Effects of planting ryegrass on farmland weeds and seedbank in winter

Abstract： The seed germination and growth of weed in farmland rely on the active seedbank obviously. To identify if planting ryegrass in fallow farmland in winter can reduce the active seedbank of the soil, present study investigated the number and species of weed and weed seedbank in the field of a rotation system with ryegrass and vegetables in Guangzhou City from 2009 to 2010. The results showed that planting ryegrass in the winter fallow land significantly reduced the weed seeds in the soil. The amount of weeds in the field originally planted with ryegrass was only 25.00% and 23.28% of that in the field originally planted with cabbage and the fallow land on average; and the active weed seedbank in the soil after planting ryegrass was only 67.85% of the original land. In addition, planting ryegrass in the winter fallow land could also affect the dominant species of weeds in the farmland; it could decline the larger weeds. Generally, planting ryegrass in the winter fallow land not only produced good quality forages, but also reduced the harm to crops by the weeds.