the effect of integrated weed management on yield and yield components of fennel

this experiment was carried out at the research farm of faculty of agriculture, university of zanjan in spring of 2012 to introduce an integrated weed management method in fennel. treatments were type of herbicide (trifluralin and pendimethalin), application dose (recommend dose in other crop (r), 75 percent r, 50 percent r, and 0 percent r) and supplemental control (none, one hand-weeding at 50 day after planting (dap) and, wheat straw mulch 2 kg m-2). a plot with whole season hand weeding was also included as check. the results showed that weed biomass loss, fennel yield and yield components significantly affected by weed control treatments. pendimethalin provided better weeds control than trifluralin. experimental results also showed that the use of herbicides resulted in reduced weed biomass but did not provide season long weed control without an additional supplemental control. overall, the recommended dose of pendimethalin (1320 g ai ha-1) followed by one hand-weeding at 50 dap produced consistently high yield (3561 kg ha-1) and weed biomass loss (92 percent).