Abstract
Summary: Résumé: Zusammenfassung Responses of upland rice ( Oryza saliva L.) and the weeds Amaranthus spinosus L., Cyperus rotundus L., Eleusine indica (L.) Gaertn., and Rottboellia cochinchinensis (Lour.) W. D. Clayton to nitrogen (N) and time of N application were studied in the glasshouse both in monoculture and in mixture. The N response of two rice cultivais and R. cochinchinensis in monoculture levelled off between 69 and 103 mg N kg −1 air‐dried soil, whereas the other weed species continued to respond beyond 103 mg N kg −1 air‐dried soil. At high N application rates. N uptake by weeds was higher than that by rice; weeds used N more efficiently. Weeds, which had high dry matter production at high N application rates in monoculture, were most competitive at low N and least sensitive to low applied N. Nitrogen application levels sub‐optimal to rice reduced the competitive ability of rice when in mixture with E. indica, R. cochinchinensis , and A spinosus , but not with C. rotundus . Although N response of a plant species generally declined with age, interspecific differences were observed. Timing of N application can be exploited in rice‐weed management. Les effets d'applications d'azote sur la croissance, l'efficacité de l'utilisation de l'azote et l'interaction riz‐mauvaises herbes Les réponses du riz pluvial ( Oryza sativa L.) et des mauvaises herbes Amaranthus spinosus L., Cyperus rotundus L., Eleusine indica (L.) Gaertn., et Rottboellia cochinchinensis (Lour.) W. D. Clayton à des applications d'azote, et à la période de ces applications, ont étéétudiées en serre, en cultures pures et en associations. Les réponses à l'azote de deux variétés de riz et de R. cochinchinensis en culture pure montrent un plateau entre 69 et 103 mg N kg −1 de sol séchéà l'air, alors que les autres mauvaises herbes continuaient de répondre au delà da cette dernière dose. Aux doses élevées d'azote, les mauvaises herbes prélevaient davantage d'azote que le riz et elles l'utilisaient plus efficacement. Les mauvaises herbes qui, en culture pure, montraient une forte production de matière sèche aux doses d'azote élevées, étaient les plus compétitives à faibles doses d'azote et les moins affectées par les faibles doses. Les doses d'azote sub‐optimales pour le riz réduisaient son aptitude à la concurrence quand il était associéà A. spinosus, E. indica et R. cochinchinensis , mais non à C. rotundus . Bien que chez toutes les espèces la réponse à l'azote déclinait généralement avec l'âge des plantes, des différences interspécifiques ont été observées. La période d'application de l'azote pourrait être exploitée dans la maîtrise des mauvaises herbes du riz. Wirkung der Stickstoffdüngung auf das Wachstum, die Stickstoff‐Assimilation und die Konkurrenz zwischen Unkraut und Reis Die Wirkung von Stickstoff (N) und des Zeitpunkts der Stickstoffdüngung auf Hochlandreis ( Oryzasativa L.) und die Unkrautarten Amaran thus spinosus L., Cyperus rotundus L., Eleusine indica (L.) Gaertn. und Rottboellia cochinchinensis (Lour.) W. D. Clayton in Rein‐ sowie Mischbeständen wurde im Gewächschaus untersuchte. Die Reaktion auf die Stickstoffgaben begann bei 2 Reissorten und Rottboellia co‐chinchinensis bei 69 und 103 mg N kg −1 lufttrockenen Boden, während die anderen Unkrautarten bei mehr als 103 mg N kg −1 lufttrockenen Boden reagierten. Bie hohen N‐Gaben war die N‐Auf‐nahme der Unkräuter stärker als beim Reis, und die Unkräuter setzten den Stickstoff besser um. Unkräuter mit hoher Trockenmasseproduktion in Reinkulture bei hohen N‐Gaben waren bei niedrigen N‐Gaben am konkurrenzstärksten. Suboptimale N‐Gaben verminderten die Konkurrenzkraft des Reises in Mischbeständen mit Eleusine indica, Rottboellia cochinchinensis, Amaranthus spinosus , aber nicht mit Cyperus rotundus . Obwohl die N‐Wirkung bei den Pflanzenarten allgemein mit dem Alter abnahm, lieβen sich zwischen den Arten Unterschiede beobachten. Der Zeitpunkt der N‐Düngung kann für die Steuerung der Konkurrenz der Unkräuter mit Reis genutzt werden.
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Claims 12
Claim · model-written summary
Rice and R. cochinchinensis nitrogen responses levelled off at 69–103 mg N per kg soil.
