Coupled Effects of Soil Texture and Hydrothermal Regimes on Soil Nutrient Spatial Patterns: Superimposed Impact of Photovoltaic Installations in Desert Ecosystems

The rapid development of photovoltaic technology is transforming China’s energy structure and reducing carbon emissions, but large-scale photovoltaic facility deployment in arid regions affects soil development and nutrient dynamics. The effects of different photovoltaic support types on soil nutrients and ecological stoichiometry, however, are not fully understood. In this study, three configurations—UFPV (under-module of fixed-axis), IFPV (inter-module of fixed-axis), and ITPV (inter-module of single-axis tracking)—and CG (control group) were compared in the Talatan Beach photovoltaic park in Qinghai. Soil carbon, nitrogen, and phosphorus stoichiometry were analyzed along with environmental drivers. Results showed soil nutrient levels were significantly lower UFPV compared to the control, while the ITPV better maintained soil nutrient levels. The relative contributions of major environmental factors to the spatial variability of soil nutrient stoichiometry were as follows: soil water content (18.49%), temperature (12.14%), belowground biomass (10.34%), clay content (9.90%), precipitation (9.86%), sand content (9.74%), silt content (9.56%), and bulk density (6.29%). Photovoltaic deployment affects soil nutrients in desert areas not only through physical shading effects, but also by reshaping the local microenvironment and creating complex cascading responses among the "photovoltaic–vegetation–soil" system, thereby indirectly influencing soil properties. These findings provide insights for ecological risk management and sustainable low-carbon development in arid regions.