Spatial and Temporal Analysis of Weed Seedling Populations Using Geostatistics
- 1 September 1996
- journal article
- special topics
- Published by Cambridge University Press (CUP) in Weed Science
- Vol. 44 (3) , 704-710
- https://doi.org/10.1017/s0043174500094571
Abstract
An intensive field survey of an eastern Nebraska corn and soybean field was conducted to characterize the spatial structure and temporal stability of broadleaf weed seedling populations over two growing seasons. Anisotropy, the effect of direction on the relationship between observations, is present in the semivariogram for the velvetleaf and common sunflower populations in 1992 and 1993. The directional trends in aggregation are visible in kriged maps as elliptical shapes oriented east to west across the study area. In addition, there are two distinct zones of aggregation from north to south. These two distinct areas of aggregation are reflected as a ‘plateau’ in the north-south semivariogram. The distance over which this plateau extends indicates that the shape or size of the patch is contracting in the north-south direction (perpendicular to the crop row). The slope of the semivariogram in the east-west direction (aligned with the crop row) remains consistent from 1992 to 1993 suggesting that the shape of the patch is not changing. For sunflower populations, the slope of the north-south empirical semivariogram changes at 20 m, similar to the velvetleaf population semivariograms. This change, however, is reflected as a downward trend in the empirical semivariogram. The distance over which this trend occurs increases from 1992 to 1993 suggesting that seedling patch size was smaller in 1993 compared to 1992. Weed seedling establishment resulting from seed dispersal, differential seed and seedling mortality, or emergence may have resulted in the observed patch dynamics.Keywords
This publication has 17 references indexed in Scilit:
- A simulation of herbicide use based on weed spatial distributionWeed Research, 1995
- Value of information about weed distribution for improving postemergence control decisionsCrop Protection, 1992
- Geostatistical Tools for Modeling and Interpreting Ecological Spatial DependenceEcological Monographs, 1992
- Mathematical models in weed managementCrop Protection, 1991
- Using plant population biology in weed research: a strategy to improve weed managementWeed Research, 1991
- An Introduction to Applied Geostatistics.Journal of the American Statistical Association, 1991
- Spatial weed distribution and economic thresholds for weed controlCrop Protection, 1990
- The problem of weed patchinessWeed Research, 1990
- Field‐scale estimates of grass weed populations in arable landWeed Research, 1988
- On Hypothesis Testing in Ecology and EvolutionThe American Naturalist, 1983