In today s data driven technical world, decisions are made by proper analysis of the real time data obtained from different sensors attached in the premises. The field of agriculture is also not an exception. To process these huge data, they need to be transferred to respective data processing units situated in the same premises or at remote end. In both of the cases, data transfer mechanism is performed by wirelessly interconnected specialized nodes having integrated sensors, controllers, wireless connectivity modules and portable energy sources. These nodes are popularly known as sensor nodes and the arrangement of wirelessly interconnected nodes is called Wireless Sensor Network (WSN). When WSN nodes are connected with processing units and other WSNs at remote end through internet, they constitute a networked ecosystem called Internet of Things (IoT). In this paper, we have attempted to survey the wireless protocols for IoT and their challenges while used in the field of Agriculture. Also a comparative analysis of the protocols has been provided to facilitate the researchers and farmers to choose suitable protocols for their application.