TOLERANCE OF CEREALS TO POST- EMERGENCE WEED HARROWING

Summary

This study defines crop tolerance to post-emergence weed harrowing as the combined effect of crop resistance and crop recovery. Crop resistance is the ability of the crop to resist soil covering and recovery is the ability to recover in terms of yield. In two experiments, resistance, recovery and tolerance were quantified in barley, oat, wheat and triticale by a new method based on digital image analysis. Important differences in resistance, recovery and tolerance among species were seen and resistance was not linked to recovery. Oat showed higher resistance than wheat, and barley. Triticale showed the lowest resistance. Oat and barley showed both lower ability to recover from soil covering than wheat, and triticale showed complete recovery. Triticale was the most tolerant species followed by wheat, oat and barley. Differences in tolerance caused species dependent crop yield losses in weed-free environments in the range of 0 to 10% for a practical relevant aggressiveness of weed harrowing.