Monitoring the Spatial Variability of Knapweed (Centaurea diluta Aiton) in Wheat Crops Using Geostatistics and UAV Imagery: Probability Maps for Risk Assessment in Site-Specific Control

Assessing the spatial distribution of weeds within a field is key step to success site-specific weed management strategies. Centaurea diluta (knapweed) an emerging that causing major agronomic problem in southern and central Spain because its large size, difficulty controlling it, high competitive ability. The main objectives this study were examine variability C. density two wheat fields by multivariate geostatistical methods using unmanned aerial vehicle (UAV) imagery as secondary information delineate potential control zones for treatments based on occurrence probability maps infestation. primary variable was obtained grid samplings, variables derived from UAV acquired same day surveys. Kriging cokriging with UAV-derived displayed strong correlation used compare mapping performance. accuracy predictions assessed cross-validation. Cokriging generated more accurate lower RMSE kriging RVI, NDVI, ExR, ExR(2) (the best prediction knapweed density). Cokriged estimates generate risk assessment when implementing indicator kriging. This approach enabled delineation winter into different prescription according economic threshold.