The Influence Factors Of Soil Cadmium Availability And The Control Effects Of Different Amendments

In this study,we use fitting analysis to discuss the relationship between soil chemical properties and Cadmium availability in different regions of China.Through adding different amendments to artificially medium cadmium polluted soil and paddy soil contaminated by industrial Cadmium,we analysis the control effects of different amendments on soil chemical properties and cadmium availability toexpected to find technical methods to mitigate cadmium hazards in soil utilization.The main research results include the following three parts:Soilfrom 18 different regions are made into moderately cadmium polluted soil.We use fitting analysis to discuss the relationship between soil chemical properties and available Cadmium,Cadmium forms.We conclude that soil pH,soil organic matter,total nitrogen are related to the soil cadmium availability in different degrees.The soil pH is most significant.As the soil pH increases,available Cadmium shows a decreasing trend,acid extractable Cadmium is inversely proportional to the soil pH,reducible Cadmium proportion with the change of soil pH is small,oxidizable Cadmium increases with the rising of soil pH,residual Cadmium is inversely proportional to soil pH.The Jiangsu Yixing(loess)and Jiangsu Huaian(Tidal loess)Cadmium polluted soil culture experiment shows that the content of available Cadmium can be reduced to different extent by different amendments.Among them,the consequence of Yixing soil is superior toHuaian.On the Yixing polluted soil,the regulation effect of straw charcoal is the bestand the pig manure charcoal control effect on Huaian polluted soil is better.In addition,after adding different amendments,theacid extractable Cadmium in the soil decreases,while the content of the residual Cadmium increases significantly.In the condition of this experiment,pig manure charcoal significantly improves the soil pH and organic matter of Yixing soil,and on the Huaian soil,the effect of straw charcoal is more significant;The CEC control effect of straw carbon is better than pig manure charcoal.In terms of soil nutrient regulation,the effect of pig manure charcoal is better.The different amendments controlling rice pot soil experiments is further demonstrated that the application of amendment can effectively reduce the content of the available Cadmium of soil.The combination of straw charcoal and attapulgite reduces the maximum amount of soil avaliable Cadmium content,which reduces 18.29%.After applying the amendment,the content of acid extractable and reducible Cadmium in soil decreased inordinately,while other forms increases.The control effects of different amendments on soil chemical properties are also diflerent.All treatments increase soil pH.The increase trend of soil organic is the same with pH,in addition to 1%straw charcoal,Cadmium reduction organic fertilizer,water-soluble organic fertilizer changes available p indistinctively,the rest of the treatment can obviously improve the content of available p.The highest soil total nitrogen content is straw charcoal and attapulgite combination and single application of straw charcoal which achieves 1.36 g/kg,the rest has no significant impact on soil total nitrogen content;All treatments improve CEC of the soil,and the highest value is 51.85cmol/kg of attapulgite,which is 8.70%higher than CK.All amendments can obviously promote rice growth and development,improve rice biomass.Bionass carbon combined with attapulgite is better,it can achieve a significant increase level.The effect of pig manure charcoal on tillering rate of rice is more obvious,especially that in combination with attapulgite increases 26.94%.The application of various amendments not only promote the growth of rice and improve the soil ecological environment,but also inhibit the absorption of Cd in the soil.The application of amendments can reduce the Cadmium content in rice and underground parts,which improve the safety of rice production.The Cadmium content of underground parts decrease 3.22%-54.89%and the ground parts decrease 14.09%-80.63%,which reach a significant level.Through the above conclusions,we can conclude that in tihie Yixing Cadmium polluted paddy soil,the combination of biomass charcoal and physical amendments materials like attapulgite can significantly reduce the availability of cadmium in soil,and also improve rice yield and reduce the absorption of cadmium to rice.At the same time,combined with the conclusion that pH has the greatest impact on the availability of Cadmium in the first part of the study,this study also provides a theoretical basis for increasing the availability of Cadmium control in Jiangsu and most of the acid soils in southern China and using biomass improved materials in the process of rice production.All the amendments used in this paper,according to local conditions,make full use of local materials and conform to the actual situation of zero growth of chemical fertilizer in agricultural production.The purpose of this study is to find an economic and effective way to improve soil Cadmium pollution and provide new ideas for ensuring the safety of modem agriculture and food crops.