Abstract
This study was conducted to examine the effect of autumn puddling before wheat seeding and application of controlled-release fertilizer on the growth of rice direct-seeded in the wheat stand. Yield and quality of both rice and wheat were evaluated. Three kinds of controlled-release coated urea, LPS100, LPSS100 and LPS120, were applied at a 5 cm depth to a V-shape furrow at the time of rice direct seeding. Judging from the nitrogen release pattern and rice growth, LPSS100 was the most suitable for basal application, and LPS120 was suitable for top dressing at ear-formation stage of rice. None of the coated urea influenced yield and quality of wheat. Autumn puddling before wheat seeding was very suitable for rice direct seeding in mid-February. It hardened and leveled the paddy field, and therefore, sowing depth of rice seed was very uniform and the number of established rice seedlings per unit area was higher than in the field tilled before wheat seeding. Neither the seeding machine for wheat nor the combine for rice showed any harmful effects. By using autumn puddling and basal application of coated urea LPSS100, 4.94 tons ha-1 of wheat and 5.32 tons ha-1 of rice were harvested in the 0.94 ha paddy field and labor time was reduced to 23.5 hours ha-1, in 1999. These results showed that this cultivation system was labor-saving and produced a stable yield.
