Research On Heavy Metals Transportion And Enrichment Properties In The Legume Forages

In recent years,because of the fast growth, large biomass, taken pasture as a heavy metalsoil pollution phytoremediation plant are increasingly enjoyed by people. The north pasturecan replace part of the feeding grain of livestock and poultry, and also have good ecologicalprotection and restoration function. Heavy metals are a common pollution in the environment.For soil pollution in agricultural areas, having environmental quality assessment andanalysising the absorption and transportation of plant in heavy metals soil is necessary. Thispaper is to determinate the several heavy metals(Cu, Zn,Fe, Mn,Cr, Cd, Ni and Pb) contentof the legume pasture alfalfa (Medicago sativa L.), Lotus corniculatus (Lotus cornioulatus L.),crown flowers (CoronillavariaL.) and pasture sweet pea (Lathyrus pratensis L.) and its soil inthe Northwest Agriculture and Forestry University grassland experimental field hese.According to the national soil quality of the environment and feed hygiene standardsassessment,to measure the extent of heavy-metal polluted soil and the security of the forage.Comparing the absorption and transportion capacity of the pasture, and providing the basis forselecting the low accumulation grass used for forage production and enriched grass for thepollution of pasture and urban green space. The main conclusions are as follows:1、 The heavy metal content of the upper and roots pasture and its absorption andtransportation capacityCollecting samples and measuring the heavy metal content of the upper and the rootspastures by atomic spectrophotometer, we found that the rangeland sweet pea, whethermeasured in the aerial parts or roots,had the strongest absorptive capacity of Cu, Zn,Fe,Mn,Cr, Cd, Ni and Pb, the heavy metals content of the aerial parts were11.143,28.951,218.419,69.209,0.397,20.825,9.178and15.399, roots were28.389,24.747,1563.535,102.302,0.767,42.013,15.945and17.023; different pasture havedifferent transfer coefficient with the heavy metals from the roots to the ground, the mostoutstanding performance was alfalfa, alfalfa transfer coefficient for Zn,Cd,Ni and Pb weregreater than1, has the stronger transporting capacity, were1.0953,1.1422,1.0551and1.0060,and its large biomass of the aerial part should be consided for soil remediation of heavy metalpollution.corniculatus had highly transportation capacity witn Cd, ransfer coefficientwas1.3085, belonging to the accumulation plant for Cd; small crown flowers and pasturesweet pea zinc have strong transport capacity for Zn, the transfer coefficient were1.4404and1.0688, respectively, belonging to the accumulation plant for Zn, although their coefficient were lower than1for Pb, belonging to the exclusion plants, the transfer coefficient as high as0.9938and0.9046respectively, thus their also had a higher transport capacity.2、The heavy-metal contents of pasture,s soil and soil environmental quality assessmentMeasuring the soil samples found that grazing land sweet pea heavy metals of Cu, Zn, Fe,Mn, Cr, Ni and Pb in soil had the maximum uptaking, respectively126.06,115.88,29138.45,725.20,64.80,63.15and34.69; With the evaluation of the singlepollution index,showed that the average index of Cu, Zn, Cd, Cr, Ni and Pb were1.2538,0.3688,2.3833,0.2385,1.0003and0.0953, in the order of: Cd> Cu> Ni> Zn> Cr>Pb.So Cd had the highest pollution index, was moderate pollution; Cu and Ni had higherpollution index, were light pollution.With Nemerow Composite Pollution Index, the pollutionindex of the alfalfa, Lotus corniculatus, crown flowers and pasture sweet pea wererespectively1.8129,1.9834,1.7573and1.6411, the measured soil and crop were reached tothe light level of pollution. With forage safety evaluation test to measure the heavy metals offour forage showed that Cu and Zn were not excessive, in line with the feed safety and healthstandards; the content of Pb and Cd had been exceeded and could not stand alone as the dietof livestock; addition to the content of Lotus corniculatus not exceeded for Cr, other forageswere exceeded, ccould not stand alone as the diet of livestock.