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目的 研究护堤隔离沟改造钉螺孳生环境 ,消灭钉螺的效果。方法 以有隔离沟洲滩为试验组 ,无隔离沟洲滩为对照组。在两组外洲钉螺分布高程设置网箱 ,人工投活螺 ,比较钉螺产卵数量、幼螺生长发育状况、钉螺自然死亡率和感染螺密度 ,测量隔离沟区域洲土含水量 ,调查隔离沟沉积层各年间钙化螺密度。结果 试验组外洲无钉螺孳生。当东洞庭湖水位退至 2 5 m左右 ,对照组钉螺分布带洲土平均含水量 38.1% ,高于试验组 2 8.3% ;人工投活螺后对照组产卵数高于试验组 ;试验组幼螺出现率显著低于对照组和室内模拟现场。春季网箱外湖水中捞幼螺数 ,试验组显著低于对照组 ;网箱内秋季查螺 ,试验组钉螺自然死亡率 (77.92 % )显著高于对照组 (4 1.6 7% ) ;隔离沟淤积层内钙化螺筛洗 ,上层显著低于中层 ,中层又低于底层。莫河铺外洲对照组网箱内活螺密度、感染螺密度显著高于试验组。对照组外洲高杆植被生长茂盛 ,试验组外洲无高杆植被。结论 洞庭湖退水期间 ,植被被淹死 ,气温较高 ,隔离沟能迅速沥干洲土积水 ,改变了洲滩潮湿的环境 ,不适宜钉螺孳生
Aim To study the improvement of snail breeding environment and the elimination of snail by the berm trench. Methods To isolate Daozhou Beach as test group and without isolation Douchu Beach as control group. Cages and artificial live snails were set up in two groups, the number of spawning eggs, the growth and development of snails, the natural mortality of snails and the density of infected snails were measured. The soil water content in the isolation gully area was measured, Deposition calcareous density in each year. Results Test group outside the non-snail breeding. When the Dongting Lake water level retreated to about 25 m, the snail distribution in the control group was 38.1% higher than that in the experimental group, which was 8.3% higher than that in the experimental group. The number of eggs laid in the control group after artificial live snails was higher than that in the experimental group. The incidence of snail was significantly lower than the control group and indoor simulation field. In spring, the number of young snails in the lake was significantly lower than that in the control group. The natural mortality of snails in the experimental group was significantly higher than that of the control group (77.62% Sludge calcification spiral sieve washing, the upper significantly lower than the middle, lower than the middle and bottom. The molluscic density and the density of infected snails in the control group were significantly higher than those in the experimental group. In the control group, the high pole vegetation outside the continent flourished, and the test group had no pole vegetation outside the continent. Conclusion During the retreating period of Dongting Lake, the vegetation is drowned and the temperature is high. The isolation ditch can quickly drain the water of the terra cotta, change the wet environment of Chaoban, and is not suitable for snail breeding