Application of the diffusion of innovation theory to identify factors affecting the use of treated wastewater in crop irrigation: a study in Tehran province

The sustainability of water resources and their optimal utilization have emerged as critical global challenges. In Iran, water scarcity combined with population growth has intensified pressure on existing water supplies. Given the agricultural sector's substantial share in freshwater consumption, effective water resource management in this domain is particularly vital. One promising solution is the use of treated wastewater (TWW), which offers considerable economic, environmental, and social benefits. However, its adoption by farmers faces notable barriers. This study aims to investigate the factors influencing Iranian farmers' willingness to use TWW for irrigating agricultural crops. The research employs the Diffusion of Innovation (DOI) theoretical framework to analyze farmers' adoption behavior. Additionally, the study controls for individual-level variables within the model—an approach that has received limited attention in previous structural and model-based research. The statistical population comprises farmers in Tehran Province, located in central Iran. Data were collected via a structured questionnaire and analyzed using structural equation modeling (SEM). The results demonstrate the effectiveness of the DOI framework, with all hypothesized relationships proving statistically significant. The model explains 60.1 % of the variance in farmers' acceptance of TWW for irrigation purposes. Key DOI constructs—relative advantage, compatibility, complexity, observability, and trialability—were found to significantly influence adoption. Despite its contributions, the study is limited by its geographic focus, the absence of broader cultural, institutional, and economic considerations, and constraints on the generalizability of its findings. Nevertheless, the results provide a valuable foundation for designing extension programs, educational initiatives, and policy support mechanisms aimed at promoting sustainable agriculture through the use of alternative water resources.