Research On Technology Of Phytoremediation Of Farmland Drainage

The farm chemicals (mainly included chemical fertilizer and pesticides) are widely used in the field of the ecological system,which lead the water contained a lot of N&P and other nutrients and it also contains little of the pesticide during farmland drainage. It can cause water eutrophication and pesticide residue pollution to the water after these matters followed into the surface water. This can be a threat to drinking water for people and livestock and lead to the death of the aquatic animals. This research studied six common aquatic plants by introducing a space technology through analogue experiment. There are Oenanthe javanica,Ipomoea aquatica Forsk,Eichhornia crassipes,Lemma Paucicostata,Spirodela polyrrhiza and Azolla imbircata the absorption and purification ability of TN,TP and Difenoconazole in the artifical farmland drainage. The result showed that:six experimental aquatic plants have great absorption and purify capacity to TN,TP and Difenoconazole.The ability to remove and purify TN is as follow: Ipomoea aquatica Forsk>Oenanthe javanica>Eichhornia crassipes>Azolla imbircata>Spirodela polyrrhiza>Lemma Paucicostata.The ability to TP is as follow: Oenanthe javanica>Ipomoea aquatica Forsk> Eichhornia crassipes>Spirodela polyrrhiza> Azolla imbircata>Lemma Paucicostata.The ability to Difenoconazole is as follow:Oenanthe javanica>Eichhornia crassipes>Ipomoea aquatica Forsk> Spirodela polyrrhiza>Azolla imbircata>Lemma Paucicostata.Considering Oenanthe javanica and Ipomoea aquatica Forsk can be eaten as vegetable,and Lemma Paucicostata and Azolla imbircata can feed farm animal, Taking Oenanthe javanica and Ipomoea aquatica Forsk as the main aquatic plants and also taking the different aquatic plants growing season characteristics and ecological habits and ecosystem diversity and stability into consideration, The author tried to build 4 binary complex plant Systems based on "Oenanthe javanica-Azolla imbircata","Ipomoea aquatica Forsk-Azolla imbircata","Oenanthe javanica-Lemma Paucicostata" and "Ipomoea aquatica Forsk-Lemma Paucicostata",And apply it to the remediation and treatment of the farmland drainage, so it can not only absorb nitrogen and phosphorus to produce Oenanthe javanica and Ipomoea aquatica Forsk ,and also remediate the remains of farm pesticide residne-Difenoconazole .The results showed that the above 4 binary compound ecological systems can further improve the absorption and purification ability of TN TP and Difenoconazole .The purification ability of Difenoconazole increased almost 1 time.