水稲代かき同時打込み点播機の開発と播種深度特性

抄録

We developed a seed-shooting seeder of rice combined with a tractor-mounted paddy harrow. Seeding is carried out simultaneously with the last puddling operation in a paddy field.
The seeder unit has a saw-toothed disc which revolves 100 to 1500rpm. The disc shoots seeds coated with calcium peroxide (CaO₂) onto the soil surface of a paddy field. The seeds are fed by the seed roller. Disc and the roller are driven by direct current motor (40W and 130W) with tractor battery. Using high speed camera, some basic room tests related to seeding depth was performed. The results were as follows:
1) The seeds velocity (CV=15%) right after shooting was about 0% to 10% higher than the peripheral velocity of the saw-toothed disc.
2) When the coated seed was shot into water, the seed velocity rapidly decreased and seed motion virtually came to a stop. The distance of the stopping point from the water surface was about 40mm (CV=27%).
3) When the seed was shot into agar (its viscosity was 50dPa·s), the sowing depth was in proportion to the seeds velocity, and CV of the sowing depth was 36% to 38%.