IoT and WSN, the two emerging fields, introduced efficient and reliable agricultural and livestock monitoring. Researchers are focusing these fields to introduce several new trends and techniques for agricultural automation industry. The automation industry is now seeking new opportunity in the field of agriculture and livestock. The idea of IoT is to embed a particular framework by adding computer software, sensors, and actuators and to establish the connection over internet for the purpose of uploading and processing the data over a cloud. However, IoT devices require less processing power, limtited life, heterogeneity support, platform independence, RFID, WiFi and blutooth. This support made IoT devices more suitable for the remote sensing. It is used to perform rapid and quick response on decision managment. Micro-controller technology has several application areas in agriculture where IoT devices can be implemented for the further monitoring, processing and upload semantics which improve the agriculture automation industry and crop product. In this paper, IoT in agricultural and its respective applications and challenges are discussed.