2001 Volume 46 Issue 4 Pages 282-290
The emergence of Monochoria vaginalis (Burm. f.) Kunth, Lindernia spp., Elatine triandra Schk. var. pedicellata Krylov, Rotala indica (Willd.) Koehne var. uliginosa (Miq.) Koehne, Ammannia multiflora Roxb., and Cyperus difformis L. was investigated in paddy soils kept under different moisture conditions before puddling and puddled in the middle of April, May, June and July in 1991 and 1992, respectively.
The number of emerged seedlings of weeds except for M. vaginalis and R. indica var. uliginosa increased in the soils under dry conditions from April to the puddling time, when the puddling time was delayed from April to July. The number of weeds remained almost constant in the soils under high moisture conditions from April to the puddling time, when the puddling time was delayed from April to July. The number was lower in soils under high moisture conditions during the ten-day period before puddling time than in the previous case. The number of M. vaginalis weeds was almost constant in paddy soils under different moisture conditions from April to the puddling time. The number of R. indica var. uliginosa decreased in paddy soils under different moisture conditions from April to the puddling time. Emergence pattern and emergence depth of the weeds were similar in paddy soils under different moisture conditions from April to the puddling time.
