| The salt composition of soda saline-alkali soil is dominated by Na2CO3 and NaHCO3.This type of soil has both salinization and alkalization characteristics.It not only has strong alkalinity,but also has poor physical and chemical properties,which severely restricts local agricultural production.The application of ameliorants to improve saline-alkali soil has been around for a long time.With the increasing awareness of environmental protection,the development and utilization of efficient and environmentally-friendly ameliorants has gradually become a hot spot of concern.Biochar and polyaluminum ferric sulfate are simple to prepare and have a wide range of materials,and they are a kind of reuse of agricultural and industrial wastes.However,as far as the current research is concerned,the application of biochar mostly focuses on acidic soils or low-salt to medium-salt soils,but but the research on soda saline-alkali soil is insufficient;polyaluminium sulphate is widely used in water treatment,and its application in the improvement of saline-alkali soil has rarely been reported.In this study,soda saline-alkali soil was used as the research object.In view of the physical and chemical properties of soda saline-alkali soil,biochar and polyaluminum ferric sulfate were used as ameliorant.The effects of different dosage of two ameliorants on the physical and chemical properties of soda-saline soil were studied through a soil column leaching experiment.The aim is to provide data reference for the application and popularization of biochar and polyaluminum ferric sulfate in the improvement of soda saline-alkali soil,as well as the rational development and utilization of soda saline-alkali soil resources.The research results are as follows:(1)The application of polymeric aluminum ferric sulfate can significantly reduce the pH of the eluent,and the application of biochar has little effect on the pH of the eluent.The application of biochar and polymeric aluminum ferric sulfate can significantly increase the content of Na+,K+and Mg2+ in the eluent.With the increase of leaching times,the pH of the leaching solution will increase accordingly.(2)The application of biochar and polyaluminum ferric sulfate can significantly reduce soil bulk density of soda saline-alkali soil,increase soil porosity,and significantly increase saturated water holding capacity,capillary water holding capacity and field water holding capacity of soda saline-alkali soil.When the application amount of biochar is 1%,and that of polyaluminum ferric sulfate is 2%,the saturated water holding capacity,capillary water holding capacity and field water holding capacity of soda saline-alkali soil were the highest.(3)The application of polyaluminum ferric sulfate significantly reduced the pH and EC of soda-saline alkaline soil;while the application of biochar slightly increased the pH of the soil and significantly increased the EC of soil.The application of biochar increased the content of water-soluble Na+,K+,Ca2+and Mg2+in soda saline-alkali soil and reduced SO42-content,but its effect on CO32-and HCO3-content was not significant.The application of polyaluminum ferric sulfate significantly reduced the water-soluble Na+,K+,Cl· CO32-and HCO3-content of soda saline-alkali soil,but it significantly increased the SO42' content.(4)The application of biochar significantly increased the cation exchange capacity(CEC)of soda saline alkaline soil.And the application of polyaluminum ferric sulfate can effectively reduce the sodium adsorption ratio(SAR)and alkalinity(ESP)of the soda saline-alkali soil.Combined with the effects of biochar and polyaluminum ferric sulfate on the physical and chemical properties of soda saline-alkali soil,the physical and chemical environment of soda saline-alkali soil was improved better by mixing the two ameliorants.When the application amount of biochar was 1%and that of polyaluminum ferrie sulfate was 2%,the best improvement effect was obtained. |
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