Green manure is used as an environmentally friendly technology to produce clean agricultural products. This technology not only helps reduce environmental and health concerns, but can also increase productivity. Green manure is especially needed in the production of paddy. Because rice as a strategic product is the main food of people in many countries of the world. Rice production using green manure can enable countries to develop and increase healthy production. However, the acceptance of this technology is low in many rice producing countries. In this regard, this study used an integrated and extended version of the theory of planned behavior to predict and encourage the adoption of green manure technology in Iran. To collect the required data, a cross-sectional survey was performed among Iranian rice growers and the results of hypothesis testing were analyzed using partial least squares-based structural equation modeling. The results revealed that moral norms of green manure, attitude towards green manure, perceived behavioral control on using green manure, and trialability of green manure have positive and significant effects on intention towards using green manure. In addition, bootstrap analysis showed that moral norms of green manure and trialability of green manure positively and significantly mediated the (indirect) effects of subjective norms towards application of green manure on intention towards using green manure. The results led to important practical and theoretical implications that could provide new insights for policy-makers, planners, and practitioners to develop and encourage the adoption of green manure technology to produce clean and healthy agricultural products.