Effects of Combined Application of Biochar and Organic Fertilizer on Soil Aggregate Stability and Contribution of Organic Carbon

Xue Zhaokun; Yu Keru; Ma Jiawei; Fang Xianzhi; He Lizhi; Liu Dan; Ye Zhengqian

doi:10.14083/j.issn.1001-4942.2025.07.014

Abstract：The study aimed to explore the solutions for solving the problems of soil structure destruction and fertility decline due to topsoil stripping,and to provide techniques for restoring such soil and barren soil improvement.Rice husk biochar was used as the main material(application rate at 0,1％and 3％),and or-ganic fertilizer(application rate at 0 and 0.8％)was used as the auxiliary material,then a soil incubation ex-periment was carried out.The stability of soil aggregates and their organic carbon contents and contributions were analyzed by the end of 180-day incubation under flooding condition to mimic paddy field.The results were as follows.(1)The application of biochar and organic fertilizer affected the particle size distribution of aggregates and promoted the formation of large aggregates.The proportion of 0.25～2-mm particle size aggre-gates increased significantly,especially in the treatment of high biochar combined with organic fertilizer.(2)The aggregate stability index mean weight diameter(MWD)increased with the increase of biochar application rate.(3)The organic carbon content of aggregates was the highest in the 0.25～2-mm ones.With the decrease of aggregate particle size,the organic carbon content of aggregates decreased.Soil organic carbon content and aggregate organic carbon content increased significantly with the increase of biochar application rate.In sum-mary,the application of biochar and organic fertilizer was beneficial to improve the stability of soil aggregates and promote the accumulation of soil organic carbon,which could be used as an effective measure to restore the quality of cultivated land with topsoil stripping and improve barren soil fertility.