Weed seedbank dynamics in maize under different herbicide regimes

Abstract

The influence of different herbicide regimes on the size and composition of the soil weed seedbank in maize was studied over three years Preemergence atrazine alachlor atrazine alachlor or no herbicide treatments were imposed on the same plots each year Soil samples to 100 mm depth were collected each autumn and spring and the seedbank was estimated by seed extraction and seedling emergence Data showed strong positive correlation between the two methods Soil seedbank increased dramatically by each autumn but declined by spring The total seedbank increased over three years in the no herbicide treatment Good weed control by atrazine alachlor kept seedbank density at low levels However seed numbers increased particularly in the first two years with only partial weed control using atrazine or alachlor singly A sharp increase of fathen (Chenopodium album) seeds illustrated the danger of building seedbanks of weeds which become tolerant to the strategies used