A research team from the Fertilizer and Fertilization Technology Innovation Group at the Institute of Agricultural Resources and Regional Planning (IARRP), Chinese Academy of Agricultural Sciences, has revealed that coordinated management of potassium fertilizer and green manure enhances soil nitrogen retention and increases potato yield by reshaping microbial nitrogen-cycling processes. The research, titled "Sustainable potassium management with green manure reshapes microbial nitrogen cycling to enhance potato yield", was published in Agriculture, Ecosystems and Environment.

Long-term intensive potato cultivation often leads to potassium depletion and nitrogen imbalance, affecting the sustainability of agroecosystems Using metagenomic analysis and quantitative PCR, the study explained how gradient potassium fertilization and green manure application regulate key nitrogen-cycling functional genes and microbial community structures in soils. Results showed that potassium input significantly reduced the abundance of nitrification and denitrification genes (e.g., amoA/B/C, nirK/S, norB, nosZ), while increasing the expression of assimilatory and dissimilatory nitrate reduction genes (e.g., nasA/B, narG/H/I, nirB/D). This shift suppresses gaseous nitrogen losses and prolongs the availability of plant-accessible nitrogen.

The study further demonstrated that combining green manure with potassium fertilization increased soil available potassium, mineral-associated organic carbon, and organic nitrogen contents. This synergy significantly enhanced microbial diversity, optimized functional microbial community composition, and enriched beneficial microbes involved in nitrogen assimilation and potassium solubilization. Under this combined treatment, potato yields increased by 62–119% compared with no-potassium controls, alongside substantial gains in mineral-associated organic carbon and nitrogen accumulation.

Based on a decade-long field trial, the research systematically revealed the nitrogen-cycling mechanisms underlying potassium–green manure synergistic enhancement. The results provide a scientific foundation and technical pathway for improving potassium management and nitrogen-use efficiency in intensive agricultural systems, with important implications for advancing green potato production and agricultural sustainability in China.

Dr. Ning Linyi-Rui from IARRP is the first author, and Researcher He Ping and Academician Zhou Wei are the corresponding authors. The study was supported by the State Key Laboratory of Efficient Utilization of Arable Land in China, the National Natural Science Foundation of China (32272822), and the China Agriculture Research System (CARS-09-P31).

Article link：https://doi.org/10.1016/j.agee.2025.110124