Effect of straw length and rotavator kinematic parameter on soil and straw movement by a rotary blade

Plenty of straw is left in field after harvesting, so soil-tillage tool interaction has changed into straw-soil-tillage tool interaction. To obtain the detailed movement of soil and straw and identify interaction between straw, soil and tillage tool, soil bin experiments were conducted by tillage with a rotary blade. Lengths of wheat straw were 130-230 mm with increments of 20 mm. One IT225 rotary blade was operated at rotary speed of 77r/min and forward speed of 0.222 m/s, and three rotavator kinematic parameters (6.8, 8.8 and 10.8) with working depth of 100 mm. Tin alloy cubes (2 cm3) and colored straw were used for measuring soil and straw movement. Moreover straw forward movement was observed greater than soil movement. The unburied percent of 150 mm straw decreased from 98% to 91% when rotavator kinematic parameters increased from 6.8 to 10.8. Further results indicated that straw mixtures might not fit for studying soil displacement, especially for lateral soil displacement; higher rotavator kinematic parameter resulted in soil and straw being spread in a larger area and more straw being buried. The average displacement of lateral and longitudinal straw tracers is recommended for forward straw displacement, and longitudinal straw tracer is used for side one.