Effect Of Fertilization On Improving Efficiency Of Alternating Current (AC) Field Assisted Phytoremediation Of Sedum Alfredii Hance To Metal Contaminated Soil

The problem of heavy metal pollution in farmland is prominent in our country.Through the remediation of Contaminated Farmland soil,the aim is that the public increas grain yield,protects the safety of agricultural productions and maintains public health.because of hyperaccumulative characteristics,Sedum alfredii has been widely used in soil remediation.However,the Sedum alfredii has some shortcomings,such as small plants,slow growth and long repair cycle.The use of plants combined with other remediation technologies?chemical remediation,electric remediation,etc.?has become a new trend.Studies have shown that AC electric field can promote plant growth and plant heavy metal accumulation without changing the basic properties of soil.There are three aspects to improve the efficiency of phytoremediation by AC electric field combined with plants.^[71]?1?The change of soil moisture.?2?The root cell membrane is usually negatively charged^[74].?3?Metabolism.?1?As a whole,application of inorganic fertilizer?ammonium sulfate?at 0.5 V/cm could significantly promote the above-ground metal content and heavy metal accumulation in Sedum alfredii.With the increase of ammonium sulfate dosage,the abililty of accumulation has promoted gradually which Sedum alfredii absords heavy metals.in the first growth cycle of Sedum alfredii,,compared with CK,fresh and dry weight of F1?50mg/kg?and F2?100mg/kg?increased by49.2%-55.33%and 45.27%-61.56%respectively.In the second growth cycle,inorganic fertilizer?ammonium sulfate?still promoted plant biomass as a whole,but decreased as a whole.?2?Under AC electric field?0.5V/cm?,the effects of different organic materials?Potassium Fulvic acid,Astragalus sinicus L.?dosage?0.1%,0.3%,0.5%?on the remediation efficiency of heavy metal Cd contaminated soil in Sedum alfredii were studied.The results showed the addition of two organic materials had a positive effect on the content of organic matter and the content of available heavy metal in soil.the treatment of Astragalus sinicus L.had a better effect on the improvement of organic matter,which is higher 22.15%-23.72%than the control,while 0.5%Astragalus sinicus L.has obvious effect on improving the available heavy metals in soil,copper,zinc,lead and cadmium increased by 11.47%-28.02%compared with the control.Potassium fulvic acid treatment was beneficial to the increase of soil acid extractable Cd,which was 2.54%³.25%higher than the control,while Astragalus sinicus L.had less effect on soil acid extractable Cd.At the same time,two kinds of organic materials promoted the growth of Sedum alfredii,and the effect of 0.3%was the prominent,which increased 124%¹52%compared with the control treatment without organic materials.Under electric field,both two organic materials could improve the remediation efficiency of Sedum alfredii to heavy metals in soil,and Potassium Fulvic acid was better.Under the application of 0.1%,0.3%and 0.5%,the Cd accumulation of heavy metals in the aboveground parts of Sedum alfredii was increased.The cumulative yield increased by 61.54%,265.44%and 45.63%respectively,while the Astragalus sinicus L.increased by 73.02%,73.50%and 2.94%respectively.