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目的评价南水北调东线工程水源区“保芦”沙埋灭螺效果。方法于钉螺产卵期将成螺置于不同含沙量的环境饲养7 d,观察产卵情况。将钉螺置于采用江沙制成的饲养盘,在实验室观察其生存情况。水源区现场试验观察沙埋灭螺前后钉螺密度变化和芦苇生长情况。结果钉螺在纯江沙环境不产卵,江沙含量10%～100%各组产卵数与江沙含量呈显著负相关(r=-0.965,P=0.008)。钉螺在江沙环境的死亡率随时间增加而上升,25℃左右3、6个月钉螺死亡率分别达96.00%和100%。现场灭螺沙埋后、次年春季、汛期后、第3年春季均未发现钉螺;对照组采用药物灭螺后2周,活螺密度下降93.65%,经过汛期,活螺密度较灭螺前上升100%,至第3年春季活螺密度仍为0.37只/0.1 m2。沙埋后次年春季芦草生长良好。结论江沙环境不利于钉螺产卵和生存;现场应用沙埋法具有“保芦”灭螺效果,似还具有防止汛期钉螺扩散作用;沙埋法符合环境保护要求,可应用于南水北调东线水源区和沿江滩涂湿地钉螺控制。
Objective To evaluate the effects of waterlogging and snail embedding in the water source area of east route of South-to-North Water Diversion Project. Methods The snail spawning period will be screwed into different sediment concentrations in the environment feeding 7 days to observe the spawning situation. Place the snail on a feeding tray made of jiangsa and observe its survival in the laboratory. Field experiment in water source area to observe the changes of snail density and the growth of Phragmites communis before and after sand burying. Results Oncomelania did not spawn in the pure Jiangsha environment. The amount of spawning of 10% ~ 100% of the sand was negatively correlated with the content of Jiangsha (r = -0.965, P = 0.008). The mortality of Oncomelania snails in Jiangsha environment increased with time, and the death rates of snails at 96 hours and 25 months were 96.00% and 100%, respectively. After the snails were buried in the field, the snails were not found in the spring of the next year after the spring and flood season of the next year. The density of live snails decreased by 93.65% in the control group after two weeks of snail elimination. After the flood season, Rose by 100% to 0.37 mt / 0.1 m2 until the spring of April. Sand buried next spring reed grow well. Conclusion The sand environment is not conducive to oviposition and survival of Oncomelania snails. The application of sand-buried method has the effect of snail-killing, which may also have the effect of preventing the spread of snails in flood season. The sand-buried method accords with the requirements of environmental protection and can be applied to the east Line water source area and along the wetland snail control.