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The Driving Effect And Mechanism Study Of Rice On Form Transformation Of Zn In Soda-Saline-alkali Soil

Posted on:2019-08-27Degree:MasterType:Thesis
Country:ChinaCandidate:N ZhangFull Text:PDF
GTID:2370330596455641Subject:Environmental Engineering
Abstract/Summary:PDF Full Text Request
This study focused on the typical Soda saline-alkaline soil in the village of Jianbala Village,Taohaotai Town,Songyuan City,Jilin Province.Samples of tillage layer(Ap),plough bottom layer(P)and soil layer(C)in different salt-alkaline soils of different planting years were collected,and soils from adjacent uncultivated abandoned grasslands were used as controls.The Tessier continuous extraction method was used to study the driving role of planting in transformation of zinc forms in soil.The purpose is to provide a theoretical basis for the regulation of zinc nutrition in paddy fields under saline conditions and reduce the risk of heavy metal pollution in soil.The results of the study are as follows:(1)After the improvement of rice cultivation in saline-alkali land,the contents of available-state zinc such as available zinc,zinc exchangeable,and organic-bound zinc have been significantly increased at the first year of rice cultivation.The contents of non-biologically active zinc such as carbonate-bound zinc,zinc oxide-bound zinc,and residual zinc have been increased,and they have been most effective in the first year of rice breeding.The promotion effect of seed rice on the Zn content of effective Zn,exchangeable Zn,organically bound Zn and other biologically effective states decreased with the increase of the profile level.(2)After the salt-alkali soil was improved with planting,the physiochemical environmental indicators of the soil related to the zinc form all changed significantly.the pH of all the layer profiles showed a continuous decline.The content of soil organic matter after the improvement of rice is higher than that of abandoned grassland.In the first 20 years,rice has been on a continuous upward trend,and after 20 years,it has gradually declined.The content of organic matter in the soil profile of the layer is represented as: Layer Ap>Layer P>Layer C.In addition to the slight decrease in total N content in the first year of the Ap layer,the total N content in all other layers showed a continuous upward trend.Soil clay content rapidly increases at 1 year of rice cultivation and changes slowly after 1 year.Soil carbonate content continues to decline.The other available nutrients,total nutrients,and CEC did not change significantly.(3)The results of correlation analysis showed that the correlations between various forms of zinc and soil physical and chemical environments reached significant or extremely significant levels.Among them,the correlation between pH,organic matter content and various forms of zinc is the highest,and the soil pH and organic matter content are the main factors driving the mutual transformation of different forms of Zn in the soil.Saline-alkali soil can significantly reduce the pH of soil and increase the organic carbon content after being improved by the seed rice,which in turn drives the conversion of the non-biologically effective Zn to the biologically effective Zn.
Keywords/Search Tags:soda saline-alkali soil, planting year, forms and transformation of zinc, soil physical and chemical environment
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