To investigate the effects of biochar application on winter wheat yield and soil carbon and nitrogen under rotary tillage and deep loosening conditions, and to explore the optimal combination of tillage and biochar application rates for winter wheat. Through field trials, two types of tillage methods, rotary tillage (XG) and deep loosening (SS), and three biochar application rates, 0, 4.5 (B1), and 9 t/hm2 (B2), differences in winter wheat yield and soil carbon and nitrogen between treatments were comparatively analyzed. Tillage practices and biochar application rates had significant effects on microbial biomass carbon and nitrogen, soil total carbon, soil nitrate nitrogen residues and total nitrogen , and the effect of the interaction between the two on total nitrogen and microbial carbon reached significance in 2022 and 2023, respectively. Compared with the rotary tillage treatment, in the 0-20 cm soil layer, total carbon increased by 13.9% and total nitrogen content increased by 29.5% in the deep loosening treatment, the deep loosening treatment significantly promoted the increase of soil microbial biomass carbon and nitrogen content in the 20-30 cm soil layer, while nitrate nitrogen residue was significantly reduced by 8.5%. Compared with no biochar application, biochar application increased soil microbial biomass carbon and nitrogen content in the 0-30 cm soil layer, and reduced soil nitrate nitrogen residue in the 0-50 cm soil layer, resulting in an increase of total carbon and total nitrogen by 22.4 % and 6.7 %, respectively. In 2022 and 2023, winter wheat yields were significantly increased by 15.8% and 12.0% in deep loosening and biochar application treatments, respectively, compared with the conventional XG treatment, with the highest in the SSB2 treatment at 9.8 t/hm2 and 9 t/hm2, respectively. Comprehensive analysis showed that deep loosening + 9 t/hm2 biochar had the best effect, it is a combination of tillage and charcoal application that can be applied and promoted for high yield and improved soil fertility. |