Abstract
Paddy (Oryza sativa L. var. Taiching-127) fields of Kirtipur, central Nepal, were studied to evaluate the effects of weeds on crop yield during June to October 2003. Weed community was recorded in permanently marked plots (2 x 2 m2 each), and grain and straw yields were measured. The effect of aqueous extracts (2 to 10%) of leaf, stem and root of dominant weeds (Echinochloa colona, E. crusgalli, Cyperus iria and Ageratum conyzoides) on germination and seedling growth of the paddy (Taiching-127) was examined in the laboratory. Altogether 52 weed species (27 dicot and 25 monocot) belonging to 32 genera and 15 families infested the paddy. The maximum weed density was observed in September (105 pl/m2). There was significant reduction in straw and grain yield of paddy in weedy plots and negative correlation between weed species richness and straw yield. Crop weed competition reduced straw yield by 13% to 38% and grain yield by 25% to 47%. Weed growth changed pH and reduced soil nitrogen and phosphorus content. Aqueous extracts of root, stem and leaf of dominant weeds (Echinochloa colona, E. crus-galli, Cyperus iria and Ageratum conyzoides) showed a weak effect on seeds germination however most of them had inhibitory effect on root and shoot elongation of paddy seedlings. Root elongation was more sensitive to allelopathic inhibition than shoot elongation. Stem extract of these weeds showed higher inhibition on seedling growth of paddy than leaf and root extract except in Ageratum conyzoides in which root extract showed highest inhibition. Keywords: Allelopathy; Crop-weed competition; Soil nutrients; Germination; Grain yield. DOI: 10.3126/sw.v5i5.2665 Scientific World, Vol. 5, No. 5, July 2007 100-106
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 14
Claim · model-written summary
The paddy plots contained 52 weed species.
Verbatim
e0“Altogether 52 weed species (27 dicot and 25 monocot) belonging to 32 genera and 15 families infested the paddy.”
Claim · model-written summary
Weed density peaked in September at 105 pl/m2.
Not reportedTaxonInteractor
Verbatim
e0“The maximum weed density was observed in September (105 pl/m2).”
Claim · model-written summary
Weedy plots had significantly reduced straw yield.
Verbatim
e0“There was significant reduction in straw and grain yield of paddy in weedy plots”
Claim · model-written summary
Weedy plots had significantly reduced grain yield.
Verbatim
e0“There was significant reduction in straw and grain yield of paddy in weedy plots”
Claim · model-written summary
Weed species richness was negatively correlated with straw yield.
Not reportedTaxon
Verbatim
e0“negative correlation between weed species richness and straw yield”
Claim · model-written summary
Crop weed competition reduced straw yield by 13% to 38%.
Not reportedTaxon
Verbatim
e0“Crop weed competition reduced straw yield by 13% to 38%”
Claim · model-written summary
Crop weed competition reduced grain yield by 25% to 47%.
Not reportedTaxonInteractor
Verbatim
e0“grain yield by 25% to 47%”
Claim · model-written summary
Weed growth changed soil pH.
Not reportedTaxonDirection
Verbatim
e0“Weed growth changed pH and reduced soil nitrogen and phosphorus content.”
Claim · model-written summary
Weed growth reduced soil nitrogen and phosphorus content.
Not reportedTaxon
Verbatim
e0“Weed growth changed pH and reduced soil nitrogen and phosphorus content.”
Claim · model-written summary
Dominant weed extracts had a weak effect on paddy seed germination.
Not reportedTaxonComparatorDirection
Verbatim
e0“Aqueous extracts of root, stem and leaf of dominant weeds (Echinochloa colona, E. crus-galli, Cyperus iria and Ageratum conyzoides) showed a weak effect on seeds germination”
Claim · model-written summary
Most weed extracts inhibited paddy root and shoot elongation.
Not reportedTreatmentComparator
Verbatim
e0“most of them had inhibitory effect on root and shoot elongation of paddy seedlings”
Claim · model-written summary
Root elongation was more sensitive to allelopathic inhibition than shoot elongation.
Not reportedTaxon
Verbatim
e0“Root elongation was more sensitive to allelopathic inhibition than shoot elongation.”
Claim · model-written summary
Stem extracts caused higher inhibition of paddy seedling growth than leaf and root extracts.
Verbatim
e0“Stem extract of these weeds showed higher inhibition on seedling growth of paddy than leaf and root extract”
Claim · model-written summary
For Ageratum conyzoides, root extract had the highest inhibition.
- Treatment
- root extracte0
- Interactor
- Ageratum conyzoides
Ageratum conyzoidese0weed - Outcome
- inhibitione0
- Direction
- higheste0
Not reportedTaxonComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“except in Ageratum conyzoides in which root extract showed highest inhibition”
The same questions in other papers
botanical · growth · Oryza sativa (rice)Positive and negative results
77 papers in the same direction as this paper · 133 in the opposite direction
- positive
- positive
- positive
207 papers more in this group
See all 211 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.