The influence of snow cover on gross primary productivity of cultivated land in Northeast China

Abstract. Snow cover is a critical regulator of hydrological cycles and vegetation productivity in temperate ecosystems, yet its multifaceted impact on cultivated lands remains poorly quantified, especially across diverse geographical regions. This study elucidates the spatially heterogeneous by which snow cover dynamics regulate Gross Primary Productivity (GPP) on cultivated land in Northeast China, a vital grain production base. By integrating 20 years of remote sensing observations, climate records, and soil data, we employed partial correlation, ridge regression, and Partial Least Squares Structural Equation Model (PLS-SEM) to isolate the effects of snow cover parameters, including Snow Water Equivalent (SWE), Snow Cover Duration (SCD), and Snow Cover End Date (SCED). Our results reveal a distinct geographical zoning of snow cover influences: SWE dominated GPP variability in the arid Western Sand Area and Liaohe Plain, whereas SCD was the primary driver in the Songnen Plain, and SCED exerted the strongest control in the colder Changbai Mountain and Xing'an Mountain. The PLS-SEM further quantified that these impacts are mediated primarily through snow-induced modifications to spring soil moisture and temperature, with the dominant pathway shifting from hydrological benefits in water-limited plains to thermal limitations in colder high-latitude areas. These findings suggest a significant correlation between changes in snow cover and GPP of cultivated land, providing insights into the potential role of snow cover in modulating GPP dynamics.