Optimized management practices decreases greenhouse emissions by improving soil aggregation structure in a wheat-maize rotation system

Objectives The effects of different irrigation and fertilization management practices on soil aggregation structure, soil pore characteristics, and greenhouse gas emissions were studied in a wheat−maize rotation system in the North China Plain, aiming to reveal the physicochemical mechanisms underlying the regulation of greenhouse gas production and emissions by water and fertilizer management.

Methods A field experiment was conducted in Quzhou County, Handan City, Hebei Province, from 2022 to 2024. Five treatments were established: conventional fertilization (CK); four-dense-one-sparse planting with shallow-buried drip fertigation (Y1); Y1 supplemented with a microbial agent (Y2); Y1 supplemented with bio-organic fertilizer (Y3); and Y1 supplemented with a soil conditioner (Y4). Greenhouse gas (N₂O, CO₂, and CH₄) fluxes, topsoil aggregate composition, and soil pore structure were monitored.

Results Compared with CK, the Y1 treatment reduced greenhouse gas emission intensity (GHGI) by 21.21%, increased the mean weight diameter (MWD) of aggregates by 17.59%, and improved soil porosity by 29.38%. The application of functional fertilizers (Y2, Y3, and Y4) further improved soil structure and reduced GHGI. Compared with Y1, the mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates under Y2, Y3, and Y4 treatments increased by 25.82% and 29.07% on average, while soil porosity increased by 10.46% and GHGI decreased by 21.15%. No significant differences were observed among Y2, Y3, and Y4. Correlation analysis showed that soil porosity, fractal dimension, and pore density were significantly and positively correlated with the proportion of >2 mm and 1−2 mm aggregates. Enhancing the proportion of large aggregates mitigated greenhouse gas emissions from croplands by improving soil pore structure and aeration, thereby reducing the GHGI in the wheat-maize rotation system of the North China Plain.

Conclusion In the wheat−maize rotation system of the North China Plain, the management strategy of combining four-dense-one-sparse planting with shallow-buried drip fertigation can simultaneously achieve water saving, fertilizer saving, and yield increase. Based on this, the application of functional fertilizers, especially bio-organic fertilizer, can further significantly enhance soil aggregate stability, improve soil aeration, and reduce greenhouse gas emissions. Therefore, this combination of management techniques represents an optimized cultivation and fertilization model for the North China region.