Critical period of weed competition in direct seeded rice under saturated and flooded conditions

Field experiment was conducted at the Malaysian Agriculture Research and Development Institute (MARDI) station, Seberang Perai, Penang in off-season 2005 and main season 2005/2006, to determine the critical period of weed competition in saturated and flooded conditions. The experiment consisted of different seasons, namely weed free and no weeding periods. Sum Dominance Ratio showed that the weed compositions were different in the saturated condition, as compared to the flooded condition for both seasons. The dominance ranking of weed groups in the off- season in 2005 in saturated condition was sedges, followed by grasses and broadleaved, while during the main season of 2005/2006, grassy weeds were the most dominant, followed by sedges and broadleaved weeds. In the flooded condition, the dominance rankings of weed groups (such as broadleaved>grass>sedges) were the same in both seasons. The number of tillers, along with rice grains yield, was significantly affected by the weed competition in both saturated and flooded conditions. Yield loss due to weed competition was higher in the saturated condition (54.5%) than in the flooded condition (35.2%). Based on the 5% level of yield loss, the critical period in the off-season of 2005 was between 2-71 days, after sowing (DAS) in saturated condition, and 15-73 DAS in flooded condition. Meanwhile in the main season of 2005/2006, the critical period was between 0-72 DAS in the saturated condition and 2-98 DAS in the flooded condition.

[1]  J. Chandler,et al.  The Critical Period of Johnsongrass (Sorghum halepense) Control in Field Corn (Zea mays) , 1996, Weed Science.

[2]  A. S. Juraimi,et al.  Critical period for weedy rice control in direct-seeded rice , 2007 .

[3]  T. Michaels,et al.  The Critical Period of Weed Control in White Bean (Phaseolus vulgaris) , 1993, Weed Science.

[4]  B. L. Mercado.  Introduction to weed science. , 1979 .

[5]  W. Fox,et al.  Soil Water and Growth of Rice and Weeds , 1973, Weed Science.

[6]  Rebecca Kent,et al.  Influence of flood depth and duration on growth of lowland rice weeds, Cote d’Ivoire , 2001 .

[7]  F. Gravanis,et al.  Critical periods of weed competition in cotton in Greece , 2002, Phytoparasitica.

[8]  D. Johnson,et al.  Rice yield and productivity gaps in irrigated systems of the forest zone of Côte d'Ivoire , 1999 .

[9]  D. Datta,et al.  Principles and Practices of Rice Production , 1981 .

[10]  Rene C. Van Acker,et al.  Critical period of weed control in spring canola , 2001, Weed Science.

[11]  Clarence J. Swanton,et al.  The Critical Period of Weed Control in Grain Corn (Zea mays) , 1992, Weed Science.

[12]  K. Moody,et al.  Weed populations in transplanted and wet‐seeded rice as affected by weed control method , 1989 .

[13]  J. Norsworthy,et al.  Comparison of the critical period for weed control in wide- and narrow-row corn , 2004, Weed Science.

[14]  S. Bhuiyan,et al.  Water, tillage and weed interactions in lowland tropical rice: a review , 1996 .

[15]  Stephan M. Haefele,et al.  Timing of weed management and yield losses due to weeds in irrigated rice in the Sahel , 2004 .

[16]  S. Weaver.  Critical period of weed competition in three vegetable crops in relation to management practices , 1984 .

[17]  S. Datta,et al.  Handbook for weed control in rice. , 1991 .

[18]  S. Bhuiyan,et al.  Effect of water, tillage and herbicide on ecology of weed communities in intensive wet-seeded rice system , 1999 .