The preliminary study of soil weed seed bank of Qiannan tobacco area.

To investigate the constitution and quantity of soil weed seed bank and the law of weed seeds germination process in tobacco area Changshun and Guiding,seed germination experiments were utilized through single factor random sample design.The results indicated that the weed seed bank in this area included 18 species,13 families of weeds and most of weeds were distributed in the depth between 0 cm and 10 cm in soil representing 54.41% of the weed growth amount in these two areas.The main kinds of weeds are Alopecurus aequalis Sohcl and Setaria gleuca(linn.) beauv which are nearly 70.48% of the total weeds amount and hence focus of weed control.At the two tobacco areas,weed seeds in Changshun is more than that in Guiding corresponding to 24180 grains per square meter in Changshun compared to 14660 grains per square meter in Guiding in soil depth of 030cm.