ANNUAL WEED DISTRIBUTIONS CAN BE MAPPED WITH KRIGING

The authenticity of weed distribution maps prepared by the geostatisti cal estimation method, kriging, was investigated. We concentrated on t he total number of weed plants and the dominant weed genus Veronica sp p. in a 2.1-ha field of winter wheat. Different sampling distances wer e evaluated. Our analyses showed that kriging weed densities based on seedling counts collected in 0.25-m(2) circles in a sampling grid of a pproximately 10 mx10 m gave good agreement with actual observations. R educing the sampling grid to 20 mx30 m gave poor agreement. New sampli ng methods combined with positioning devices and injection sprayers ar e discussed with reference to site-specific weed management.