Abstract
We carried out the tests to improve the performance of stubble disposing of rotary tiller. The tests have been done on the paddy fields at Miyazaki, Okayama and Miyakonojo after harvesting in connection with the increment of cut (number of tines, speed of rotary shaft, foward speed), tilling depth, number of tillings, soil moisture content.
The results was as follows;
(1) Between 32 tines and 16 tines in the same lead, remain ratio of all stubbles of former was smaller than that of latter at every districts.
(2) Remain ratio of all stubbles of tilling depty of 10cm was smaller than that of the depth of 5cm in the same increment of cut.
(3) Many small stubbles were scattered on the field when the moisture content of soil was little.
(4) Remain ratio of weed of 32 tines was a little smaller than that of 16 tines. Remain ratio of weed of the depth of 10cm was smaller than that of the depth 5cm in the same increment of cut.
(5) Germination percentage of rye of the largest increment of cut (16 tines, low shaft speed, 0.4m/s) was small and that of the smallest increment of cut (32 tines, high shaft speed, 0.2m/s) was also a little small.
(6) There were little stalkes on the field.
(7) When the depth of the first tilling was 5cm, the increment of cut was small and the depth of the second tilling was 10cm, both the remain ratio of all stubbles and the remain ratio of weed were small.
(8) Tilling accuracy of the smallest or medium increment of cut in single tilling was very excellent except in the case of high moisture content of soil.
