I think that this is likely very different in different countries.
In the United Stated, farmers have long listened to radio for weather and commodity price reports. But today they also have dedicated websites for this kind of information. Plus, they may be listening to Sirius XM, podcasts, or iTunes in their air-conditioned tractor cabs.
A useful way of beginning to answer such a question, as some of the contributed responses have already suggested, should begin by listening to the farmers: engaging with them to discover what they have learnt so far and from which sources.
Also find out what sort of information did the farmers find most useful.
Out of the findings from such listening you will get insights and surprises that will help you discover not just the most appropriate media to use, but also how to present the information. Planning and designing information for delivery. Such work should always begin with listening.
In order to convey advisory messages to farmers in Adarawa state, specifically in Yola where I am presently located, radio serves as the most efficient medium, especially in rural regions where literacy levels may be low and access to alternative media is restricted.
Research consistently demonstrates the effectiveness of radio in agricultural communication, particularly in rural regions where it serves as a key source of information and entertainment. Its capacity to engage a broad audience, including those with restricted access to alternative media, renders it an essential instrument for sharing vital information. Furthermore, radio can be utilized to convey agricultural extension messages in the local language, as indicated by studies such as Dagron, A., G. (2001).
Furthermore, radio serves as a widely used platform for disseminating and educating users on agricultural matters, including innovative farming methods, production management, market data, and various other issues, alongside other ICT-related initiatives (Chauhan, 2007). The dissemination of knowledge and information via radio broadcasts is being enhanced, as it plays a crucial role in effectively reaching a large number of smallholder farmers.
Nonetheless, social media platforms such as WhatsApp, Facebook, and Instagram can be beneficial for younger farmers and individuals with internet connectivity. However, their effectiveness may be restricted to a younger, technologically adept demographic and may not perform as well in regions with poor internet access.
While ICT can be highly beneficial in equipping resource-limited farmers with up-to-date knowledge and information regarding agricultural technologies, optimal practices, market trends, pricing patterns, and weather conditions, as highlighted by UNDP (2012). The experiences of most countries indicate that knowledge management practices in agriculture have greatly advanced due to the rapid evolution of ICT, facilitating easier data and information exchange. However, in Ethiopia, the utilization of ICT for the collection and dissemination of knowledge and information remains limited.
According to Castello, & Braun, (2006), lack of collaborative learning initiatives in development communication and natural resource management, a lack of direct participation of farmers in radio programs, a mistrust of farmers in extension messages communicated through mass media, inattention of farmers to extension messages communicated through flyers, programs, brushers and documentary films, low access to radio sets to share and exchange agricultural extension messages, a top-down communication approach in which agricultural messages are diffused from woreda level to individual farmers with less farmer participation and illiterate farmers to read and understand agricultural extension messages.
In a nutshell, radio continues to be an exceptionally effective medium for delivering agricultural advisory messages, especially in regions characterized by low literacy levels and restricted access to alternative media.
Currently, social media is most effective for farmers in areas close to towns with good transport links and phone/internet access. In contrast, radio programs work better for those in remote areas with poor connectivity and no phone or internet coverage.