote® and urea + polyurethane reached 80% of the N released in water at 40°C at 36, 30, and 13 d after incubation. The highest cumulative nitrogen accumulation (1127.4 mg pot −1 ), agronomic efficiency index (122.3%), and applied nitrogen recovery (69.3%) occurred with ammonium nitrate, with a low residual effect of only 25.4% of the total N accumulated after 35 d of cultivation. The highest cumulative dry mass was produced when the maize was fertilized with a blend in which 40% of the N came from Nitrocote® (44.8 g pot −1 ). Conclusions : The results showed that ammonium nitrate is an important option as an N source, but it has no residual effect. Controlled‐ release ureas and their blends have a delayed N release and promote constant N uptake after 70 d. After 70 d, the applied N rates were also more important than the N fertilizer technologies. An adequate mixture of N fertilizers could be an interesting option to help synchronize N release and uptake by maize. Technologies involving urea blends could be an option to improve the nitrogen use efficiency in comparison to that obtained by using uncoated urea while decreasing costs in comparison with the application of 100% controlled‐release urea or slow‐release urea.
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Claims 9
Claim · model-written summary
Ammonium nitrate gave the highest cumulative maize nitrogen accumulation.
- Treatment
- ammonium nitratee0
- Outcome
- cumulative nitrogen accumulatione0
- Direction
- higheste0
- Value
- 1127.4 mg pot −1e0
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest cumulative nitrogen accumulation (1127.4 mg pot −1 ), agronomic efficiency index (122.3%), and applied nitrogen recovery (69.3%) occurred with ammonium nitrate”
e1“N uptake by maize”
Claim · model-written summary
Ammonium nitrate gave the highest agronomic efficiency index.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest cumulative nitrogen accumulation (1127.4 mg pot −1 ), agronomic efficiency index (122.3%), and applied nitrogen recovery (69.3%) occurred with ammonium nitrate”
e1“N uptake by maize”
Claim · model-written summary
Ammonium nitrate gave the highest applied nitrogen recovery.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest cumulative nitrogen accumulation (1127.4 mg pot −1 ), agronomic efficiency index (122.3%), and applied nitrogen recovery (69.3%) occurred with ammonium nitrate”
e1“N uptake by maize”
Claim · model-written summary
Ammonium nitrate had a low residual effect of 25.4% of total nitrogen accumulated after 35 days.
- Treatment
- ammonium nitratee1
- Outcome
- residual effecte0
- Direction
- lowe0
- Value
- 25.4%e0
- Qualifier
- after 35 d of cultivatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“with a low residual effect of only 25.4% of the total N accumulated after 35 d of cultivation”
e1“occurred with ammonium nitrate”
e2“N uptake by maize”
Claim · model-written summary
A blend with 40% of nitrogen from Nitrocote produced the highest cumulative maize dry mass.
- Treatment
- a blend in which 40% of the N came from Nitrocote®e0
- Outcome
- cumulative dry masse0
- Direction
- higheste0
- Value
- 44.8 g pot −1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest cumulative dry mass was produced when the maize was fertilized with a blend in which 40% of the N came from Nitrocote® (44.8 g pot −1 )”
Claim · model-written summary
Controlled release ureas and their blends delayed nitrogen release.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Controlled‐ release ureas and their blends have a delayed N release”
e1“N uptake by maize”
Claim · model-written summary
Controlled release ureas and their blends promoted constant nitrogen uptake after 70 days.
- Treatment
- Controlled‐ release ureas and their blendse0
- Outcome
- N uptakee0
- Direction
- constante0
- Qualifier
- after 70 de0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Controlled‐ release ureas and their blends have a delayed N release and promote constant N uptake after 70 d”
e1“N uptake by maize”
Claim · model-written summary
After 70 days, applied nitrogen rates were more important than fertilizer technologies.
- Outcome
- applied N rates were also more important than the N fertilizer technologiese0
- Qualifier
- After 70 de0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After 70 d, the applied N rates were also more important than the N fertilizer technologies”
e1“N uptake by maize”
Claim · model-written summary
The authors suggest nitrogen fertilizer blends could improve nitrogen use efficiency relative to uncoated urea.
- Outcome
- Technologies involving urea blends could be an option to improve the nitrogen use efficiencye0
- Comparator
- uncoated ureae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Technologies involving urea blends could be an option to improve the nitrogen use efficiency in comparison to that obtained by using uncoated urea”
e1“N uptake by maize”
The same questions in other papers
ammonium nitrate · nutrient: content · Zea mays (maize)Positive and negative results
10 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- negative
- positive
9 papers more in this group
See all 13 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.