The Effect of Lodging and Time of Harvest on Deoxynivalenol Contamination in Barley and Oats

A split‐split plot design was used to study the effect of lodging and time of harvest on the formation of the Fusarium toxin deoxynivalenol (DON). Altogether 19 experimental fields were included in the study, which was carried out over the period 1991–1993. There were two cultivars each of barley and oats tested. Half of each field was lodged artificially using a drum roller to flatten the crop about 3 weeks after ear emergence. The grain was harvested at the stage of mealy ripe and about 15 and 30 days after. The DON concentratioti in the grain was in descending order influenced by lodging, cultivar, experimental field, year and time of harvest. When paired plots were compared a distinct increase (more than 65%) in the DON concentration was found in samples from 49% of the plots with lodging compared with their pair plot. Both a decrease and an increase in the DON content were detected in the period from the first time of harvest to the second and third titne of harvest. The overall contamination level of DON was found to be higher in the samples of barley compared to oats.