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Considering the facts that the winter rapeseed is vulnerable to waterlogging, the furrow should be ditched while mechanical planting. The soil of middle and lower reaches of Yangtze River is sticky and its moisture content fluctuates greatly, which leads the stability of the furrow difficult to be guaranteed at the time of planting. In order to solve the above problems, the design of ditching furrows system for direct rapeseed seeder was carried out, and a combined ship type opener was proposed to achieve ditching the furrow. According to the principle of soil sliding and plow forming, the main structure and technical parameters of combined ship type opener were analyzed and determined. Based on the 2BFQ-8 direct rapeseed seeder whose work width was 2300mm, the ditching performance experiment on rear plow, ship type plow and combined ship type opener was carried out in rice stubble field, whose moisture content was 21.4%, 31.4% and 46.6%, soil compactness was 1320kPa, 846kPa and 539kPa. The furrow sections of furrows were mapped. The ditching performance experiment results indicated that shape of furrows ditched by ship type opener were more stable than that ditched by rear plow, and the width of seed bed which measured after ditched furrows by ship type opener was stable . The width and depth of furrows which ditched by combined ship type opener was 244.0~271.7mm and 194.0~229.5mm, its width stability coefficient and depth stability coefficient were more than 90%. The width of seed bed after ditching was 2039.0~2051.5mm. The experiment result revealed that the furrows ditched by combined ship type opener satisfied the actual production requirements of ditching furrows. The research conclusion had great theoretical value and practical significance to the design of opener which worked under the condition of soil with high moisture content.