The recent advances in the Internet of Things (IoT), which has provided increasing availability of networked sensors and actuators, have given context awareness research in the UbiComp area a new perspective. In this sense, the main contribution of this paper is the proposition of a distributed architecture for IoT, called CoIoT (Context awareness in the Internet of Things). This architecture is designed to provide proactive management of the interactions with the physical environment. To evaluate the functionalities of the proposed architecture we implemented a case study in the agricultural area, specifically in the monitoring of seed analysis laboratory.