Annual grasses in crop rotations with grass seed production – a survey with special focus on Vulpia spp. in red fescue production
2013
Kryger Jensen, Peter | Kristensen, Kristian
This paper presents a survey of grass weeds in grass seed crops in Denmark. The survey is based on an analysis of data from a database containing monitoring of grass weeds in the period from 2004 to 2009 on an acreage of approximately 400,000 ha. The survey is based on weed monitoring carried out during a mandatory field inspection of grass seed crops. All fields grown with grasses for seed production are monitored shortly before harvest at a time when the weeds present are a result of a combination of the cropping history of the field, competition from the crop and the weed control carried out in the field. The survey showed that Poa annua , Elytrigia repens and Poa trivialis were the three most frequent grass weeds in grass seed crops. Furthermore, Bromus hordeaceus , Bromus sterilis , P. trivialis and Vulpia spp. showed an increasing frequency in the study period. The perennial weed, E. repens , and Dactylis glomerata were the only important grass weeds with a declining frequency during the six years. Vulpia spp. has recently become a significant problem in red fescue for seed production, and a significant increased frequency was seen during the study period. However, the study also showed that Vulpia spp. is primarily a problem in red fescue crops established in the autumn, whereas spring establishment of red fescue almost solves the problem with this primarily autumn-germinating grass weed.
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