Objectives  The effects of different farming and fertilization methods on soil physical and chemical properties and wheat yield were compared, in order to solve the problems of shallow ploughing layer and low nutrient capacity in lime concretion black soil, and improve the quality and yield of wheat.

  Methods  The field experiment was established in 2019-2020 using a split-plot design with rotary tillage and deep tillage as the main plots. Five fertilizer managements, including no organic fertilizer and biochar applied treatment (CK), application of 15 t hm⁻² organic fertilizer (15M), application of 22.5 t hm⁻² organic fertilizer (22.5M), application of 15 t hm⁻² biochar (15B) and application of 22.5 t hm⁻² biochar (22.5B). The effect of wheat yield and soil physicochemical properties at different soil layers were determined. Then the changes in soil physicochemical indices and wheat yield were studied for soil layers with different treatments.

  Results  Deep tillage, biochar and organic fertilizer all significantly increased soil pH value in 0-10 cm, deep tillage significantly increased water content in 10-30 cm, and decreased bulk density and compactness of 10-30 cm. Biochar improved soil bulk density and compaction better than organic fertilizers. Deep plowing combined with biochar or organic fertilizer significantly increased the content of organic matter and total nitrogen in the 10-30 cm soil layer, and high amount of organic fertilizer had the best effect on improving available nutrients. Rotary tillage and increased application of organic fertilizer significantly increased the diseased ear rate of wheat scab. Deep ploughing significantly decreased the disease index of scab, and the deep ploughing 22.5M treatment decreased the disease index by 52.6% compared with the rotary plowing 22.5M treatment. The yield for two consecutive years showed that deep ploughing significantly increased wheat yield, and high-amount biochar and organic fertilizer treatments significantly increased yield by 18.3% and 9.0% compared with deep ploughing CK treatment. Structural equation model analysis showed that deep tillage and biochar promoted wheat yield mainly by affecting soil physical properties, and organic fertilizer significantly improved soil chemical properties, but high amounts of organic fertilizer could promote the occurrence of scab.

  Conclusions  Deep tillage combined with high amount of biochar or appropriate amount of organic fertilizer can effectively improve the barrier factors of lime concretion black soil and increase wheat yield.