This paper starts with a brief review of some leading theories in technical change and political economy. It then discusses public agricultural R&D expenditure in the United States and tries to explain why it has been decreasing in the past few decades from a political economy point of view. Economic literature on experimental stations is then reviewed, with a focus on spatial spillover of experimental station research. By using climate change as a case study, the paper highlights a dilemma between climate change adaptation and cross-region productivity equity, which calls for future research from the perspective of political economy as the global challenges facing agriculture switching from productivity to sustainability. Our bibliometric analysis shows the need for future research on the role of land grant universities and experiment stations, digital agriculture, and climate-smart agriculture as they are emerging topics within the agricultural innovation and political economy nexus.