Abstract
Controlled release fertilizers, especially polymer‐coated urea (PCU), have been shown to reduce nitrate (NO 3 ) leaching while maintaining potato ( Solanum tuberosum L.) yields, but cost has been prohibitive. A new type of PCU (Environmentally Smart Nitrogen, Agrium, Inc., Calgary, AB) is less costly than previous PCUs, but its effectiveness on potato production has not been extensively studied. A 2‐yr field study was conducted on loamy sand to evaluate the effect of this PCU on Russet Burbank tuber yield and to determine if it is economically comparable to soluble N sources. Several N rates of PCU applied at emergence were compared with two split applications of soluble N at equivalent rates. Additional treatments examined N application timing of PCU and a fertigation simulation with urea/ammonium nitrate. Petioles and midseason soil samples were collected to determine N status during the season. Overall, PCU and soluble N at equivalent N rates were found to have similar total and grade A yields and net monetary returns. The optimal N rate that resulted in maximum net returns was 251 and 236 kg N ha −1 as soluble N and PCU, respectively. Petiole NO 3 concentrations were typically higher with soluble N early in the season and higher with PCU later in the season. Soil NO 3 determined in samples collected in late June was found to be a better predictor of yield and potential N need than those collected in mid‐ to late July. Overall, PCU may reduce or eliminate the need for split applications of N on coarse‐textured soils.
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Claims 8
Claim · model-written summary
PCU and soluble nitrogen at equivalent rates yielded similarly in total and grade A tubers.
- Taxon
- Potato
Solanum tuberosumt0 - Treatment
- PCUe0
- Outcome
- total and grade A yieldse0
- Direction
- similare0
- Comparator
- soluble Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PCU and soluble N at equivalent N rates were found to have similar total and grade A yields”
t0“Potato”
Claim · model-written summary
PCU and soluble nitrogen produced similar net monetary returns.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- PCUe0
- Outcome
- net monetary returnse0
- Direction
- similare0
- Comparator
- soluble Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PCU and soluble N at equivalent N rates were found to have similar total and grade A yields and net monetary returns”
t0“Potato”
Claim · model-written summary
Maximum net return with soluble N occurred at 251 kg N ha−1.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- soluble Ne0
- Outcome
- maximum net returnse0
- Direction
- maximume0
- Value
- 251e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The optimal N rate that resulted in maximum net returns was 251 and 236 kg N ha −1 as soluble N and PCU, respectively”
t0“Potato”
Claim · model-written summary
Maximum net return with PCU occurred at 236 kg N ha−1.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- PCUe0
- Outcome
- maximum net returnse0
- Direction
- maximume0
- Value
- 236e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The optimal N rate that resulted in maximum net returns was 251 and 236 kg N ha −1 as soluble N and PCU, respectively”
t0“Potato”
Claim · model-written summary
Early-season petiole nitrate was typically higher with soluble N.
- Taxon
- PotatoSolanum tuberosumt0
- Organ / stage
- Petiolee0
- Treatment
- soluble Ne0
- Outcome
- Petiole NO 3 concentrationse0
- Direction
- highere0
- Qualifier
- early in the seasone0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Petiole NO 3 concentrations were typically higher with soluble N early in the season”
t0“Potato”
Claim · model-written summary
Later-season petiole nitrate was typically higher with PCU.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- PCUe0
- Outcome
- Petiole NO 3 concentrationse1
- Direction
- highere0
- Qualifier
- later in the seasone0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher with PCU later in the season”
t0“Potato”
e1“Petiole NO 3 concentrations”
Claim · model-written summary
Late-June soil nitrate predicted yield and nitrogen need better than mid-to-late-July samples.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- predictor of yield and potential N neede0
- Direction
- bettere0
- Comparator
- those collected in mid‐ to late Julye0
Not reportedSetting
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soil NO 3 determined in samples collected in late June was found to be a better predictor of yield and potential N need than those collected in mid‐ to late July”
t0“Potato”
Claim · model-written summary
Authors suggest PCU may reduce or eliminate split nitrogen applications on coarse soils.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- PCUe0
- Outcome
- reduce or eliminate the need for split applications of Ne0
- Qualifier
- coarse‐textured soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PCU may reduce or eliminate the need for split applications of N on coarse‐textured soils”
t0“Potato”
The same questions in other papers
nitrogen · yield · Solanum tuberosum (potato)Results differ
22 papers in the same direction as this paper · 109 in the opposite direction
- positive
- positive
- positive
128 papers more in this group
See all 132 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.