Abstract
Summary The effects of nitrogen fertilizer on the growth and density of natural weed populations in spring barley ( Hordeum vulgare L.) and winter wheat ( Triticum aestivum L.) were investigated in the absence of herbicide. An increased level of applied nitrogen did not enhance: weed germination, tended to decrease the total weed biomass and had a differential effect upon the biomass of individual weed species in both wheat and barky. In competition with barley, Chenopodium album L. and Lamium spp. had lower nitrogen optima than the crop, while Urtica urens L. had a higher nitrogen optimum. In competition with wheat, Stellaria media (L.) Vill., Lamium spp. and Veronica spp. had lower nitrogen optima than the crop. The systematic changes in nitrogen effect with time were analysed by fitting orthogonal polynomials to the growth and density curves. The methodology could be recommended for other studies in which time or other systematic factors are included, as it supplies information which a traditional analysis of variance cannot provide. Since seed production is positively correlated with biomass, so nitrogen level affects seed production and, hence, the seed pool and future weed population, suggesting that fertilizer usage can be exploited in an integrated programme of crop: weed management. A trend towards lower N fertilizer application owing to concerns about the environment willfavour most of the weed species investigated in these experiments and change the composition of weed populations.
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Claims 7
Claim · model-written summary
An increased level of applied nitrogen did not enhance weed germination in spring barley.
- Taxon
- spring barley
.jpg?width=60)
Hordeum vulgaree0 - Treatment
- An increased level of applied nitrogene1
- Interactor
- natural weed populationse0weed
- Outcome
- weed germinatione1
- Direction
- did not enhancee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“natural weed populations in spring barley ( Hordeum vulgare L.)”
e1“An increased level of applied nitrogen did not enhance: weed germination”
Claim · model-written summary
An increased level of applied nitrogen tended to decrease total weed biomass in spring barley.
- Taxon
- spring barleyHordeum vulgaree0
- Treatment
- An increased level of applied nitrogene1
- Interactor
- natural weed populationse0weed
- Outcome
- total weed biomasse2
- Direction
- decreasee2
- Qualifier
- tended toe2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“natural weed populations in spring barley ( Hordeum vulgare L.)”
e1“An increased level of applied nitrogen did not enhance: weed germination”
e2“tended to decrease the total weed biomass”
Claim · model-written summary
In competition with barley, Chenopodium album and Lamium spp. had lower nitrogen optima than the crop.
- Taxon
- barleyHordeum vulgaree0
- Interactor
- Chenopodium album
Chenopodium albume0weed - Outcome
- nitrogen optimae0
- Direction
- lowere0
- Comparator
- the crope0
LamiumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In competition with barley, Chenopodium album L. and Lamium spp. had lower nitrogen optima than the crop, while Urtica urens L. had a higher nitrogen optimum”
Claim · model-written summary
In competition with barley, Urtica urens had a higher nitrogen optimum.
- Taxon
- barleyHordeum vulgaree0
- Interactor
- Urtica urens
_Urtica_urens_-_leaves.jpg?width=60)
Urtica urense0weed - Outcome
- nitrogen optimume0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Urtica_urens_-_leaves.jpg?width=500)
Verbatim
e0“In competition with barley, Chenopodium album L. and Lamium spp. had lower nitrogen optima than the crop, while Urtica urens L. had a higher nitrogen optimum”
Claim · model-written summary
In competition with wheat, Stellaria media, Lamium spp. and Veronica spp. had lower nitrogen optima than the crop.
- Taxon
- wheat
Triticum aestivume0 - Interactor
- Stellaria media
Stellaria mediae0weed - Outcome
- nitrogen optimae0
- Direction
- lowere0
- Qualifier
- Veronica spp.e0
- Comparator
- the crope0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In competition with wheat, Stellaria media (L.) Vill., Lamium spp. and Veronica spp. had lower nitrogen optima than the crop”
Claim · model-written summary
Fertilizer usage can be exploited in an integrated programme of crop and weed management in spring barley.
- Taxon
- spring barleyHordeum vulgaree0
- Outcome
- fertilizer usage can be exploited in an integrated programme of crop: weed managemente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“natural weed populations in spring barley ( Hordeum vulgare L.)”
e1“suggesting that fertilizer usage can be exploited in an integrated programme of crop: weed management”
Claim · model-written summary
Lower N fertilizer application is expected to favour most weed species and change the composition of weed populations.
- Taxon
- spring barleyHordeum vulgaree0
- Treatment
- lower N fertilizer applicatione1
- Interactor
- weed speciese1weed
- Outcome
- composition of weed populationse1
- Direction
- changee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“natural weed populations in spring barley ( Hordeum vulgare L.)”
e1“A trend towards lower N fertilizer application owing to concerns about the environment willfavour most of the weed species investigated in these experiments and change the composition of weed populations”
The same questions in other papers
nitrogen · weed · Hordeum vulgare (barley)Positive and negative results
3 papers in the same direction as this paper · 5 in the opposite direction
- no effect
- negative
- no effect
5 papers more in this group
See all 9 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.