Abstract:In order to investigate the effects of biochar application on soil aggregates stability, organic carbon, and total nitrogen distribution, further elucidate the long-term effective mechanism of biochar addition on farmland in the hilly area of western Henan Province, China, a 5-years field experiment was conducted to explore the effects of biochar application(0 (C0), 20 (C20), 40 (C40) t/hm2) on soil aggregates composition and stability, and illustrated the distribution characteristics of organic carbon and total nitrogen in soil aggregates. The results showed that biochar application with 20 and 40 t/hm2 increased the contents of > 0.5 mm mechanical and > 0.053 mm water stable aggregates. In the 0-20 cm soil layer, compared with the control, C20 and C40 treatments increased the >0.25 mm mechanical aggregate (DR0.25) by 3.78% and 6.83%, increased >0.25 mm aggregate water stability (WR0.25) by 31.0% and 49.45%, decreased unstable soil aggregate index (ELT) by 4.30% and 6.85%, decreased proportion of soil aggregate destruction (PAD) by 9.71% and 14.77%, increased the mean weight diameter (MWD) of soil aggregates by 28.44% and 45.34%, and increased the geometric mean diameter (GMD) significantly by 32.04% and 54.92%. The content of organic carbon and total nitrogen increased with the increase of biochar application rates in each size fraction, was the highest in 0.25~0.053 mm aggregate. The contents of organic carbon and total nitrogen in 0-20 cm soil layer was higher than that in the 20-40 cm soil layer. With the increase of biochar application amounts, the contribution rates of organic carbon and total nitrogen increased at >2, 2~0.25 and 0.25~0.053 mm aggregates, and the contribution rates of organic carbon and total nitrogen decreased at <0.053 mm aggregate. In general, biochar improved the soil aggregate structure, increased the content and stability of soil macro-aggregate, and increased the contents of organic carbon and total nitrogen in each size fraction, which was beneficial to maintain the soil fertility and the long-term healthy development of farmland in the hilly area of western Henan Province.