Claim · model-written summary
Clustering of maximum weed severity within fields was significant over the 10-yr period for all 43 weeds.
- Taxon
- Grass Seed Cropst0
- Interactor
- weedst0weed
- Outcome
- maximum severity within fieldse1
- Qualifier
- over the 10-yr period for all 43 weedse1
Not reportedMaterialGeneCompoundOrgan / stageSecond interactorSecond interactor roleTreatmentComparatorSettingDirectionValue
Verbatim
t0“Weeds of Grass Seed Crops”
e1“Clustering was significant for maximum severity within fields over the 10-yr period for all 43 weeds”
Title
GIS Analysis of Spatial Clustering and Temporal Change in Weeds of Grass Seed Crops
George W. Mueller-Warrant; Gerald W. Whittaker; William C. Young Weed Science 2008. doi:10.1614/ws-07-032.1
Other claims from this paper (16)
- Observation Maximum weed severity within fields clustered significantly in 78% of single-year analyses.
- Observation In the remaining 22% of single-year cases, weed distribution was random rather than dispersed.
- Observation German velvetgrass and field bindweed showed the strongest clustering with both Moran I and General G measures.
- Observation Distance for peak spatial autocorrelation ranged from 2 km for Agrostis spp. to 34 km for common velvetgrass.
- Observation Weeds with stronger spatial autocorrelation had a greater range between peak distance and maximum range of significance.
- Association Z-scores for General G high/low clustering were substantially lower than the corresponding Moran I values.
- Observation Average severity of wild carrot and field bindweed doubled from 1994 to 2003.
- Observation Wild carrot was the only weed clearly showing an increase in spatial autocorrelation.
- Observation Soil chemical and physical properties and soil-type and crop dummy variables explained small but significant portions of variance in weed occurrence and severity.
- Association Management practices that are relatively ineffective in controlling weeds played a greater role in causing weeds to cluster than highly effective practices.
- Observation Both types of practices impacted Italian ryegrass distribution.
- Observation Distance of peak high/low clustering among perennial weeds was smallest, at 1 to 3 km, for Canada thistle and field bindweed.
- Method / resource Adding a distance offset to inverse distance weighting removed the sensitivity of results and gave results closely matching the multiple fixed distance band method.
- Method / resource Kriging, Ripley K-function, Moran I and Getis-Ord General G gave roughly similar classifications of weeds with strongest and weakest spatial clustering.
- Method / resource Maximum severity analyses using inverse distance weighting were highly sensitive to a small number of overlapping fields.
- Observation The mapped output described dominant spatial features of weed distribution patterns.