蕹菜和水鳖对泥质与沙质底养殖水体的净化效果研究

为解决淡水池塘集约化投饲养殖水体的营养物质富集问题,采用围隔试验方法,研究了蕹菜(Ipomoea aquatica)和水鳖(Hydrocharis dubia)两种植物对泥质和沙质两种底质养殖水体的净化效果。研究发现:泥质底水体的氨氮、亚硝酸盐氮和总磷(TP)自净去除率显著低于沙质底,而泥质底水体的高锰酸盐指数(CODMn)自净去除率显著高于沙质底(P<0.05);不同底质水体中,两种植物对水体氨氮、亚硝酸盐氮、总氮(TN)和CODMn的去除率显著高于相应对照组(P<0.05);12.5%与25.0%的水鳖处理对营养物质的去除率基本无显著差异(P>0.05),12.5%的蕹菜与水鳖处理组仅在泥质底水体中水鳖(MSBI)对氨氮的去除率显著小于蕹菜(MKC)以及MSBI对亚硝酸盐氮的去除率显著高于MKC(P<0.05);泥质底水体中植物处理对氨氮、亚硝酸盐氮、TN、TP和CODMn的最大去除率分别为60.07%、54.78%、52.68%、23.96%和47.32%,沙质底分别为72.43%、83.54%、57.20%、37.07%和40.75%;此外,试验末植物处理组水体的所测营养物质均存在一定程度的上升。沙质底水体中氨氮、亚硝酸盐氮和TP等营养物质波动较大且自净去除率高于泥质底;在泥质和沙质底水体中蕹菜和水鳖浮床均具有显著净化作用,本地种水鳖可作为生态浮床的潜力净水植物;浮床应用过程中应加强收割与收获等管理,以避免水体二次污染。

Study on purification effects of Ipomoea aquatica and Hydrocharis dubia on muddy and sandy aquaculture water

In order to solve the problem of nutrient enrichment in intensive aquaculture water of freshwater pond,the purification effects of Ipomoea aquatica and Hydrocharis dubia on muddy and sandy aquaculture water were studied using enclosure test method.The results showed that the removal rates of ammonia nitrogen,nitrite nitrogen and TP in muddy water were significantly lower than those in sandy water,and the removal rate of CODMn in muddy water was significantly higher than that in sandy water(P<0.05).In different water,both macrophytes could significantly remove more ammonia nitrogen,nitrite nitrogen,TN and CODMn than the corresponding control treatments(P<0.05).There was no significant difference in the nutrient removal rate between 12.5%and 25.0%of treatment with H.dubia(P>0.05),and 12.5%of treatment with I.aquatica and H.dubia was adopted only when the removal rate of ammonia nitrogen by MSBI in muddy water was significantly lower than that by MKC and the removal rate of nitrite nitrogen by MSBI was significantly higher than that by MKC(P<0.05).The maximum removal rates of ammonia nitrogen,nitrite nitrogen,TN,TP and CODMn by macrophytes in muddy water were 60.07%,54.78%,52.68%,23.96%and 47.32%respectively,while those in sandy water were 72.43%,83.54%,57.20%,37.07%and 40.75%respectively.Moreover,the contents of nutrients tested in the water treated with macrophytes increased to a certain extent at the end of the test.The contents of ammonia nitrogen,nitrite nitrogen,TP and other nutrients in sandy water fluctuated greatly and the removal rate was higher than that in muddy water.The floating beds of I.aquatica and H.dubia in muddy and sandy water had significant purification effects,and local H.dubia could be used as a potential water purification macrophyte in ecological floating bed.The management of harvesting should be strengthened in the application of floating bed to avoid the secondary pollution of water.