Abstract
In this study, the effect of plowed-in and incinerated wheat straw on the rice growth and weed incidence were examined in local field trials in Northern Kyushu to determine the most suitable method of processing the straw. The weed incidence was suppressed by plowed-in straw more effectively than by incinerated straw.Plowed-in straw suppressed tillering of rice but improved the ripening after heading of rice, tending to increase the yield. In pot experiments, either plowed-in wheat or barley straw greatly suppressed seed germination of paddy weeds. The weed-suppressing effect of plowed-in straw decreased with time but the effect was observed from the autumn of rice harvest to the heading stage of wheat in the next year. Plowing in all of the wheat straw,20-40 kg/a, had a weed suppressing effect, but plowing in 1/10 of the straw, tended to promote weed growth.Thus,plowing in all of the wheat straw in the paddy field suppressed weed incidence and the effect was retained for a long period.
