地膜覆盖对不同土层的湖北钉螺影响观察

Effects of film mulching on Oncomelania hupensis breeding in different soil layers

目的 观察农用地膜覆盖灭螺对土内钉螺和螺卵的影响.方法 选择潮湿的有螺田埂作为试验现场,分设施药覆膜组（采用50％氯硝柳胺乙醇胺盐可湿性粉剂,按2g/m2的剂量喷洒后覆盖地膜）、单纯覆膜组（不施药直接覆盖地膜）和对照组（不采取任何灭螺措施）.于施药覆膜后40 d和单纯覆膜后90 d分别对试验环境0、0～2、2～5、5～10和10～15 cm的土层进行钉螺调查.结果 覆膜40 d和90 d后,钉螺在土内分布的特点发生了改变,钉螺由土表向土内深层呈逐渐递增趋势（R2=0.9877,R2=0.7619）,土内钉螺死亡率高于对照组（x2=281.198,P＜0.001;x2=47.970,P＜0.001）,活螺平均密度较对照组均有下降（Z=-6.390,P＜0.001;Z=-4.681,P＜0.001）,幼螺的数量明显低于对照组（Z=-6.733,P＜0.001;Z=-5.131,P＜0.001）.结论 地膜覆盖对土内钉螺有很好的杀灭作用,并且可抑制钉螺第2代的繁殖和孳生.

Objective To study the effects of film mulching on Oncomelania hupensis and its eggs in soil. Methods The damp ridges with O. hupensis snails were selected and divided into niclosamide/film mulching group （sprayed with 50% wettable powder of niclosamide ethanolamine salt at 2 g/m2 and covered with mulch）, film mulching group （covered with mulch without niclosamide spraying）, and control group （not treated by molluscicidal measures）. Snail investigation was conducted in different soil layers （0, 0-2, 2-5, 5-10, and 10-15 cm） at 40 d after niclosamide spraying plus film mulching and at 90 d after film mulching alone. Results At 40 d and 90 d after film mulching, the snail distribution in soil changed, increasing by degrees from soil surface to the deep layer of soil （R^2=0.9877; R^2=0.7619）; compared with those of control group, the mortality of snails in soil was significantly higher （X^2=281.198, P〈0.001; X2=47.970, P〈0.001）, the average density of living snails was significantly decreased （Z=-6.390, P〈0.001; Z=-4.681, P〈0.001）, and the number of young snails was lower （Z=-6.733, P〈0.001; Z=- -5.131, P〈0.001）. Conclusion Film mulching is effective in killing snails in soil and can control the reproduction and breeding of the second generation of snails.