Abstract
Abstract Due to an increased demand for excluding external nitrogen fertilization there is a need for cultivation measures which optimize use of legume nitrogen fixation. We have, during field conditions in central Sweden, evaluated the contribution of intercropped peas (Pisum sativum L.) and oats (Avena sativa L.) to the overall N economy. We have done this by determining the N2 fixation by the difference method and by the 15N-dilution method using two reference crops. N2 fixing efficiency was calculated as fixed nitrogen of total pea nitrogen and of dry matter, respectively. We complemented this by determining the mineral nitrogen at three soil levels before and after the growing seasons. Our results indicate that nitrogen yield sometimes, but not dry matter yield, was affected by pea ratio. The efficiency of the fixation increased with decreasing pea ratio. This could be explained by competition for N from the intercropped oats, in which the N-concentration decreased with decreasing pea ratio. Results indicate that peas supplied the intercropped oats with nitrogen. Residual soil mineral nitrogen after harvest was similar in the intercrop to the pure stand of oats, while it was higher in a pure stand of peas. This was repeated in one out of three trials following the winter season. The nitrate to total mineral N ratio was higher in the pure stand of peas and lower in the intercrop and the pure oats. The studied crops did not give different residual effects in nitrogen and dry matter contents in a following oat crop. Conclusions are that intercropping may increase the efficiency of fixation and reduce risk of N leaching, but this is not necessarily reflected in current yields or subsequent crops.
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Claims 11
Claim · model-written summary
Nitrogen yield was sometimes affected by pea ratio in pea-oat intercrops.
Verbatim
t0“field pea intercropped with oats”
e1“Our results indicate that nitrogen yield sometimes, but not dry matter yield, was affected by pea ratio”
Claim · model-written summary
Dry matter yield was not affected by pea ratio in pea-oat intercrops.
Verbatim
t0“field pea intercropped with oats”
e1“Our results indicate that nitrogen yield sometimes, but not dry matter yield, was affected by pea ratio”
Claim · model-written summary
The efficiency of N fixation increased with decreasing pea ratio.
Verbatim
t0“field pea intercropped with oats”
e2“The efficiency of the fixation increased with decreasing pea ratio”
Claim · model-written summary
N-concentration of intercropped oats decreased with decreasing pea ratio.
- Taxon
- oats
Avena sativat0 - Treatment
- decreasing pea ratioe3
- Outcome
- N-concentratione3
- Direction
- decreasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“field pea intercropped with oats”
e3“This could be explained by competition for N from the intercropped oats, in which the N-concentration decreased with decreasing pea ratio”
Claim · model-written summary
Peas supplied the intercropped oats with nitrogen.
- Taxon
- oatsAvena sativat0
- Interactor
- peas
Lathyrus oleraceuse4other - Outcome
- nitrogene4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“field pea intercropped with oats”
e4“Results indicate that peas supplied the intercropped oats with nitrogen”
Claim · model-written summary
Residual soil mineral N after harvest was similar in the intercrop and in pure oats.
- Taxon
- oatsAvena sativat0
- Treatment
- intercrope5
- Outcome
- Residual soil mineral nitrogen after harveste5
- Direction
- similare5
- Comparator
- pure stand of oatse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“field pea intercropped with oats”
e5“Residual soil mineral nitrogen after harvest was similar in the intercrop to the pure stand of oats”
Claim · model-written summary
Residual soil mineral N after harvest was higher in pure pea stands, a pattern repeated in one of three trials after winter.
- Taxon
- field peat0
- Treatment
- pure stand of pease6
- Outcome
- Residual soil mineral nitrogen after harveste5
- Direction
- highere6
- Qualifier
- repeated in one out of three trials following the winter seasone7
Not reportedComparator
Verbatim
t0“field pea intercropped with oats”
e5“Residual soil mineral nitrogen after harvest was similar in the intercrop to the pure stand of oats”
e6“while it was higher in a pure stand of peas”
e7“This was repeated in one out of three trials following the winter season.”
Claim · model-written summary
The nitrate to total mineral N ratio was higher in pure pea stands.
- Taxon
- field peat0
- Treatment
- pure stand of pease1
- Outcome
- nitrate to total mineral N ratioe1
- Direction
- highere1
Not reportedComparator
Verbatim
t0“field pea intercropped with oats”
e1“The nitrate to total mineral N ratio was higher in the pure stand of peas and lower in the intercrop and the pure oats”
Claim · model-written summary
The nitrate to total mineral N ratio was lower in the intercrop and in pure oats.
- Taxon
- field peat0
- Treatment
- intercrop and the pure oatse1
- Outcome
- nitrate to total mineral N ratioe1
- Direction
- lowere1
Not reportedComparator
Verbatim
t0“field pea intercropped with oats”
e1“The nitrate to total mineral N ratio was higher in the pure stand of peas and lower in the intercrop and the pure oats”
Claim · model-written summary
The studied crops did not give different residual effects in nitrogen and dry matter contents in a following oat crop.
- Taxon
- oatAvena sativae1
- Treatment
- studied cropse1
- Outcome
- residual effects in nitrogen and dry matter contentse1
- Direction
- did not give differente1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“field pea intercropped with oats”
e1“The studied crops did not give different residual effects in nitrogen and dry matter contents in a following oat crop”
Claim · model-written summary
Intercropping may increase the efficiency of N fixation and reduce the risk of N leaching, but this is not necessarily reflected in current yields or subsequent crops.
Verbatim
t0“field pea intercropped with oats”
e1“Conclusions are that intercropping may increase the efficiency of fixation and reduce risk of N leaching, but this is not necessarily reflected in current yields or subsequent crops”
The same questions in other papers
intercropping · yield · Avena sativa (oats)Positive and negative results
9 papers in the same direction as this paper · 23 reporting no difference from an alternative
- positive
- no effect
- negative
29 papers more in this group
See all 33 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.