Integrating Agrivoltaics with Water–Fertilizer Management Enhances Wheat Growth and Yield in a Semi-Arid Sandy Region

Agrivoltaics provides a potential pathway to integrate crop cultivation with solar power generation in arid and semi-arid regions, but wheat responses to the heterogeneous microenvironment within photovoltaic arrays remain unclear. A field experiment was performed in the semi-arid region during 2024 and 2025 to evaluate the effects of agrivoltaic systems equipped with integrated water–fertilizer management on wheat growth and yield. Conventional open-field cultivation without photovoltaic panels or water–fertilizer management was used as the control (Open). Within the photovoltaic arrays, two planting positions were compared: the unshaded area between panel arrays (Gap) and the shaded area beneath panels (Under). Averaged across two years, grain yield was 88.6% and 40.9% greater in the Gap and Under treatments, respectively, than in the Open treatment. The Gap treatment showed the greatest root development, with root length and surface area increasing by 27.0% and 17.9% on average, respectively. The microenvironment within photovoltaic panels and water–fertilizer supply promoted yield formation of wheat in the Gap treatment, contributing to increases in spike number, grains per spike, and 1000-grain weight by 17.6%, 53.1%, and 39.0%, respectively. Despite shading in the Under treatment, water–fertilizer coupling in agrivoltaics improved soil moisture, organic carbon, and available nutrients, supporting biomass accumulation and yield formation. Despite additional water–fertilizer supply costs, the agrivoltaic system increased net revenue by 3017 CNY ha−1 compared with the conventional system. Moreover, in the drier year, the smaller yield reduction under agrivoltaic systems indicated a climate-buffering potential. These findings suggest that integrating agrivoltaics with water–fertilizer management could enhance wheat productivity in semi-arid sandy regions.