Effects of Azolla on Nitrogen,Phosphorous and Growth of Spirogyra sp. in Flooded Paddy Field in Taihu Aera
绿萍对太湖地区稻田氮磷及水绵生长的影响

In this paper the effects of Azolla inoculation on the growth of Spirogyra sp. and the variation in concentrations of nitrogen and phosphorus in flood-water in paddy field were studied by a field experiment. Under the same level of fertilization, the concentrations of total nitrogen and ammonium nitrogen in flood-water with Azolla application were less than those without Azolla application. During the tillering stage, the assimilation and release of phosphorous in soil-water could be modulated with Azolla application, which reduced the risk of phosphorous loss. In addition, chlorophyll content in flood-water with Azolla application changed little, ranging from 20 mg/m3 to 45 mg/m3, in contrast, chlorophyll content without Azolla application increased gradually and was much higher than with Azolla application after 3 to 5 days, up to 85 mg/m3, indicating that the development of Azolla could inhibit algal bloom.