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.

Human agricultural activities can impact the soil microbial ecosystem, but the future implications of such changes remain largely unknown. This study aimed to explore how soil microbes survive and reproduce under the pressure of human agricultural cultivation and whether they resist or adapt. A 10-year continuous experiment was conducted, planting a maize and soybean rotation (control group), alfalfa (legume), and wheat (poaceae) to study the impact of different crop planting on soil microbial communities. During the experiment, the physical and chemical properties of the soil samples were measured, and the rhizosphere microbial communities were analyzed. Different crop plantings had varying effects on soil microbial species diversity, but these differences were relatively limited. The relative abundance of Cyanobacteriales (order) was higher in wheat than in alfalfa. Moreover, Cyanobacteriales were positively correlated with soil peroxidase, thereby promoting wheat growth. In addition, nutrition for fungi is mainly derived from decaying straw and plant roots. This study divided soil microbes under agricultural cultivation conditions into three categories: adaptive microbes, neutral microbes, and resistant microbes. At the ecological level of plant rhizosphere microbes, the plant rhizosphere soil microbial community showed a coevolutionary relationship with human cultivation activities. Future research needs to pay more attention to the adaptability of soil microbial communities to agricultural cultivation and the potential impact of this adaptability on the global ecosystem.

Low productivity in albic soils often results in excessive nitrogen input, while straw return further increases nitrogen accumulation through decomposition. To address this issue, a three-year field experiment was conducted in albic soils of high, medium, and low fertility. Two nitrogen management strategies were assessed: nitrogen addition and reduction. Addition treatments included conventional nitrogen application rate alone (N), straw return (8250 kg ha⁻¹) with conventional nitrogen application rate (SN), and straw return with increased nitrogen (SN₊). Reduction treatments comprised SN and straw return with 10%, 20%, and 30% reduced nitrogen (SN_0.9, SN_0.8, and SN_0.7). Soil physical properties, nutrient content, and rice yield were evaluated. Results showed that SN_0.9 exhibited advantages in high-fertility albic soils, as it increased rice yield and improved some soil quality while reducing the nitrogen input by 10%. However, yield under SN_0.9 declined progressively over the three years, indicating limitations of long-term application. SN performed better than both N and SN₊ in medium- and low-fertility albic soils, offering better yield and soil quality improvements. However, nitrogen overaccumulation risk under continuous application should not be overlooked. These findings highlight that fertility-based nitrogen adjustment combined with straw return can simultaneously improve rice productivity and soil quality while reducing nitrogen input in albic soils.

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.

Soybean ( Glycine max (L.) Merr.) is an important food crop in Northeast China. However, intensive cultivation relying on long-term high nitrogen fertilizer input has led to the loss of soil organic carbon and the decline of cultivated land quality in the black soil region, compromising soil sustainability. Therefore, it is urgent to explore a cultivation mode that achieves both stable soybean yield and coordinated improvement of soil sustainability. The application of biochar and straw return presents a promising strategy to enhance crop productivity and agricultural sustainability. However, the mechanisms underlying these improvements, particularly those driven by the combined application of straw and biochar under reduced nitrogen application, remain unclear. From 2022 to 2023, a field experiment was conducted on black-calcium soil using ‘Dongnong 55’ soybeans. Two biomass-return methods were evaluated: straw addition and a straw-biochar mixture addition, under six treatments: CK (conventional N with full straw return), SN2 (80% N with full straw), SN3 (60% N with full straw), SBN1 (conventional N with straw - biochar mix), SBN2 (80% N with straw - biochar mix), and SBN3 (60% N with straw - biochar mix). The results revealed that straw–biochar co-application improved the soil hydrothermal environment and nutrient supply compared with straw return alone. In the 0–20 cm soil layer, soil moisture content increased by 9.0% - 14.3%, while available N, P, and K increased by 47.5%–48.9%, 56.8%–71.7%, and 28.4%–41.2%, respectively. These improvements enhanced soybean physiological performance, increasing chlorophyll content, net photosynthetic rate, and leaf intrinsic water use efficiency by 12.3%, 20.6%, and 16.9%, respectively. Notably, SBN2 increased soybean yield by 9.3%–11.0% compared with SN2, and maintained a yield statistically comparable to SBN1 despite a 20% reduction in N input. Therefore, SBN2 was identified as the optimal treatment because it maintained soybean yield while reducing N fertilizer input and improving soil water, heat, nutrient supply, and resource-use efficiency. This study provides a valuable reference for managing agricultural straw, biochar utilization, and nitrogen fertilizer.

Maximizing the agricultural output on inherently infertile land and minimizing the environmental cost remain central research imperatives. Albic black soil typifies such infertility. Conventional practice relies on fertilization and straw incorporation, but the albic layer’s impermeability funnels applied nutrients into adjacent aquatic systems. Therefore, this study developed deep placement fertilization by lodging fertilizer directly within the albic layer to block hydrologic loss. The feasibility of mechanization was first validated in pot experiments. Soybeans were allocated to six treatments simulating fertilizer placement at different soil depths: control (C), control and fertilizer (CF), surface soil mixing (SM), surface soil mixing and fertilizer (SMF), plow pan soil mixing (PM), and plow pan soil mixing and fertilizer (PMF). The treatments used 20 cm tillage, and the data were collected after 15, 25, and 35 days and at harvest. Integrative transcriptomic, proteomic, metabolomic, and soil microbiome profiling revealed that fertilizer positioned at 25 cm in the albic layer increased yield, restructured the rhizobiont community and promoted arbuscular mycorrhizal fungal colonization. Among the fertilizer treatments, CF had the best growth, and SMF was inhibited by a nutrient shortage. SMF and PMF lost water faster than CF. Abscisic acid (ABA) conveyed the subterranean fertilization signal to the leaf. The enrichment of Vicinamibacterales, Xanthobacteraceae, and Glomeromycota in soil lowered the ABA content in the roots, which upregulated thymidine kinase and peroxidase upon arrival in the leaf, increasing yield. These findings provide a transferable benchmark for any parent material exhibiting poor hydraulic conductivity.