Abstract

Methods of controlling weeds without herbicides have become more important during the last few years. Especially vegetatively propagated weeds (perennials) as common couch (Agropyron repens) or creeping thistle (Cirsium arvense) are difficult to control without herbicides. This report discusses the possibilities of controlling vegetatively propagated weeds by using opaque sheet mulches. The sheet mulches should be used on soil stores before the soil is used in different types of plantations. The main question that the experiments should answer is the length of time the soil store must be covered by the sheet mulch. The weeds common couch and creeping thistle are used in the experiments. Common couch needs to be covered for between 7 and 18 weeks. The root fragments of creeping thistle seemed to decompose very easy. The root fragments died after between 3 and 10 weeks.