Diversity Of Seed Bank Of Artificial And Natural Fresh Water Wetland Soils And The Variation With Fertilization And Cultivation

A long-term fertilized paddy field under rice/rape rotation from Taihu Lake region and some natural wetlands from Anhui province were chosen for studying soil seed bank.Weed seeds were collected by rinsing from the topsoil (0-15cm) and counted by microscopic examination. The effect of long-term fertilization on soil weed seed bank diversity, the relationship between weed seed diversity and crop yields was analyzed. More over, the diversity of soil seed bank between natural wetland and circumjacent paddy soil was compared. The main results are showed as follows:The fertilizer treatments were as follows: non-fertilizer (NF), chemical fertilizer only (CF), chemical fertilizer and pig manure combined (CMF), and chemical fertilizer plus rice crop stalk (CSF).In the cultivating seasons of both rice and rape, under the treatment of chemical fertilizer plus rice crop stalk, the density of soil weed seed bank was the lowest, whereas the total species number and diversity was the highest. Furthermore, the crop yields were maximal and the steadiest under this treatment. There was definite correlation among fertilizer treatments, soil weed seed bank diversity and crop yields. It was concluded that balanced fertilizer management helps to maintain soil weed seed bank diversity, increase crop yields, and prevent crop yields from fluctuating. Therefore, among the four fertilizer treatments, chemical fertilizer plus rice crop stalk was the best one to increase the productivity of agricultural ecosystems and simultaneously protect biodiversity.soil weed seed bank density of the two wetlands were more abundant than it which was in circumjacent paddy field, and the species quantity,richness index and Shannon-Wiener diversity index of the two wetlands were better than this of paddy fields. Moreover, the community structure of Shengjin Lake wetland was also better than Shibasuo wetland's. After wetland changed to paddy field, most of wetland plants disappeared, the plants which adapt to paddy field circumstance became dominant species, wetland plant community structure changed. Soil weed seed bank was one of the most important factor for plants restoration, but after wetland changed to paddy field, the density and diversity of soil weed seed bank decreased, it is bad for plants restoration. So we should artificially increase density and diversity of soil seed seed bank to protect and recover wetland.