Evaluation of Seedling Emergence in Rice Deep Seeded Using a Seeder for Upland Crops in Comparison with Wheat, Soybean and Corn

Abstract

To stabilize seedling emergence in direct seeding of rice in dry paddy fields, we conducted simultaneous deep seeding tests by seeding rice, wheat, soybean and corn using a seeder for upland crops. The target sowing depth was 3 cm in standard seeding and 7 cm in deep seeding. Compared with the other three crops, the number of days to emergence was longer and the emergence rate was lower at both sowing depth in rice, particularly extremely low at deep seeding. In deep seeded plants, although the first internode of wheat elongated to 3.9 cm, the hypocotyl of soybean elongated to 2.9 cm longer than in standard seeding, and the mesocotyl of corn elongated to 5.0 cm, the total length of the mesocotyl and second internode of rice was only 2.3 cm. Thus, deep seeding did not promote stem elongation in rice compared with the other three crops, which was related to the low emergence rate of deep seeded rice. Deep seeding should be avoided when conducting direct seeding of rice in dry paddy fields.