- Taxon
- rice
Oryza sativae0 - Interactor
- R. cochinchinensis
Rottboellia cochinchinensise0weed - Outcome
- N responsee0
- Direction
- levelled offe0
- Value
- 69 and 103 mg N kg −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The N response of two rice cultivais and R. cochinchinensis in monoculture levelled off between 69 and 103 mg N kg −1 air‐dried soil”
Claim · model-written summary
Other weed species continued responding above 103 mg N per kg soil.
- Taxon
- riceOryza sativat0
- Interactor
- other weed speciese0weed
- Outcome
- other weed species continued to responde0
- Direction
- continued to responde0
- Value
- 103 mg N kg −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“whereas the other weed species continued to respond beyond 103 mg N kg −1 air‐dried soil”
t0“rice‐weed interaction”
Claim · model-written summary
At high N rates weeds took up more N than rice.
- Taxon
- riceOryza sativae0
- Interactor
- weedse0weed
- Outcome
- N uptake by weedse0
- Direction
- highere0
- Comparator
- ricee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At high N application rates. N uptake by weeds was higher than that by rice”
Claim · model-written summary
Weeds used N more efficiently than rice.
- Taxon
- riceOryza sativae1
- Interactor
- weedse0weed
- Outcome
- weeds used Ne0
- Direction
- more efficientlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“weeds used N more efficiently”
e1“N uptake by weeds was higher than that by rice”
Claim · model-written summary
Weeds with high dry matter at high N were most competitive at low N.
- Taxon
- riceOryza sativat0
- Treatment
- low Ne0
- Interactor
- Weedse0weed
- Outcome
- most competitivee0
- Direction
- most competitivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Weeds, which had high dry matter production at high N application rates in monoculture, were most competitive at low N”
t0“rice‐weed interaction”
Claim · model-written summary
Weeds with high dry matter at high N were least sensitive to low N.
- Taxon
- riceOryza sativat0
- Treatment
- low applied Ne0
- Interactor
- Weedse0weed
- Outcome
- least sensitivee0
- Direction
- least sensitivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Weeds, which had high dry matter production at high N application rates in monoculture, were most competitive at low N and least sensitive to low applied N”
t0“rice‐weed interaction”
Claim · model-written summary
Suboptimal N reduced rice competitive ability with E. indica.
- Taxon
- riceOryza sativae0
- Treatment
- Nitrogen application levels sub‐optimal to ricee0
- Interactor
- E. indica
Eleusine indicae0weed - Outcome
- competitive ability of ricee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen application levels sub‐optimal to rice reduced the competitive ability of rice when in mixture with E. indica, R. cochinchinensis , and A spinosus , but not with C. rotundus”
Claim · model-written summary
Suboptimal N reduced rice competitive ability with R. cochinchinensis.
- Taxon
- riceOryza sativae0
- Treatment
- Nitrogen application levels sub‐optimal to ricee0
- Interactor
- R. cochinchinensisRottboellia cochinchinensise0weed
- Outcome
- competitive ability of ricee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen application levels sub‐optimal to rice reduced the competitive ability of rice when in mixture with E. indica, R. cochinchinensis , and A spinosus , but not with C. rotundus”
Claim · model-written summary
Suboptimal N reduced rice competitive ability with A spinosus.
- Taxon
- riceOryza sativae0
- Treatment
- Nitrogen application levels sub‐optimal to ricee0
- Interactor
- A spinosus
Amaranthus spinosuse0weed - Outcome
- competitive ability of ricee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen application levels sub‐optimal to rice reduced the competitive ability of rice when in mixture with E. indica, R. cochinchinensis , and A spinosus , but not with C. rotundus”
Claim · model-written summary
Suboptimal N did not reduce rice competitive ability with C. rotundus.
- Taxon
- riceOryza sativae0
- Treatment
- Nitrogen application levels sub‐optimal to ricee0
- Interactor
- C. rotundus
Cyperus rotunduse0weed - Outcome
- competitive ability of ricee0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen application levels sub‐optimal to rice reduced the competitive ability of rice when in mixture with E. indica, R. cochinchinensis , and A spinosus , but not with C. rotundus”
Claim · model-written summary
Nitrogen response generally declined with plant age, with species differences.
- Taxon
- riceOryza sativat0
- Organ / stage
- agee0
- Outcome
- N responsee0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although N response of a plant species generally declined with age, interspecific differences were observed”
t0“rice‐weed interaction”
Claim · model-written summary
The authors propose timing N applications for rice weed management.
- Taxon
- riceOryza sativae0
- Outcome
- Timing of N application can be exploited in rice‐weed managemente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Timing of N application can be exploited in rice‐weed management”
The same questions in other papers
nitrogen · Eleusine indica · Oryza sativa (rice)Positive and negative results
1 in the opposite direction
- positive
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.