Nowadays, many organizations and private companies, throughout the world have been actively investigating new ICT technologies for agriculture. They are from many different industries and economic sectors, ranging from finance, engineering, food retailers, to industry associations and groups of small farming suppliers. Due to the diversity and heterogeneity of the stakeholders, one of the main problems is interoperability of IoT 'Internet of Things' nodes. Interoperability is the ability of multiple systems with different hardware and software platforms, data structures, and interfaces to exchange data with minimal loss of content and functionality. In this paper, we will present our approach to solve the interoperability by considering the current state-of-the-art through a smart farming use case. Section 2 presents the related work on interoperability lied on metadata. In section 3, we present our contribution on the implementation of metadata based on SensorML illustrated by a use case: smart irrigation system. To validate our proposal, an example of integration of temperature sensor using SensorML standard into W3C semantic web stack is designed and implemented and an assessment and discussion will be dressed in section 4. Section 5 concludes this work and we will present some perspectives.