Impact du précédent cultural et de la fertilisation azotée sur la teneur en désoxynivalénol chez l’orge

Abstract

Many diseases affect cereals, but fusarium head blight associated with the presence of the fungus Fusarium graminearum is probably one of the most feared diseases in barley (Hordeum vulgare) production in Quebec. In addition to reducing grain yields, the fungus produces the toxin deoxynivalenol (DON), which can affect the health of livestock. An experimental study was conducted over 4 years (2002–2005) at the Research farm of Agriculture and Agri-Food Canada in Normandin to determine the impact of four previous crops (barley, dry pea, soybean, and red clover) and four nitrogen fertilization levels (0, 40, 80, and 120 kg·ha−1) on DON content of barley. The effect of the preceding crop on DON content of barley was significant for 3 years out of 4. Thus, in 2002, 2003, and 2005, the toxin contents were significantly higher when the previous crop was barley compared with dry pea, soybean, or red clover. In 2003, the DON contents were particularly high. For example, when barley was grown the previous year, the average toxin content was 22.5 mg·kg−1. The lowest DON contents were obtained when barley was seeded on a previous dry pea crop with an average content of 10.3 mg·kg−1. The DON contents of barley grown on a previous soybean or red clover crop were 15.2 and 13.4 mg·kg−1, respectively. In 2004, the effect of previous crops had no significant effect on DON content. Similarly, during the 4-year test, nitrogen fertilization had no significant effect on DON content of barley.