Organic broccoli was grown in the fall of 2001 and 2002 at the Experimental Farm, Ibaraki University. The objective was to determine the yield responses, food qualities, and weeds suppression in a no-till production system in which mulch treatments included cover crops of forage soybean and Japanese millet as compared with the conventional cultivation production system. Two different killing cover crop methods that were the use of bush cutter and hammer knife mower, were applied to all mulch treatments.
Millet cover crop biomass showed the highest value that the ranged from 580kg/10a to 636kg/10a. Soybean N contents showed the highest value that the ranged 2.8kgN/10a to 6.3kgN/10a. Yields and head mass increased for millet mulch at an early harvest stage in both years. However, total yields were no significant differences between cover crop mulches and the conventional cultivation system. Broccoli sugar contents for millet mulch showed higher values compare with other treatment, and nitrate contents usually showed the lowest value. On the other hands, broccoli nitrate content for soybean mulch usually showed higher values comparewith other treatment. These results suggest that millet mulch would be an appropriate technique for organic broccoli production system because that would provide adequate soil nutrient condition.
