Design and experiment of cleaning and covering mechanism for no-till seeder in wheat stubble fields

A new type of cleaning and covering mechanism, used for no-till seeder in wheat stubble fields, has been designed to solve the problem of straw blocking of seeders and shortage of anti-blocking mechanisms in wheat residue covered fields in annual double cropping area of China. Spring tine was selected as the key part for cleaning, and transverse moving of straw and driving anti-blocking were chosen in this mechanism. Its parameters optimization was studied with the method of L9(34) orthogonal test in order to find out a reasonable form. The optimal combination of influencing factors was obtained by the experiment: linear velocity of spring tines was 20.72 m/s, operation speed was 4.5 km/h, arrangement of spring tines was seven rows and angle of baffle was 75°, meanwhile, the cleaning ratio was more than 98%, the covering evenness and width were 7.48 and 2.89 m respectively. The field experiment of seeding performance of no-till seeder on which the mechanism fixed was conducted according to "Testing Methods of Single Seed Drills", and the result showed that the qualified rate of spacing, the miss rate, the multiples rate and the coefficient of variation of qualified spacing satisfied the requirement of superior class, the sowing depth rate attained the requirement of first class, under the condition that the theory spacing were 6 and 8 cm, and the theory sowing depth was 3～5 cm. Above all, the cleaning and covering mechanism has important value in solving the problem of no-till mechanization seeding in wheat stubble field.