Studies on the weeder for walking Tractor (4)

Adaptability for Direct Seeding on Drained Paddy (2) Influence on loss of Rice and weed

Abstract

The authors applied the weeder to directly seeded paddy field and obtained the following results.
(1) When the weeder was used at germination time of paddy, the germination percentage was rather heightened.
(2) When the depth of tines of weeder was 2.5cm and the interval of locus of them was 1.25cm which were standard working conditions, losing ratio of rice plant was 5-10% and that of rice stubbles was nearly 0%. But if the soil moisture was above 40%, d. b. loss of stubbles was found a little because the stubble were buried under soil.
(3) When the weeder was used to the weeding after rotary tiller broadcasting and to working the weeding after submerging, loss of rice plant was almost none.
(4) Lossing ratio of weed was about 90% in standard working conditions, but that differed more or less with depth of tines, soil moistures and times of working.
(5) When various weeding methods were compareds during thirty days after seeding, the weeding effect of using the weeder together with DCPA was best and that of the weeder only was the second and that of DCPA only was the third.
(6) In a rainy season, perfect weeding of wild sawa millet was carried out when the weeder was used once after two applieations of DCPA or when the weeder was used twice after one application of DCPA
(7) Using the weeder with standard working conditions, the adaptability of the weeder for directly seeded paddy field was recognized good enough even if the use was made during the rainy season.