Reducing Herbicide Injury to Direct-Seeded Rice by Coating Seeds with Activated Carbon

Abstract

Pregerminated seeds of rice (Oryza sativa L. var. ”Tainan 5”) coated with activated carbon sustained less injury to herbicides than those without coating during two crop seasons of direct seeding in paddy field. Seeds coated with activated carbon greatly reduced the injury of rice seedlings to butachlor (N-(butoxymethyl)-2-chloro-2', 6'-diethyl-acetanilide) applied at 1.5 kgai and 2 kg ai/ha and benthiocarb+CNP (s-4-chloro-benzyl) N, N-diethylthiolcarbamate) + 2, 4, 6-trichlorophenyI-4-nitrophenyl ether) applied at 3, 9 kgai/ha and 5.2 kgai/ha 2 days before seed sowing (DBS), and 0, +3, and +5 days after seed sowing (DAS) in the test fields. Flooding started on 4, 7, 10 DAS in the second rice crop, and on 6, 9, 12 DAS in the first rice crop did not affect the protection of seedlings from the herbicide injury coated with activated carbon. In order to reduce herbicide injury and to get the best control of weed on direct seeded rice, benthiocarb+CNP applied at 3.9 kgai/ha at 2 DBS or at 2.6 + 2.6 kgai/ha at 2 DBS and at 5 DAS, respectively, is advisable, while water flooding started at 7 to 10 DAS in the second rice crop and 9 to 12 DAS in the first crop.