Effects Of Different Fertilization Methods On Soil Physical And Chemical Properties And Organic Carbon Composition

In recent years,the agro-pastoral ecotone in Inner Mongolia has been seriously degraded,and the improvement and fertilization of soil have aroused people's concern.In this paper,the crop yield,soil organic carbon components and soil physical and chemical properties were compared by studying the different methods of returning straw and biochar returning.Six treatments were set in this experiment,straw mulching,straw was directly returned to the field,organic fertilizer and biochar application,only chemical fertilizer was applied and no fertilization as a control.Research indicates:1.The crop yields under different fertilizing methods were all improved to varying degrees.The yield of crops treated with organic fertilizer was the highest,followed by straw directly returning and biochar returning,which increased by 13.33%,10.82%and 10.29%respectively,compared with CK treatment.2.Different fertilization measures have certain improvement effects on soil physical properties.The content of soil agglomerates with a diameter of>0.25 mm treated by biochar returning to the field was the highest,with an increase of 14.85%,followed by organic fertilizer returning to the field.Both straw returning and biochar returning to the field can improve the organic matter in the soil,increase the porosity,and enhance the soil water storage capacity.Therefore,the soil water content can be effectively improved,and the straw mulching returning to the field is the best,followed by biochar mulching returned to the field.3.Straw returning and biochar returning to the field can significantly increase the content of available nutrients in soil.The soil treated with organic fertilizer returned to the field had the highest available nitrogen content,followed by straw directly returned to the field for treatment.Under different fertilization measures,the soil available phosphorus was the highest in the soil treated with organic fertilizer,and the second was treated with biochar,which was 78.52%-110.7%and 48.95%-110.44%higher than CK.The highest available potassium content in the soil was treated with organic fertilizer,which was increased by 21.45%-32.03%compared with CK.4.Soil enzyme activities were significantly affected by different fertilizer treatments.Straw mulching treatment significantly increased soil catalase activity,followed by biochar returning to the field,which was 6.15%-13.83%and 3.97%-10.89%higher than CK respectively.Soil sucrase activity also showed:organic fertilizer returned to field>biochar returned to field>straw directly returned to field>straw mulching returned to field>fertilizer>CK.The urease activity in the soil was the highest in the treatment of biochar,and the treatment of organic fertilizer was the second,which increased by 16.19%-21.33%and 7.32%-18.73%,respectively compared with CK.5.Straw mulching and biochar mulching can significantly increase the content of organic carbon and its components in soil.The total organic carbon and microbial biomass carbon content of the soil treated with biochar returned to the field were the highest,followed by organic fertilizer,which increased by 36.02%-41.83%,27.96%-40.88%and 48.39%-58.76%,44.26%-54.93%respectively compared with CK.The overall trend of soil easily oxidized organic carbon and light group recombinant organic carbon is consistent,which basically showed that the effect of organic fertilizer returning to field and biochar returning to field was the best.The soil microbial biomass carbon content of the biochar returning field was the highest,followed by the organic fertilizer returning to the field.The overall performance was:biochar returning to the field>organic fertilizer returning to the field>straw directly returning to the field>straw mulching returning field>fertilizer>CK.