Claim · model-written summary
The relation of yield index to weed density was a curve in which the rate of yield decrease rose progressively with density.
Not reportedComparator
Verbatim
t0“Rice Plants”
e0“タイヌビエの発生本数による水稲収量”
e1“収量指数と発生本数との関係は, 発生本数の増加にともなつて, 収量減少速度の漸増する曲線として示される”
Title
Studies on the Damage to Rice Plants Due to Weed Competition
Kenji NODA; Keio OZAWA; Kazunori IBARAKI Journal of Weed Science and Technology 1968. doi:10.3719/weed.1968.49
Other claims from this paper (15)
- Intervention effect Barnyard grass density had almost no effect on rice plant height.
- Intervention effect In plots with many barnyard grass plants, rice elongation tended to be promoted in the middle growth stage.
- Intervention effect Barnyard grass markedly affected rice tiller number, with a conspicuous decrease from the middle growth stage.
- Intervention effect The tiller reduction affected final panicle number.
- Intervention effect The effect on rice yield became more marked as barnyard grass density increased.
- Intervention effect The yield loss was greater under heavy than light fertilisation.
- Intervention effect The yield loss was greater at sparse than medium and dense planting.
- Association Rice yield and total barnyard grass weight were related by logY = a - bX, with Y yield index and X weed weight.
- Observation The yield components contributing to yield loss from weed competition ranked panicle number, ripened grain weight, spikelets per panicle, ripening ratio.
- Intervention effect In mixed rice and barnyard grass stands the production structure declined quantitatively.
- Intervention effect In mixed stands rice LAI decreased.
- Intervention effect In mixed stands the quantitative development of assimilating and non-assimilating parts declined.
- Intervention effect In mixed stands the N content of the leaf blades decreased in the middle growth stage.
- Observation Rice reached its maximum nitrogen uptake early whereas barnyard grass kept absorbing until later.
- Observation The authors consider competition between the two plants for nitrogen uptake to be large up to the first half of growth.
Oryza sativa
Robinia pseudoacacia