Research And Restoration Of Sewage Irrigation Soil In Xi'an

In this research,we studied the soil of the farmland and its corresponding three kinds of cauliflower,radish and cabbage in the west Village,Xi'an,and selected the background of the appleland area in the same area with groundwater irrigation.Soil water composition,pH,nitrogen,phosphorus,organic matter,catalase activity and the corresponding three plant height and leaf area were used to evaluate soil quality and crop damage,respectively,and then the total soil And its corresponding three kinds of crops in different parts of the heavy metal content,and finally the occurrence of heavy metals by Tessier definition extraction method and the use of Nemero comprehensive pollution index method to assess the status of heavy metal pollution.The results showed that the content of heavy metals in the study area was significantly exceeded,and the accumulation intensity of different elements in the soil was obviously different,and the order was Cd>Zn>Pb>Cu.There were significant differences between the four heavy metal contents and the non<0.01),radon(Raphanus sativus)and cauliflower(Ottelia acuminata)had good enrichment and accumulation effect on Cd and Cu,respectively.The remediation effect of three crops on the soil of Xi'an irrigation area was radish>cabbage>Brassica chinensis),The accumulation of heavy metals in different crop organizations was root>stem,leaf>fruit.The proportion of heavy metals in four soils was significantly different,respectively,radish>cauliflower>cabbage>apple,indicating that radish and cauliflower were more easily absorbed by soil heavy metals.The results showed that the limestone mineral content was 1%,2%and 4%,and the effect of limestone on the soil heavy metal was studied.The plant height,Leaf area and yield,and the contents of heavy metal in different parts of Chinese cabbage were determined.The basic physical and chemical properties,heavy metal content and morphological changes of the soil were determined.The results showed that the limestone can affect the physicochemical properties of the soil and reduce the bioavailability of the heavy metal elements in the soil through the passivation effect,so as to achieve the desired repair effect.A certain mass fraction of limestone to promote the growth of plants,more than the maximum tolerance of plants,it plays a role in inhibition.When the mass fraction of limestone is small,the plant height and leaf area of the plant are obviously promoted.The concentration of higher quality fraction is not conducive to plant growth.The effect of low concentration of limestone on the activity of catalase,the activity of superoxide dismutase,the content of free proline and the content of malondialdehyde in Chinese cabbage were not significant.In the limestone soil with the mass fraction of 2%It was found that the absorption of heavy metals was much lower than that of the unmixed and added 1%mass fraction,and the heavy metals Zn and Cd were reduced by 32.7%and 56.01%,respectively.While the content of peroxidase and superoxide dismutase in cabbage was significantly decreased,while the content of malondialdehyde and free proline increased continuously.The addition of different mass fraction of limestone can reduce the degree of freeing of heavy metal elements in soil and crops.In summary,according to the different crops of different heavy metal absorption and transformation of the difference,in the heavy metal pollution area soil selection of appropriate crop species for scientific cultivation.Which can improve the yield and quality of crops,and have good ecological and economic benefits.It also provides the theoretical basis for the assessment of soil environmental quality and the selection of crops in the sewage irrigation area of Xi'an.