Effects Of Common Biochar And Acid-modified Biochar On Soil Water And Salt Distribution And Spinach Growth In Tidal Flat Area

With the continuous development of society and economy,China's arable land resources are increasingly scarce.The reclaimed tidal flat land will become an important reserve land resource in China,and the reasonable improvement and utilization of it is conducive to ensuring China's food security.Based on this,this study took the soil in tidal flat area as the research object,and set up 7 treatments including 2%,4%,8%(A1,A2,A3)of common biochar,2%,4%,8%(B1,B2,B3)of acid-modified biochar and no biochar(CK).Through soil column simulation test and potted spinach test,The effects of common biochar and acid-modified biochar and their application amounts on soil physicochemical properties and spinach growth in tidal flat area were investigated,and the main research conclusions were as follows:(1)Adding common biochar and acid-modified biochar can promote soil water infiltration and inhibit evaporation to a certain extent.Under different biochar application rates,the migration distance of soil moisture front and the cumulative infiltration amount were higher than those of the control,and were positively proportional to the application rate.After the infiltration,the soil moisture content of the treatment with biochar increased.A1 treatment reduced the soil salt content of 15-30cm soil.In the process of evaporation,all treatments showed the phenomenon of salt accumulation.Compared with the control,the addition of biochar reduced the soil salt accumulation rate to a certain extent,and the salt accumulation rate of B1 treatment decreased the most,up to 62.10%(2)The addition of common biochar and acid-modified biochar improved soil physical structure,decreased soil bulk density,and increased soil total porosity.Compared with the control,soil water holding capacity and soil available water content were increased under different application amounts of common biochar and acid-modified biochar.The addition of biochar in soil decreased soil pH,and the soil pH of 8%acid modified biochar treatment was significantly lower than that of the control.However,the soil desalination rate decreased with the increase of biochar application amount,and too high addition amount would affect the soil desalination effect.(3)The contents of organic matter and organic carbon in soil increased,and were directly proportional to the amount of biochar application.The soil nitrate nitrogen content under the higher application amount of common biochar was significantly higher than that of CK,indicating that the addition of common biochar could effectively improve the soil nitrate nitrogen level.(4)The addition of common biochar and acid modified biochar increased the maximum daily net photosynthetic rate of spinach,promoted its growth and development,and improved the yield and quality of spinach.Among them,spinach yield reached the maximum when acid modified biochar was added with 2%,soluble sugar and soluble protein content reached the highest and nitrite content was the lowest when acid modified biochar was added with 4%.(5)Based on the pot experiment data,six evaluation indexes(maximum available water content,desalination rate,soil organic matter content,leaf area index,maximum net photosynthetic rate and yield)were selected to evaluate the related treatments by using the grey multi-dimensional comprehensive membership evaluation method.The results showed that,B2 treatment(4%acid modified biochar)was the best biochar application scheme for soil in tidal flat area under the experimental conditions.