Evaluation of Technical Readiness of the Whole-Process Optimized Fertilization Plan for Vitis vinifera ‘Red Globe’ at a County Scale

Excessive fertilization in grape production reduces profitability and harms the environment. A five-year field experiment and household survey in Xiangyun County, Yunnan, evaluated a whole-process optimized fertilization plan for Vitis vinifera ‘Red Globe’ (hereafter abbreviated as Red Globe Grapes) and its spatial diffusion. The optimized plan reduced N, P2O5, and K2O inputs by 385.28, 298.65, and 154.02 kg ha−1, increased yield by 18.4%, and raised net income by 41,574 RMB ha−1. After five years, partial factor productivity of nitrogen (PFPN, an indicator of nutrient management performance used here to assess adoption at the farmer level)—a proxy for technical readiness—was highest in the core demonstration area and declined with distance. Spatial Durbin modeling showed that spillover effects attenuated beyond roughly 30 km, with an optimal promotion radius near 10 km and an effective promotion radius of 17.5 km. Farmer education generated positive indirect spillovers. Promotion intensity had a negative local effect but net positive spatial feedback. In the development area, adoption remained unstable without sustained support. Scaling optimized fertilization therefore requires differentiated extension strategies that leverage social learning among neighboring farmers.