ANALYSIS OF THE SPATIAL-DISTRIBUTION OF W EEDS AND THE PLANNING OF A FUTURE MONITORING BY EXAMPLE OF THE OCCURRENCE OF CIRSIUM-ARVENSE L. WITHIN A FIELD SITE

The occurrence of Cirsium arvense L. within a sugarbeet field sire was completely recorded using intensity classes. By fourier analysis as a tool for characterizing large scale variability, we detected a period ic spatial structure. Small scale variability was characterized by var iograms providing information about the spatial autocorrelation struct ure. Using the information of the results of these procedures, monitor ing plans were suggested. Based on the data at reduced sampling points , we performed a reestimation of the original data set by Kriging and evaluated the correspondence. As data base for the various procedures, we used intensity classes as well as class centers. The results were compared.