Effects of Biochar Application on Aggregate Stability and Organic Carbon Content in Fluvo-Aquic Soil

Liu Zijian; Li Han; Ma Xinyu; Sun Shuchen

doi:10.14083/j.issn.1001-4942.2026.03.013

Abstract：A four-year experiment was conducted in a winter wheat-summer maize rotation farmland in the western Shandong Plain.Biochar was applied annually during the winter wheat season with five treatments as 0(CK),1.14 t/hm2(T1),2.28 t/hm2(T2),3.42 t/hm2(T3)and 4.56 t/hm2(T4).After four years,the effects of biochar on soil aggregate stability and organic carbon content in the topsoil were evaluated.The results showed that the aggregates＜0.25 mm and their organic carbon content dominated in the topsoil.Bio-char application enhanced the proportion and organic carbon of aggregates＞0.25 mm in both 0～10-cm and 10～20-cm soil layers,which increased first and then decreased with the increase of biochar application rate.The mean weight diameter(MWD)and geometric mean diameter(GMD)of soil aggrevates,and the propor-tion of＞0.25 mm macroaggregates(R0.25)also increased first and then decreased with the increase of biochar application rate.T3 treatment had the best effect on improving soil aggregate stability.The soil organic carbon(SOC)content increased by 31.81％to 79.81％and 26.10％to 70.74％in the 0～10-cm and 10～20-cm soil layers,respectively,and T3 and T4 resulted in significantly higher SOC content compared to T1 and T2.Sig-nificant positive correlations were found between MWD,GMD and R0.25 in 0～10-cm and 10～20-cm soil lay-ers,while the percentage of aggregate destruction(PAD)showed significantly negative correlations with MWD,GMD and R0.25.In conclusion,continuous application of biochar for four years significantly improved soil aggregate stability and SOC content,and basal application 3.42 t/hm2 biochar during the winter wheat sea-son had a better effect.