绿狐尾藻和空心菜对模拟池塘养殖尾水的净化效果分析

Purification effects of Myriophyllum elatinoides Gaudich and Ipomoea aquatica Forsk in simulated pond culture tail water

  • 摘要: 【目的】探究绿狐尾藻(Myriophyllum elatinoides Gaudich)和空心菜(Ipomoea aquatica Forsk)在漂浮环境培养条件下对不同氮磷水平养殖尾水的适应性及对氮磷营养的吸收和去除效果,为促进2种植物在池塘养殖尾水处理中的推广应用提供参考。【方法】以绿狐尾藻和空心菜为供试植物,设总氮(TN)和总磷(TP)浓度分别为5、10、15 mg/L和1、2、3 mg/L的低(A)、中(B)、高(C)3组模拟养殖尾水,比较2种植物在培养42 d时的生物量、氮磷累积量,以及对水体氮磷的去除能力。【结果】绿狐尾藻在A、B、C组持续生长42 d,其42 d净增生物量和氮磷累积量随生长时间延长、水体氮磷浓度增加而增加,最大值出现在C组;空心菜在A、B、C组正常生长28 d,其42 d净增生物量和氮、磷累积量随水体氮磷浓度增加而下降,最大值出现在A组。在42 d的试验期内,绿狐尾藻对水体氨氮(NH4+-N)、TN、活性磷(SRP)和TP的去除率最高,氮磷去除效果随水体氮磷浓度增加而上升且去除氨氮能力最强,最大值出现在C组;空心菜的氮磷去除效果随水体氮磷浓度增加而降低,且28 d后植株生长和去除能力下降。植物氮磷吸收贡献率结果显示,3组模拟养殖尾水中,绿狐尾藻植物吸收的氮磷贡献率介于33.65%~99.82%,高于空心菜的2.34%~62.21%。绿狐尾藻对低、中、高氮磷水平模拟养殖尾水的适应性优于空心菜;植物吸收是绿狐尾藻去除水体氮磷的主要途径。【结论】绿狐尾藻对水体氮磷的适应范围较广,表现为喜高氮磷,对水体氮磷水平的适应能力、生长和水体净化能力优于空心菜,可用于南方池塘养殖尾水的长期净化,应用潜力优于空心菜。空心菜的生长和对水体氮磷的去除效果随水体氮磷浓度增加而降低,应用于夏秋季池塘养殖尾水处理时宜定期收割以保证净化效果。

     

    Abstract: 【Objective】 To explore the adaptability of Myriophyllum elatinoides Gaudich and Ipomoea aquatica Forsk to aquaculture tail water with different nitrogen and phosphorus levels under floating environment culture conditions, as well as the nutrient uptake and removal effects of nitrogen and phosphorus, and to provide reference for promoting the promotion and application of the two plants in pond culture tail water treatment.【Method】M. elatinoides Gaudich and I. aquatica Forsk were selected as test plants. Three groups of low(A), medium(B) and high(C) with total nitrogen(TN) and total phosphorus(TP) concentrations of 5, 10, 15 mg/L and 1, 2, 3 mg/L were set to simulate aquaculture tail water respectively. The biomass, nitrogen, phosphorus accumulation and nitrogen, phosphorus removal capacity of the two plants at 42 d were compared.【Result】 M. elatinoides Gaudich continued to grow for 42 d in groups A, B and C. Its 42 d net biomass, nitrogen and phosphorus accumulation increased with the increase of growth time and water nitrogen and phosphorus concentration, and the maximum appeared in group C. I. aquatica Forsk grew normally for 28 d in groups A, B and C, its 42 day net increased biomass and nitrogen and phosphorus accumulation decreased with the increase of nitrogen and phosphorus concentration in water, and the maximum values appeared in group A. During the experimental period of 42 d, M. elatinoides Gaudich had the highest removal rates of ammonia nitrogen(NH4+-N), TN, active phosphorus (SRP) and TP. The removal effect of nitrogen and phosphorus increased with the increase of nitrogen and phosphorus concentration, and the removal ability of ammonia nitrogen was the strongest, and the maximum value appeared in group C. The nitrogen and phosphorus removal efficiency of I. aquatica Forsk decreased with the increase of nitrogen and phosphorus concentration in water, and the plant growth and removal capacity decreased after 28 d. The contribution rate of nitrogen and phosphorus uptake by plants showed that the contribution rate of nitrogen and phosphorus uptake by M. elatinoides Gaudich ranged from 33.65% to 99.82%, which was higher than 2.34%-62.21% of I. aquatica Forsk. Under the experimental conditions, the adaptability of the two plants to the simulated aquaculture tail water with A, B and C nitrogen and phosphorus levels was the best for M. elatinoides Gaudich, followed by I. aquatica Forsk. Plant absorption was the main way for M. elatinoides Gaudich to remove nitrogen and phosphorus from water.【Conclusion】M. elatinoides Gaudich has a wide range of nitrogen and phosphorus adaptation, which is manifested as high nitrogen and phosphorus, and its adaptability, growth and water purification ability to water nitrogen and phosphorus levels is better than that of I. aquatica Forsk, which can be used for long-term purification of tail water from pond aquaculture in southern China, and the application potential is better than that of I. aquatica Forsk. The growth of I. aquatica Forsk and the removal effect of nitrogen and phosphorus in water decreased with the increase of nitrogen and phosphorus concentration in water body, and it should be harvested regularly when applied to the treatment of tail water of pond aquaculture in summer and autumn to ensure the purification effect.

     

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