Weed Spectrum And Their Management Strategies In Wheat Under Different Sowing Methods Planted At Varying Dates

Unwise use of herbicides has resulted in environmental and health problems not only for human beings and also for animals but it also caused some weed species to dominate fields due to resistance development against herbicides.Among the alternate ways of weed management in field crops application of allelopathy has shown tremendous scope in agricultural pest management.Different sowing methods and planting times has varying impact on the associated weeds. Studies on dynamics of weed flora and its management by allelopathy in wheat at varying sowing times planted by different methods were conducted at the Agronomic Research Area, Department of Agronomy, University of Agriculture, Faisalabad, Pakistan during 2008-09 and 2009-10.In the first experiment, weed flora under different sowing methods and planting dates was investigated. In second experiment allelopathic plant water extracts (PWE) of sorghum, sunflower and mulberry in combination with reduced doses of a herbicide in different sowing methods was evaluated. Whereas in third experiment, plant water extracts used in the second experiment in combination with reduced doses of a herbicide under different planting methods were assessed. Weed flora mainly consisted of Chenopodium album L. and Phalaris minor L., while few plants of Fumaria parviflora L., Avena fatua L., and Anagallis arvenses L. were also observed.It is noted that weeds if not controlled, can cause 60-66% yield losses in wheat. Maximum wheat productivity and net returns were obtained from wheat sown at November 15 on beds. Allelopathic PWE in combination with 1/3rd dose of herbicide provided as effective weed control as was achieved from label dose of herbicide during 2008-09 and 2009-10 which caused substantial yield increase (54%), suggesting that herbicide dose could be reduced by 67%.For achieving eco-friendly weed control and maximum productivity allelopathic PWE combined with 1/3rd dose of herbicide could be applied in wheat planted on beds at November 15