This study developed an innovative model integrating straw subsoil deep burial (SD) and mixing plow to mitigate albic soil’s physical and chemical constraints and enhance crop yield. A field experiment with four treatments, including conventional tillage (CT), straw mulching (SM), straw subsoil deep burial (SD), and straw burning (SR), was conducted to assess impacts on soil enzyme activity, nutrient dynamics, crop yield, and soil physical properties. Results showed that SD treatment significantly improved albic soil properties compared to conventional tillage: catalase activity in the albic horizon decreased by 13.51%, reducing peroxide toxicity. In the albic horizon, alkaline hydrolysis nitrogen, total nitrogen, available phosphorus, total phosphorus, available potassium, total potassium, and organic matter increased by 29.98%, 58.70%, 36.86%, 20.46%, 5.00%, 21.70%, and 40.46%, respectively. Correspondingly, maize and soybean yield under SD reached 8686.6 kg/ha and 2245.3 kg/ha, increasing by 15.39% and 19.94% compared to CT, respectively. Additionally, SD treatment improved physical properties of the albic horizon: soil hardness reduced by 43.56%, with enhanced water-holding capacity, permeability coefficient, porosity, and hydraulic conductivity. Its findings not only boost agronomic productivity by improving crop yields but also support environmental sustainability by enhancing soil fertility, which is of great significance for ensuring food security.

In this study, a method for creating networked macropores through tillage using Eisenia fetida attracted by food sources derived from decomposing straw was proposed. The effects of Eisenia fetida activity and corn stalk addition, as well as the synergistic effects of Bacillus subtilis, on macropore formation were systematically studied. A 3D visualization technique was used to render the pore network model. When compared with undisturbed soil, the results demonstrate that cultivation using earthworms attracted by food sources from decomposing straw creates a soil pore structure with the most significant effect. The 3D porosity of the soil increased 6.90-fold, its average pore volume increased 5.49-fold, and its equivalent diameter increased 4.88-fold. Cylindrical pores, which accounted for the largest proportion (4.38%), had a channel radius of 1–5 mm and comprised approximately 86.7% of all macropores. The channel length increased by 28.5%, the average roundness decreased by 2.5%, and the average coordination number increased by 33.3%. The macroporous network structure formed by these earthworm-generated pores was more beneficial for improving the structure of phaeozem, offering technical support for the field application of earthworm farming.

This study investigated the impact of the response mechanism of tillage construction on paddy yield in black soil fields by adopting four mechanical tillage techniques, namely, rotary tillage (RT), shallow plowing (SP), deep plowing (DP), and culvert pipe drainage (CD), to solve the problems associated with the reduction in the effective tillage layer in black soil paddy fields, as well as the poor quality and low yield of paddy rice. The results showed that SP, DP, and CD techniques were able to increase the rice yield and improve the effective tillage layer of the soil and the soil structure. Among them, DP had the most obvious effect, compared with traditional RT; the fast-acting N was 37.27 mg/kg higher in the 20–30 cm soil layer, and the soil solid phase decreased by 1.86–3.90% in the soil tripartite ratio. The soil bulk density of DP in the 10–20 cm soil layer decreased by 0.08 g/cm³, and, in the 20–30 cm soil layer, it decreased by 0.03 g/cm³. These physicochemical properties promoted the development and growth of roots and increased the growth of the root system by 6.53–16.33%, with the yield also increased by up to 9.81%. The CD technique could improve paddy field drainage and increase crop yields. This study combines four mechanical tillage techniques and proposes a mechanism of tillage construction from soil structure improvement to soil physicochemical property enhancement, and then to root system and yield enhancement. This mechanism may help to guide the implementation of mechanical tillage methods in paddy fields, which will provide important insights for future agricultural practices.

This study investigated the response mechanism of tillage construction on pad-dy yield in black soil fields by adopting four mechanical tillage techniques, namely rotary tillage (RT), shallow ploughing (SP), deep ploughing (DP), and culvert pipe drainage (CD), to solve the problems associated with the reduction of effective tillage layer in black soil paddy fields, as well as the poor quality and low yield of paddy rice. The results showed that SP, DP and CD techniques were able to increase the rice yield and improve the effec-tive tillage layer of the soil and the soil structure. Among them, DP had the most obvious effect, compared with traditional RT, the fast-acting N was 37.27 mg·kg-1 higher in the 20-30 cm soil layer, and the soil solid phase decreased by 1.86%-3.90% in the soil tripartite ratio, in which these physicochemical properties promoted the development and growth of roots, increased the growth of root system by 6.53%-16.33%, with the yield increased by up to 9.81%. This study combines four mechanical tillage techniques and proposes a mechanism of tillage construction from soil structure improvement, to soil physicochem-ical property enhancement, and then to root system and yield enhancement. This mecha-nism may help to guide the implementation of mechanical tillage methods in paddy fields, which has important insights for future agricultural practices.

The degradation of soil structure in black soils has become a key factor limiting the productivity of farmland ecosystems. However, systematic studies on restoring soil physical properties and improving crop yields through biological tillage remain scarce. In this study, Eisenia fetida was employed as a biological tillage agent to create soil macropores. An orthogonal experiment with three factors was conducted to investigate the mechanisms by which different gradients of soil moisture, decomposed straw, and soil compaction affect soil pore structure and the yield of Brassica chinensis L. X-ray-computed tomography (CT) was used to quantitatively characterize the macropore network mediated by earthworms. The results indicated that the critical threshold conditions for optimized biological tillage were 50 g of decomposed straw, a compaction of 50–150 kPa, and a soil moisture content of 30–37%. Under these conditions, earthworm activity significantly enhanced the leaf dry weight of Brassica chinensis L. by approximately 55.29%, while root dry weight increased by 96.60%. Compared with treatments of low soil moisture combined with 50 g of decomposed straw, higher moisture levels further increased total biomass by 75.46%. Compared with the control, earthworm-induced macropores had 27 times more pore throats than abiotic pores, and network models showed significantly improved connectivity, indicating enhanced soil structure. This study revealed a synergistic threshold of water–food–physical resistance regulation for soil structural improvement under biological tillage and innovatively proposed a biological tillage evaluation system based on CT-quantified pore networks and root structure–function relationships. These findings provide a theoretical basis for the ecological restoration of degraded black soils.

Black soil, as a vital environment for food production, is currently facing severe degradation. Earthworm tillage is recognized as an effective approach to improving black soil structure; however, its optimal implementation strategy remains unclear. In this study, a pot experiment using Pak Choi (Brassica rapa L. ssp. chinensis) was conducted under an orthogonal design with three factors—earthworm size, application timing, and quantity. Combined with yield measurement, analysis of variance (ANOVA), and grey relational analysis (GRA), the effects of earthworm application on plant growth and soil structure were systematically evaluated. In addition, Computer Tomography (CT) scanning and three-dimensional reconstruction were employed to visualize the pore structures of representative soil samples. The results showed that large earthworms significantly enhanced both leaf and root biomass of Pak Choi, exhibiting a stronger promoting effect than small earthworms. Application at the sowing stage resulted in the greatest yield improvement, whereas applications at other growth stages had limited effects. The number of earthworms did not show a statistically significant impact under the experimental conditions, and its potential influence requires further verification under more refined density gradients. Overall, this study elucidates the mechanisms by which earthworm tillage improves soil structure and promotes crop growth, providing a theoretical basis for the restoration and sustainable utilization of degraded black soil.