Abstract
SummaryThe recovery of nitrogen (N) by a crop and its subsequent use for production can potentially be increased by the split application of N. The significance of this strategy for onions was tested in seven field experiments on Dutch clay soils from 1991 to 1994. An experimental recommendation system consisting of split N application accounting for soil mineral N by replenishing the soil mineral N with fertilizer N up to a crop stage-dependent threshold value, was compared with the pre-sowing fixed N rate of 100 kg ha–1 which is the current recommendation to farmers in the Netherlands. The experimental recommendation system resulted in an average application rate of 72–110 kg N ha–1 for a three-way respectively two-way N splitting. A loss of yield was not observed. Reduction of the threshold values used in the experimental recommendation system could further reduce the total N rate without yield loss. As onion growth until the 3–4 leaf stage did not appear to be influenced by the N rate before sowing, a soil sampling before sowing can be omitted from the sampling scheme of the experimental recommendation system. N splitting did not affect the estimated N loss during the growing season, the residual N in soil or the apparent recovery rate of the N applied. However, these variables were significantly influenced by the total N rate, which indicated that N loss to the environment could only be decreased by either lowering the fixed N rate before sowing or lowering the threshold values of the experimental recommendation system. However, the latter can be advantageous because the soil mineralization in spring is taken into account thereby adjusting for possible spring N losses.
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Claims 8
Claim · model-written summary
The experimental recommendation system resulted in an average onion application rate of 72–110 kg N ha–1 for two- or three-way N splitting.
- Taxon
- onions
Allium cepat0 - Treatment
- experimental recommendation systeme0
- Outcome
- average application ratee0
- Value
- 72–110 kg N ha–1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e0“The experimental recommendation system resulted in an average application rate of 72–110 kg N ha–1 for a three-way respectively two-way N splitting”
Claim · model-written summary
The experimental recommendation system did not cause a loss of onion yield compared with the pre-sowing fixed N rate of 100 kg ha–1.
- Taxon
- onionsAllium cepat0
- Treatment
- experimental recommendation systeme0
- Outcome
- loss of yielde1
- Direction
- was not observede1
- Comparator
- pre-sowing fixed N rate of 100 kg ha–1e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e0“The experimental recommendation system resulted in an average application rate of 72–110 kg N ha–1 for a three-way respectively two-way N splitting”
e1“A loss of yield was not observed”
e2“compared with the pre-sowing fixed N rate of 100 kg ha–1 which is the current recommendation to farmers in the Netherlands”
Claim · model-written summary
Reducing the threshold values of the experimental recommendation system could further reduce the total N rate for onions without yield loss.
- Taxon
- onionsAllium cepat0
- Treatment
- Reduction of the threshold valuese3
- Outcome
- total N ratee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e3“Reduction of the threshold values used in the experimental recommendation system could further reduce the total N rate without yield loss”
Claim · model-written summary
N splitting did not affect the estimated N loss during the growing season, the residual N in soil or the apparent recovery rate of onion N.
- Taxon
- onionsAllium cepat0
- Treatment
- N splittinge4
- Outcome
- the estimated N loss during the growing season, the residual N in soil or the apparent recovery ratee4
- Direction
- did not affecte4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e4“N splitting did not affect the estimated N loss during the growing season, the residual N in soil or the apparent recovery rate of the N applied”
Claim · model-written summary
Total N rate significantly influenced the estimated N loss, residual N and apparent recovery rate of onion N.
- Taxon
- onionsAllium cepat0
- Treatment
- total N ratee5
- Outcome
- these variablese5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e5“these variables were significantly influenced by the total N rate”
Claim · model-written summary
N loss to the environment in onion production could only be decreased by lowering the fixed N rate before sowing or the threshold values.
- Taxon
- onionsAllium cepat0
- Treatment
- lowering the fixed N rate before sowing or lowering the threshold valuese6
- Outcome
- N loss to the environmente6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e6“N loss to the environment could only be decreased by either lowering the fixed N rate before sowing or lowering the threshold values”
Claim · model-written summary
A soil sampling before sowing can be omitted from the sampling scheme of the experimental recommendation system for onions.
- Taxon
- onionsAllium cepat0
- Treatment
- N rate before sowinge7
- Outcome
- soil sampling before sowinge7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e7“As onion growth until the 3–4 leaf stage did not appear to be influenced by the N rate before sowing, a soil sampling before sowing can be omitted from the sampling scheme of the experimental recommendation system”
Claim · model-written summary
Onion growth until the 3–4 leaf stage did not appear to be influenced by the N rate before sowing.
- Taxon
- onionsAllium cepat0
- Organ / stage
- 3–4 leaf stagee7
- Treatment
- N rate before sowinge7
- Outcome
- onion growth until the 3–4 leaf stagee7
- Direction
- did not appear to be influencede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spring-sown onions”
e7“As onion growth until the 3–4 leaf stage did not appear to be influenced by the N rate before sowing, a soil sampling before sowing can be omitted from the sampling scheme of the experimental recommendation system”
The same questions in other papers
nitrogen · growth · Allium cepa (onion)Results differ
9 papers in the same direction as this paper · 71 in the opposite direction
- positive
- positive
- positive
77 papers more in this group
See all 81 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.