Effects of interplanting cold-reason grass on weeds biodiversity in ramie plantation in winter

Trifolium repens, Lolium perenne, and Astragalus sinicus were planted in fallow field after harvesting ramie(Boehmeria nivea) in winter to study the impacts of interplanting grass on the density, biological diversity and dominant species of weeds. One year after planting L.perenne, T.repens and A.sinicus, the overall densities of weeds were 59.2, 107.7 and 128.2 plant·m-2 and declined by 73.35%, 51.53% and 42.30% compared with control, respectively. The biomass of weeds were 62.33, 142.1 and 112.86 g·m-2 and declined by 78.11%, 50.31%, 60.53%, respectively. These results revealed that interplanting grass with these three cold-season grasses can reduce the hazard of weeds in ramie field and L.perenne were most effective. These three cold-season grasses did not remarkably change the categories of predominant weeds although Simpson evenness index and Shannon-Winner diversity index decreased a little bit. The biological diversity index of weeds after planting A.sinicus was slightly higher than that after planting T.repens and L.perenne.