PURPOSE: To perform sowing of rice seed by laying a continuous sheet along a groove while digging the groove on a paddy field and sowing rice seed on the sheet, thereby preventing the collapse of a groove.

CONSTITUTION: A long sheet (a) made of paper, etc., is laid in folded state on a groove while digging the groove on a paddy soil and is fixed e.g. by placing soil on side edges of the sheet or burying the side edges into the soil. Rice seeds (s) are sowed on the sheet (a) and the depth of water between the soil surface E and the water surface W is adjusted to about 5mm. The depth of the groove is about 10mm. When the sheet (a) is decomposed by degradation, etc., the side wall of the groove is collapsed and the rice seeds are covered with soil.