Weed pressure is one of the most limiting factors in organic arable crops with increasing weed seed bank in cereal crops.
In addition to mechanical weed control carabids can re-duce weed seed bank in arable crops by predation (Westerman et al. 2003). Carabid population is known to be higher in organic fields than in conventionally farmed fields (Diekötter et al., 2010).
Preparing the seed cards
• Prepare 10 sand paper cards (5 cm x 5 cm) per field and 10 predator exclusion cages with 1 cm squared metal net to avoid predation by mammals and birds.
• Glue 10 poppy seeds on each card and place each card within an exclusion cage.
• Collect data twice during the crop cycle, preferably in spring for winter cereals (avoiding drought periods).
• Define two transects in the monitored field. Place 5 seed cards with exclusion cage along each transect and nail them into the floor (day D).
• Remove them after 4 days of exposure to predators
• Count the remaining seeds on each card.