Review of nitrogen cycling in temperate winter soil under climate change.

In recent years, the biogeochemical cycling of nitrogen (N) in soils under temperate climates during winter has received growing attention due to rising N emissions and the accumulation of N on the soil surface and in nearby water bodies. While the N cycle has traditionally been considered to slow during cold periods, recent studies show that freeze-thaw cycles (FTCs) can significantly reshape N dynamics by altering soil structure and stimulating microbial activity. This review synthesizes key abiotic drivers, such as soil moisture, temperature, and snow cover, along with anthropogenic influences that affect N transformations and transport in winter. We identified the key research gaps in the existing approaches and emphasized the need to incorporate winter N fluxes into annual N budgets to improve our understanding of terrestrial N cycling under climate change.