稻虾鳝立体种养模式对水体环境的影响

Effects of Integrated Aquaculture Model of Rice-Shrimp-Eel on Water Environment

为探明稻虾鳝立体综合种养模式对水体环境的影响,在2020年8—10月于河南信阳选取1块2.0×10~4 m~2稻渔综合种养试验基地,在环沟不同位置设置网箱养殖黄鳝,每15 d对网箱内、外及不同边侧环沟所设4个采样点内的水样进行采集和水温、溶解氧、pH、总磷、总氮、硝态氮、亚硝态氮和氨氮等指标检测。试验结果显示,不同时期网箱内的水体溶解氧水平始终最低,且网箱内、外水体溶解氧均低于远离网箱的对侧环沟(P>0.05),4个采样点pH差异不显著,网箱内、外水体氨氮显著高于对侧环沟(P<0.05),亚硝态氮、硝态氮含量显著低于对侧环沟(P<0.05)。网箱内、外水体总氮、总磷高于其他位点,总氮呈上升趋势、总磷呈下降趋势,对侧环沟内水体总氮、总磷呈上升趋势。试验结果表明,稻虾鳝立体综合种养模式虽然会增加网箱内外残饵和粪便的积累导致氮、磷含量升高,促进了附近水体氮、磷转化效率和反硝化过程的进行,降低了水体富营养化的风险,但网箱内溶解氧较低,影响水生动物健康生长。试验结果可为稻虾鳝立体综合种养模式的发展与改进提供理论参考。

To probe for the effects of integrated aquaculture model of rice-shrimp-eel on the water environment, eel cages were set up in different positions in the circular groove, and water samples inside the cages, outside the cages and different positions in circular groove were collected and tested every half a month in Xinyang, Henan province from August to October 2020. The results showed that in different periods the dissolved oxygen concentration(DO) inside the cage was always the lowest, DO inside and outside the cages were both lower than that in ring ditch(P>0.05), without significant differences at 4 sampling sites in pH. NH-N levels inside and outside the cage were significantly higher than that far away from the cages(P<0.05), and NO-N and NO-N levels were significantly lower than that far away from the cages(P<0.05). TN and TP levels inside and outside the cage were higher than those in other sites. TN levels showed an upward trend and TP levels showed a downward trend, TN and TP in the ring ditch far away from the cage showed an upward trend. The results showed that the integrated aquaculture mode of rice-shrimp-eel led to enhance N and P levels in the water, promoted the conversion efficiency of N and P in the nearby water as well as the process of denitrification, and reduced the risk of eutrophication in the water, but the low dissolved oxygen in the cage affected the healthy growth of aquatic animals. The findings can provide a theoretical reference for the development and improvement of integrated aquaculture model of rice-shrimp-eel.