Effects Of Dairy Slurry Application On Soil Salt Under Wheat-maize Rotation In North China Plain

The adjustment of agricultural structure and the promotion of agricultural industrialization have made the rapid development of large-scale dairy farming in China.However,a large number of waste generated in the production process is difficult to deal with.Unreasonable emissions of the dairy slurry can cause eutrophication of surface water easily and contaminate the groundwater.This thesis studied the change in the soil salt and the degree of the soil salinization,to guide the reasonable utilization of the dairy slurry in wheat-maize rotation by the experiment with the application of the dairy slurry and the chemical fertilizer from 2014 to 2016.The main results were as followsThe EC of the soil increased under the application of the dairy slurry than the EC of the original soil(before the experiment began in 2012),which indicated that the ulitization of the dairy slurry made the accumulation of the salt in soil.In the range of soil from 0 to 200 cm,the treatment with the application of the dairy slurry was significantly different from the contrast CK,but not reaching the level of salinization.The treatment with the application of the chemical fertilizer exceeded the treatment with the application of the dairy slurry,which indicated that the accumulation of the salt and the soil salinization under the application of the dairy slurry was lower than the application of the chemical fertilizer.In the range of soil from 0 to 200 cm,the EC of the soil in all the dairy slurry treaments showed the trend that it increased firstly and decreased later,and the maximum emerged in the soil depth from 40 to 120 cm.The pH of the soil increased under the application of the dairy slurry than the pH of the original soil.The pH of the soil was positive correlated with the concentration of the dairy sluury in different dairy slurry treatments.In the range of soil from 0 to 200 cm,the pH of the soil in all the dairy sluury treaments showed the trend that it increased firstly and decreased later,and the maximum emerged in the soil depth from 40 to 120 cm.The soluble Na+ and Mg2+ content in the soil increased under the application of the dairy slurry.content in the soil increased than that in the original soil,and the soluble K+ and Ca2+ content in the soil performed irregular in different periods.In the different dairy sluury treatments,the soil soluble cation content was positive correlated with the dairy slurry concentration.In the range of soil from 0 to 200 cm,the soluble Na+ and K+ content in the soil of all the dairy slurry treaments showed the trend that it increased firstly and decreased later,the soluble Ca2+ and Mg2+ content in the soil of all the dairy slurry treaments showed the trend that it decreased firstly and increased later.In the range of soil 0-200 cm,the soluble Cl-content increased under the application of the dairy slurry than it in the original soil.In the different dairy sluury treatments,the soluble Cl-content in the soil was positive correlated with the dairy slurry concentration.The content was positive correlated with the dairy slurry concentration.Under the influence on the rainfall and irrigation,the soluble Cl-content in the 0 to 200 cm soil showed the distribution that the higher content was observed in the top soil and the lower content was in the subsoil.The soluble SO42-content in the soil deceased under the application of the dairy slurry than it in the original soil.In the range of soil 0-200 cm,the soluble SO42-content in the soil of all the dairy slurry treaments showed the trend that it decreased firstly and increased later,which was affected by soil pHThe results showed that the soil salt increased in short period under the application of the dairy slurry and the salt accumulation was not obvious.The risk of soil salinization under the application in long period was still to be studied.