种植方式对沉水植物生态修复效果的影响

Effects of Different Planting Patterns on the Ecological Restoration of the Submerged Plant Nets

针对可调式沉水网床种植沉水植物存活率低的问题,研究了捆绑式网床、粘扣式网床和网箱3种种植方式对3种沉水植物生态修复效果的影响。结果表明,用捆绑式网床种植的苦草(Vallisneria spiralis)、水盾草(Cabomba sp.)和轮叶黑藻(Hydrilla verticillata)在15 d后都出现负增长,每100 g沉水植物生物量的增长量(ΔW)分别为-0.011 7 g、-6.615 g和-13.095 g,且ΔW的负值随着时间的推移逐渐减小;粘扣式网床和网箱种植方式,除了第60天的轮叶黑藻组外,其余各组ΔW值都为正值,且第30天时的ΔW值高于第15天时,45 d后,粘扣式网床种植的苦草、水盾草和轮叶黑藻的ΔW值都明显下降,与第30天相比分别降低了95.1%、98.3%和99.9%。到第60天时,3种种植方式下的沉水植物对总磷、总氮和化学需氧量都有净化效果,三者之间差异显著(p<0.05),其中,网箱效果最佳,其次为粘扣式网床,捆绑式网床效果稍差。考虑到网箱成本较高,粘扣式网床更适用于生态修复工程中,而具体使用时,悬挂时间不宜过长,应在30 d前使网床的沉水植物着底。

For the problem of the low survival rate of submerged plants growing on the nets, we studied the effects of 3 planting methods, binding, thread gluing and caging, and on the ecological restoration for 3 submerged plants. The result showed that Vallisneria spiralis, Cabomba sp. and Hydrilla verticillata binded on nets presented negative growth after 15 days, and the growth quantity of each of the 100 g submerged plant biomass(ΔW) were-0.011 7 g,-6.615 g and-13.095 g. Additionally, the ΔW decreased over time. As for the thread gluing and caging planting methods, all of the ΔW values were positive, except that of Hydrilla verticillata group after 60 days. And the ΔW value at the 30 th day was higher than that at 15 th day. However, after 45 days, the ΔW values declined greatly, Vallisneria spiralis decreased 95.1%, Cabomba sp. 98.3% and Hydrilla verticillata 99.9%. After 60 days, total nitrogen, total phosphorus and chemical oxygen demand were all well absorbed by submerged plants through three planting methods(p<0.05), the preferential order was that caging, thread gluing, and binding. Because of higher cost of cages, the bed net with thread gluing is better for the ecological restoration engineering. And it's advisable to set the submerged plants thread gluing on bed nets to the bottom ahead of 30 th day, for guaranteeing submerged plants grow well and increasing the efficiency of cleaning water.