代かき

The effect of frequent puddling on the growth of rice seedlings was examined, and the results are summarized as follows. The rooting of the seedling after planting was the same regardless of the number of tillings. The number of stems at the tillering stage when tilling was conducted 5 times was less than that when it was conducted once. At the maximum tillering stage, plant height and stem number were greater and the length of the leaves (4-5 leaves) and the internodal length of lower nodes tended to be more elongated when tilling was conducted 5 times than when it was conducted once. This was considered to be due to the fertilizer remaining which was caused by the lowered water penetration. Growth during the tillering and heading stages was faster when tilling was conducted only once than when conducted more frequently. The fresh leaf ratio after the heading stage was lower when tilling was conducted 5 times, which may be attributed to the mutual masking effect was conducted 5 times, which may be attributed to state of soil. The yield was lower and particularly, ripening during the latter part of the growth period was prominently lower when tilling was conducted 5 times than wehn conducted only once. This was considered to be due to the lowered activity of the roots which accompany the progress of soil reduction. Therefore, the above results suggest that the fewer the tillings before transplanting, the better the growth and yield of the rice.