Effect Of Moisture And Phosphate On Available Heavy Metals In Soil And Accumulation Of Echinodorus Osiris

In order to control the hazard of heavy metals in soil, water and phosphates regulation have been widely researched these years. To find the effect of different water(flooded and 60% field moisture capacity-60%FMC) and phosphate(calcium dihydrogen phosphate-CDP and diammonium hydrogen phosphate-DHP) treatments on the available content of Cd, Pb, Zn and As, the growth and the accumulation of Echinodorus Osiris, incubation and room culture experiment were conducted, based on previously research of Echinodorus Osiris. The main results were as follows:(1) Flooding and phosphates both reduced the available content of Cd, Pb and Zn, but significantly increased the available content of As in soil. There were no significant difference on the available content of Cd、Pb and Zn in the soil between CDP and DHP under lower applying, but CDP significantly decreased the available content of Cd、Pb and Zn in the soil, while DHP had no remarkable effects on them in incubation experiment, and only significantly redused the available content of Pb and Zn in room culture experiment under higher applying.(2) Flooding and phosphates both significantly promoted the growth of Echinodorus Osiris, but significantly reduced the the content of Cd, Pb and Zn and their enrichment coefficient, while significantly increased the content of As and its enrichment coefficient and the transport coefficient of Cd, Pb, Zn and As of Echinodorus Osiris. Among them, the dry weight of Echinodorus Osiris under flooded treatments were all more than 1 times, and transport coefficient of Cd, Pb, Zn, and As of Echinodorus Osiris were 1.8 times,1.6 times, 1.4 times and 5 times than 60% FMC, respectively. Though Echinodorus Osiris had a higher transport coefficient of Cd, Pb, Zn and As with lower applying of DHP under flooding, there’s no significant difference in the effects of phosphate fertilizer on the growth, heavy metals content and enrichment coefficient of Echinodorus Osiris between CDP and DHP under lower applying. With higher applying, CDP still increased the growth of Echinodorus Osiris, but also reduced the content of Cd, Pb and Zn more, as to DHP, it had little effect on the growth of Echinodorus Osiris, but it kept a higher level of the content of Cd, Pb and Zn and their transport coefficient.(3) Correlation analysis showed that the available content of Cd, Pb and Zn in soil were closely related to soil pH, and the available content of As in soil was very significant positive correlation with the available content of P in the soil. As to Echinodorus Osiris, the content of Cd, Pb, Zn and As in shoot were significantly positively related with their available content in the soil, respectively, which indicated that by changing soil pH and the available content of P water and phosphorus can change the available content of heavy metal, and then influence the accumulation of heavy metal in Echinodorus Osiris.In conclusion, flooding and phosphorus reduced the content of Cd、Pb、Zn and improved the available content of As, and this may mainly through alter soil pH and the available content of P. At the same time, they significantly promoted the growth of Echinodorus Osiris, causing the change of enrichment coefficient and the transport coefficient, eventually significant increased the accumulation of heavy metals in Echinodorus Osiris. Due to phosphate dosage, the change of available content of heavy metal and the accumulation of heavy metals in Echinodorus Osiris, we suggest that lower applying of DHP under flooded condition could increase heavy metals accumulation of Echinodorus Osiris.