On the farmland soil remediation by planting day lily in Xiaodian sewage irrigation area near Taiyuan

The present paper is inclined to report the experimental results of our sampling investigation on the feasibility of farmland soil remediation by planting day lily in Xiaodian sewage irrigation area near Taiyuan City.The results of our experiments show that the soil pollutants were related to the sampling sites.In the Taiyu water-releasing canal(TT),Beizhang water-releasing canal(BT) and the eastern trunk canal(DG),the pollution concentrations of As,Cr,Cd and Pb in the soil were found decreasing in the order below: BTTTDG;the content concentration of Hg differed in the following order: DGTTBT;and the content of polycyclic aromatic hydrocarbons(PAHs) in the soil was found decreasing in the following descending order: BTDGTT,though there exists a significant difference among the different irrigation areas with the concentrations of As,Hg,Cr,Cd and PAHs in the soils concerned.However,the content concentrations of Pb in the soils of TT,BT and DG irrigation areas didn't prove obvious.The content concentrations of As,Cr,Cd and Pb in the three parts(fleshy root,stem-leaf,and flower) of the day lily flower differ in the next order: BTTTBG.The pollution degrees in the different parts of the day lily flower also proved to be various in the following descending order: fleshy rootstem and leafflower.The heavy metal concentrations laden in the said flower pedals were found significantly lower than in the fleshy root,stem and leaves,however,no significant difference of the pollutants was found between the fleshy root and the stem-leaf.Moreover,the pollutants in the fleshy root and stem-leaves tends to decrease in the following order: branch canal weir main canal dam ridge.Of the different planting places,the mutual relation of the content concentrations of Cd,Hg and PAHs in the flower doesn't seem to be very regular.On the whole,the biomass of the stem and leaves accounts for more 30% of the total biomass.Therefore,harvesting stem and leaves is likely to reduce the harmful pollutant content.Thus,it can be concluded that it is beneficial and feasible to plant day lily to improve the quality of the farmland soil in the area.