防除滩涂米草入侵的根际缓释方法

Controlled release method for herbicides in rhizosphere to prevent aggression of Spartina alterniflora in intertidal zone

为防除滨海滩涂互花米草入侵,探讨根际土壤缓释除草剂的新方法。该研究采用扩散法研究了蛭石、PE膜和合成壳聚糖膜3种缓释材料的根际缓释除草剂的性能,同时,采用根部浸泡试验验证根际施药防除互花米草的效果。结果表明,3种缓释材料的缓释性能差异显著,蛭石对草甘膦控释能力较弱,初始释放农药量最大,释放迅速,适合淤泥质潮滩;PE膜则表现出较强的控释能力,释放量较小,但整个过程释放量较稳定,适合沙质和近根际水体;壳聚糖膜介于两者之间。根部浸泡试验表明,0.25～1.00g/L草甘膦、0.09～0.23g/L百草枯、0.28～2.30g/L草铵膦根部浸泡2～6d即可显现毒杀互花米草效果,通过饱和土壤一维溶质渗滤模型计算,在点源释放模式下,除草际根部释放点间有效除草间距为50～60cm。研究证明了根际缓释除草剂防除互花米草具有可行性。

To guard effectively against the ecological aggression of the smooth cord-grass Spartina alterniflora growing in intertidal zone,a new method was considered to apply herbicides in rhizosphere soil with controlled release techniques.Three types of controlled release materials,vermiculite particles,polyethylene（PE） and chitin membrane,were tested on their herbicide-releasing characteristics,meanwhile,three herbicides,including glyphosate,parauat and basta,were evaluated on the effects of killing the smooth cord-grass.The results show that the controlled herbicide-releasing ability of vermiculite particles is weaker than the other two materials,and its initial releasing quantity is bigger,so it can be used for the muddy beach.On the contrary,that of PE was stronger,and therefore it is suitable for a sandy beach.Furthermore,that of chitin membrane is between the vermiculite particles and PE membrane.The three herbicides,glyphosate,paraquat and basta,can kill the grass effectively after 2-6 days of cultivation in 0.25-1.00 0.09-0.23 and 0.28-2.30 g/L solutions,respectively.One dimensional model for solute infiltration in saturated soil was used to modulate the herbicide migration,and the modulation result suggested that the distant between any two herbicide-releasing points should be set at less than 50-60 cm in field weeding practice.The experiment proved it is feasible in practice to guard against the ecological aggression of smooth cord-grass by controlled release of herbicides in rhizosphere.