Abstract : Agricultural technology extension is an important part of the transformation of scientific and technological achievements into productivity. Revealing the spatial spillover effects of township agricultural technology extension is of great help for improving agricultural technology extension strategies from the county level or higher level to promote high-quality development and modernization of agriculture. Therefore, taking citrus mulching technology as examples, the panel data of 60 townships in Lipu, Yangshuo, Yongfu, Lingchuan and Quanzhou in Guilin city was used to analyze the rule of the diffusion of the two agricultural technology extension methods, demonstration and training, at the township level. Firstly, the statistical analysis and ArcGIS technology was used to analyze the spatio-temporal rule of the diffusion of citrus plastic mulching technology. Secondly, spatial spillover effects of the two agricultural technology extension methods were tested by using spatial econometric models. Our findings showed that: (1) Township agricultural threefold extension imposed spatial spillover effects. That was, the extension services in one town could facilitate the technology diffusion in other towns. The closer the spatial distance was, the more farmers communicated with each other, so the spatial spillover effect between neighboring towns was stronger. (2) For easy technologies, demonstrations had strong spatial spillover effects whereas training had no significant effect. Demonstrations not only had the direct impact, but also had a greater spillover effect. (3) The diffusion of the use of plastic film in the studied area followed a strong spatial and temporal pattern. In the spatial dimension, plastic mulching technology formed a diffusion pattern with Xiuren Town and Baisha Town as the source of diffusion, with asymptotic diffusion as the mainstay and jump diffusion as the supplement. In terms of time, the diffusion of citrus plastic mulching technology experienced a rapid growth stage and entered a stable development stage temporally. According to these findings, we propose policy suggestions for improving the efficiency of agricultural technology extension by utilizing the spatial spillover effects: Firstly, differentiated allocation of agricultural technology promotion resources should be adopted. In formulating agrotechnology promotion strategies, full consideration should be given to such factors as the attributes of agricultural technology, the agricultural characteristics of each township and the level of farmers' literacy, so as to formulate targeted promotion strategies. Secondly, guiding social forces to create agricultural science and technology demonstration parks. On the one hand, the number of parks should be increased and their locations optimized in order to give full play to the direct and indirect effects; on the other hand, social forces should be actively guided to jointly set up demonstration parks of high scientific and technological standards. Thirdly, utilizing the role of social networks in the dissemination of information to farmers. The application of Internet technology in social networks in agrotechnology promotion should be expanded, and farmers should be encouraged to actively participate in agrotechnology exchanges and give full play to their subjective initiative. 

Keywords: township-level agricultural technoloy extension; spatial spillover effects; spatial econometric models; spatial and temporary patterns; satell-ite remote sensing data