The Availability Of Passivators To Cadmium In Farmland Soil And Different Rice And Wheat Arieties Effects Of Cadmium Absorption

In recent years,heavy metal pollution in farmland soil has become increasingly serious,which has affected the normal growth of crops.Excessive heavy metals in soil lead to excessive absorption of heavy metals into crops,which enter human body through food chain and harm human health.In order to ensure the quality and safety of agricultural products from the source,and realize the safe use of cadmium pollution in farmland soil,the application of tianxiang soil conditioner(TX),ningliang soil conditioner(NL),biochar(BC),lime(Li),silicon fertilizer(Si)and other 5 passivating agents on farmland and indoor potted plants was studied.Effects on soil pH,soil fertility(organic matter,nutrient elements),Cd available state content,different forms of Cd and the persistence effect of inactivators,and explore the effects of inactivators on the yield of different rice and wheat varieties,as well as rice and wheat.According to the influence of Cd absorption by organs,inactivating agents with better Cd-reducing effect and rice and wheat varieties with less Cd absorption by grains were screened out.The main results obtained are as follows:(1)In the rice season experiment,the application of passivation agent reduced the effective content of soil Cd,and the application of TX,NL soil conditioner,biochar,lime,and silicon fertilizer treatments reduced 59.4%,29.9%,22.8%,22.4%,and 22.4%,respectively,compared with the control treatment.54.4%.The application of passivators reduces the soil Cd unstable state content(weak acid extraction state and reducible state),and increases the Cd stable state content(oxidizable state and residue state).Applying different inactivators to varying degrees inhibited the absorption of Cd by the roots,stems and grains of each rice variety and increased the yield of each rice variety.Among them,the application of TX soil conditioner had the best effect.It significantly reduced the Cd content in the grains of Nanjing 9108,Yangjing 103,Yangjing 805,and Huaidao 5 by 80.5%,82.8%,65.4%,and 55.6%,respectively.The yield of rice varieties increased by 29.2%,9.2%,18.6%,and 14.2%respectively.(2)In the wheat season test,the application of passivator to reduce the effective content of soil Cd,the application of TX,NL soil conditioner,biochar,lime,and silicon fertilizer treatments reduced by 66.8%,48.6%,12.4%,36.4%,and 36.4%,respectively,compared with the control treatment.70.8%.The BCR results show that the application of passivation agent reduces the content of weak acid extraction state and reducible state,and increases the content of oxidizable state and residue state.The application of inactivating agents inhibited the absorption of Cd by the roots,stems and grains of various wheat varieties while increasing the yield of each wheat variety.Among them,silicon fertilizer and TX soil conditioner are more effective.Si treatment significantly reduces Cd of Ningmai 13,Yangfumai 4,Yangmai 15,Yangmai 23 and Mingmai grains by 54.2%,51.5%,58.7%,44.8,respectively.%,47.1%,increase the output by 11.1%,3.5%,7.7%,10.9%,2.4%respectively.(3)Applying passivation agent in the rice season and not applying any treatment in the wheat season will increase the soil pH and organic matter,but will reduce the effectiveness of reducing soil Cd.For long-term reduction of soil Cd availability and suppression of Cd accumulation in wheat roots,stems and grains,the best effect is Si treatment,followed by TX treatment.(4)In the rice season experiment,only planting Huaidao 5 and Yangjing 805 combined with TX soil conditioner treatment,the grain Cd content was 0.163 mg/kg and 0.147 mg/kg,which met the safety and quality standards of agricultural products.In the wheat season experiment,when both Ningmai 13 and Yangfumai 4 were combined with silicon fertilizer or TX soil conditioner,the Cd content in the grains was low,but both exceeded the safety and quality standards for agricultural products.Two rice varieties,Huaidao 5 and Yangjing 805,Ningmai 13 and Yangfumai 4 are recommended as low-heavy metal accumulation rice and wheat varieties adapted to the central Jiangsu region,and can be combined with TX soil conditioner or silicon fertilizer.