Studies on herbicide application in wheat under paddy field conditions
1985
Koson Mengamphan (Chiang Mai Univ., Chiang Mai (Thailand). Faculty of Agriculture. Dept. of Agronomy)
This study aimed to established the control spectra and crop phytotoxic properties of different herbicides and to determine their influence on the yield and yield components of wheat. Two varieties of wheat (Triticum aestivum L.) Trigo 1 and Trigo 2 were applied with different herbicides namely diclofop, chlortoluron, metoxuron, bentazon, oxadiazon, and chlorsulfuron. Handweed and unweeded checks were provided in this experiment. Herbicide application done pre-emergence (3 days after planting), 7 day-post-emergance (DPE) and 14 DPE. Two weed species, Echinocloa colona L. and Trianthema portulacastrum L. were predominantly present in the area. Chlorsulfuron applied either pre or post emergence was found effective to both problem weeds and with complete control of T. portulacastrum L. Effective control of E. colona L. was observed when chlorsulfuron was applied 7 DPE. Diclofop effectively controlled E. colona L. when applied 7 DPE. but not to T. portulacastrun L. with a reduction in the weed population of 2.5 to 7 times below the unweeded check. Aside from chlorsulfuron, oxadiazon could completely eliminate T. portulacastrum L. when applied as post emergence herbicide at either 7 or 14 DPE while metoxuron could only duplicate this effect when applied at 14 DPE. The yield and yield components of the two varieties decreased with increasing population of weeds. The highest yield of 1983.9 kilograms per hectare was obtained from plots treated with chlorsulfuron (7 DPE at 40 g a.i/ha) which effectively controlled E. colona L. and T. portulacastrum L. Diclofop applied at 7 DPE at the rate of 1.5 kg a.i/ha has shown promise as a potential herbicide for wheat.
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