The agricultural sector stands as a pivotal juncture in economic development, with the integration of modern technologies like the Internet of Things (IoT) and blockchain significantly streamlining and enhancing farming practices. The prevalence of IoT in agriculture has grown substantially, with its applications seamlessly incorporating activities tracking and updating. Utilizing sensors facilitates farmers in efficiently gathering essential information and monitoring soil and crop conditions. However, the increasing sophistication of IoT attacks raises security concerns, making blockchain technology crucial in addressing these challenges. Blockchain not only plays a pivotal role in ensuring security and privacy but also extends the range of IoT applications in agriculture. This article provides a comprehensive review of current research on both blockchain and IoT technologies in the context of smart agricultural systems, while also outlining potential future research directions in this field.