In Crop Mechanical Weed Control in Grain Crops.

In-crop weed control is a challenge in organic grain production as synthetic herbicides cannot be used. Managing crop competition and mechanically removing or suppressing weeds can potentially be used to control weeds. The objective of this research is to highlight the relative efficacy of different mechanical in-crop weed control methods that have been evaluated under organic conditions in the Canadian Prairies. Tine harrows can effectively control weeds at the seedling stage however the selectivity of harrows are often low often leading resulting in crop damage and reduced yields. Furthermore, the tine harrow does not have enough clearance to operate in systems with heavy surface crop residue. Rotary hoe can effectively control small, shallow germinating weeds even in crop residue. However, the timing of this operation is critical as weeds larger than the cotyledon stage are not controlled. Inter-row tillage can control larger weeds in the inter-row space with minimal damage to the crop. We have also evaluated these tools alone or in combination. Initial results suggest that rotary hoeing combined with inter-row cultivation can be very efficacious on weeds.