WEED CONTROL AND FIELD MANAGEMENT WITH BARLEY LIVING MULCH IN ASPARAGUS PRODUCTION

It is not possible to intercultivate asparagus (Asparagus officinalis) fields with large agricultural machines because the crop grows in the field for a long time in the same field. Therefore, soil improvement and weed control are difficult. Experiments were conducted for weed control and field management with barley living mulch were observed in an asparagus field in Hokkaido, the cool and snow cover region in Japan. Barley cultivar 'Temairazu' with a strong winter habit for heading was used. When it is sown in spring, heading does not occur for lack of low temperature and only leaves emerge, so living mulch is formed. After sowing on April 15^th 2004, barley living mulch covered the ground-surface after mid-May, and reduced emerged weed quantity to 18% of the control, bare soil without barley, on July 15^th. Such living mulch continued to grow during the summer. In our observation, seeding density was more than 60-80 kg/ha for complete weed control. When sown after mid-May, the barley growth decreased the effect of weed control compared to the sowing date of April 15^th, 2 or 3 weeks before the beginning of the asparagus harvest. Weed control effect with living mulch of barley sown on May 15^th, 2004, showed a little reduction compared to the treatments of conventional methods, herbicide and tillage. Serious problems were not observed for spear harvest and it was possible to add organic matter into the soil in a barley living mulch system.